identification of novel biomarkers for predicting
TRANSCRIPT
Research ArticleIdentification of Novel Biomarkers for Predicting Prognosis andImmunotherapy Response in Head and Neck Squamous CellCarcinoma Based on ceRNA Network and ImmuneInfiltration Analysis
Ya Guo ,1 Wei Kang Pan ,2 Zhong Wei Wang ,1 Wang Hui Su ,1 Kun Xu ,1
Hui Jia ,1 and Jing Chen 1
1Department of Radiation Oncology, The Second Affiliated Hospital, Xi’an Jiao Tong University, Xi’an, 710004 Shaanxi, China2Department of Pediatric Surgery, The Second Affiliated Hospital, Xi’an Jiao Tong University, Xi’an, 710004 Shaanxi, China
Correspondence should be addressed to Ya Guo; [email protected]
Received 3 September 2021; Revised 23 October 2021; Accepted 19 November 2021; Published 6 December 2021
Academic Editor: Rui Liu
Copyright © 2021 Ya Guo et al. This is an open access article distributed under the Creative Commons Attribution License, whichpermits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Objectives. Patients with head and neck squamous cell carcinoma (HNSCC) have poor prognosis and show poor responses toimmune checkpoint (IC) inhibitor (ICI) therapy. Competing endogenous RNA (ceRNA) networks, tumor-infiltrating immunecells (TIICs), and ICIs may influence tumor prognosis and response rates to ICI therapy. This study is aimed at identifyingprognostic and IC-related biomarkers and key TIIC signatures to improve prognosis and ICI therapy response in HNSCCpatients. Methods and Results. Ninety-five long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and 1746 mRNAs wereidentified using three independent methods. We constructed a ceRNA network and estimated the proportions of 22 immunecell subtypes. Ten ceRNAs were related to prognosis according to Kaplan–Meier analysis. Two risk signatures based,respectively, on nine ceRNAs (ANLN, CFL2, ITGA5, KDELC1, KIF23, NFIA, PTX3, RELT, and TMC7) and three immune celltypes (naïve B cells, neutrophils, and regulatory T cells) via univariate Cox regression, least absolute shrinkage and selectionoperator, and multivariate Cox regression analyses could accurately and independently predict the prognosis of HNSCCpatients. Key mRNAs in the ceRNA network were significantly correlated with naïve B cells and regulatory T cells and withstage, grade, and immune and molecular subtype. Eight IC genes exhibited higher expression in tumor tissues and werecorrelated with eight key mRNAs in the ceRNA network in HNSCC patients with different HPV statuses according tocoexpression and TIMER 2.0 analyses. Most drugs were effective in association with expression of these key signatures (ANLN,CFL2, ITGA5, KIF23, NFIA, PTX3, RELT, and TMC7) based on GSCALite analysis. The prognostic value of key biomarkersand associations between key ceRNAs and IC genes were validated using online databases. Eight key ceRNAs were confirmedto predict response to ICI in other cancers based on TIDE analysis. Conclusions. We constructed two risk signatures toaccurately predict prognosis in HNSCC. Key IC-related signatures may be associated with response to ICI therapy.Combinations of ICIs with inhibitors of eight key mRNAs may improve survival outcomes of HNSCC patients.
1. Introduction
Head and neck cancer (HNC) is among the most commonmalignancies worldwide, accounting for about 600,000 newcases annually and 330,000 deaths [1]. Head and neck squa-mous cell carcinoma (HNSCC) is the predominant patho-logical subtype, comprising more than 90% of HNC cases[2]. Despite advances in surgery and radiotherapy, the 5-
year overall survival (OS) rate for HNSCC is still unsatisfac-tory [3, 4]. Thus, there is an indisputably urgent need toidentify effective biomarkers to predict prognosis and OSof patients with HNSCC.
Regulatory competing endogenous RNA (ceRNA) net-works, consisting of long noncoding RNAs (lncRNAs),microRNAs (miRNAs), and mRNAs, have a crucial role inthe processes of tumor occurrence and progression and in
HindawiBioMed Research InternationalVolume 2021, Article ID 4532438, 42 pageshttps://doi.org/10.1155/2021/4532438
prediction of prognosis [5, 6]. Furthermore, accumulatingevidence suggests that immune cell infiltration may have asignificant impact on the prognosis of HNSCC patients [7,8]. Although the prognostic value of ceRNA networks andimmune cell infiltration in HNSCC have been reported,few studies have combined ceRNA networks and immunecell infiltration to predict prognosis in HNSCC patients;moreover, these studies have limitations, and their conclu-sions have been inconsistent. Further, few studies have hadtheir results successfully confirmed in another independentdatabase, and in many, a single analytical method was usedto explore key molecules or immune cells [5, 9–11]. More-over, in HNSCC, multiple clinical characteristics, includinghuman papillomavirus (HPV) status, immune subtype,molecular subtype, grade, and stage, are associated withprognosis [12, 13]. There has not been sufficient systematicevaluation of the association among ceRNA-network RNAs,immune cell infiltration, and these clinical characteristics tofully elucidate the roles of these factors in prognosis. There-fore, a systematic scientific approach is needed to identifyeffective biomarkers for risk assessment of patient prognosis.
HNSCCs comprise a group of highly heterogeneous andimmunosuppressive cancers.
Immunotherapy is aimed at increasing the activity of theimmune system to eliminate cancer cells [14]. Immunecheckpoint (IC) inhibitors (ICIs) represent a broadly effec-tive immunotherapy that can block inhibitory IC pathwaysto restore antitumor immunity.
Anti-PD1/PDL1 ICIs can improve antitumor immuneactivity [4]. Although ICIs exert beneficial therapeutic effectson HNSCC, the response rate to them is still low [15].Therefore, identifying biomarkers able to predict ICI treat-ment response can contribute to patient screening and indi-vidualized treatment approaches and is of great significancefor standardizing immunosuppressive therapy and improv-ing the prognosis of HNSCC patients. Previous studies haverevealed that the expression of immunosuppressive mole-cules and tumor-infiltrating immune cells (TIICs) may reg-ulate the response rate to immunotherapy and prognosis inHNSCC patients. A previous study proposed the epithe-lial–mesenchymal transition CYT Index as a superior pre-dictor of prognosis and immunotherapy response acrossHNSCC [16], and immune cell infiltration scores were iden-tified as sensitive prognostic biomarkers and predictive indi-cators for immunotherapy response [8]. However, noreliable biomarker for predicting response to ICIs and prog-nosis in HNSCC has yet been identified [17, 18].
In this study, mRNA, lncRNA, and miRNA expressionprofiles of HNSCC were downloaded from The CancerGenome Atlas (TCGA) database to construct a ceRNA net-work. CIBERSORT (cell type identification by estimatingrelative subset of known RNA transcripts) was used to esti-mate the abundance of 22 immune cells based on TCGAdataset. Furthermore, two prognostic signatures were devel-oped using a comprehensive bioinformatics method. Next,the association between key genes and immune cells wasevaluated via coexpression analysis. We systematically inves-tigated the associations between key ceRNA signatures andclinical characteristic (including stage, grade, and immune
and molecular subtype). Moreover, IC correlation analysisand key ceRNA-related drug targets were performed toassess the predictive ability of these biomarkers with respectto ICI treatment response in HNSCC and to explore poten-tial targets for improving the effectiveness of immunother-apy. Finally, the prognostic value of key biomarkers andthe associations between key ceRNAs and IC genes were val-idated using online databases.
2. Materials and Methods
2.1. Data Analysis and ceRNA Network Construction. RNAsequencing (RNA-seq) and miRNA-seq data and clinicalinformation for HNSCC patients were extracted from TCGAdatabase (https://gdc-portal.nci.nih.gov/) [19]. HTseq-countprofiles were obtained. In addition, practical extraction andreports Language (Perl) scripts were used to merge all clinicaldata. The R software (version 3.6.3, https://www.r-project.org/) was used to process downloaded files, to convert andeliminate unqualified data, to apply a relatively conservativeapproach to the data analysis, and to identify a suitablenumber of differentially expressed mRNAs (DEmRNAs),miRNAs (DEmiRNAs), and lncRNAs (DElncRNAs). Thelimma, edgeR, and DESeq2 R packages were used for differ-ential expression analysis. Log fold change > 1 or <−1 andfalse discovery rate- (FDR-) adjusted P value < 0.05 wereused as the thresholds to identify significantly expressedbiomarkers. Only biomarkers that were identified usingthree independent analysis methods were selected as thefinal DEmRNAs, DEmiRNAs, and DElncRNAs [20]. AceRNA network was established using the “GDCRNATools”R package. The ceRNA network was evaluated by hypergeo-metric testing and correlation analysis. P < 0:05 was consid-ered to indicate a statistically significant result [21]. Finally,Cytoscape v.3.7.2 was used to visualize the ceRNA net-work [22].
2.2. Construction and Confirmation of ceRNA-RelatedPrognostic Model. We performed univariate Cox regression,least absolute shrinkage and selection operator (LASSO),and multivariate Cox regression analyses to identifyprognosis-related signatures. Moreover, we plotted receiveroperating characteristic (ROC) curves for 1-year, 3-year,and 5-year survival and calculated the corresponding areaunder the curve (AUC) values using the survival and timeROC packages to assess the predictive ability of the ceRNA-related signatures [23]. An AUC of <0.5 was consideredinsignificant. Patients were then divided into high- andlow-risk groups according to the average risk score. We fur-ther calculated survival differences between the high- andlow-risk groups [24]. Next, we performed univariate andmultivariate Cox regression analyses to determine whetherthe risk score based on key ceRNAs was independent of otherclinical characteristics (age, sex, grade, and stage) in the pre-diction of HNSCC prognosis. A hazard ratio ðHRÞ > 1 andP < 0:05 were considered to indicate unfavorable prognosticfactors, whereas HR < 1 and P < 0:05 indicated favorableprognostic factors [25].
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2.3. Construction of Immune Cell-Related Prognostic Model.The CIBERSORT algorithm was used to estimate the abun-dance of 22 immune cell subtypes according to the RNA-seq count data [26]. The associations between immune celltypes and prognosis were investigated by univariate Coxregression, LASSO regression, and multivariate Cox regres-sion. We further assessed the sensitivity and specificity ofimmune cell-related prognostic models using ROC curves.In addition, we performed an independent prognostic anal-ysis to assess whether the risk score based on key immunecells could predict HNSCC prognosis independently ofother clinical characteristics.
2.4. Associations between Key ceRNAs and SignificantImmune Cell Subtypes. The associations between significantmRNAs in the ceRNA network and key immune cells wereinvestigated using Pearson correlation coefficients. More-over, we analyzed the associations between the gene riskscore and key immune cells.
2.5. Clinical Correlation Analysis. The Tumor Immune Sys-tem Interactions Database (TISIDB; http://cis.hku.hk/TISIDB) was used to explore Spearman correlationsbetween the identified key ceRNAs and clinical character-istics. Moreover, the expression distribution patterns ofnine key ceRNAs across immune and molecular subtypeswere determined using TISIDB [27]. The immune sub-types comprised five groups: C1 (wound healing), C2(IFN-gamma dominant), C3 (inflammatory), C4 (lympho-cyte depleted), and C6 (TGF-β dominant) [12]. HNSCCcan be classified into four molecular subtypes, namely,atypical (AT), basal (BA), classical (CL), and mesenchymal(MS) [13].
2.6. Correlations between Immunotherapy Response and KeyceRNAs. The expression of ICs is correlated with theimmune response to immunotherapy. We extracted theexpression levels of eight immune-checkpoint genes(CD274, CTLA4, HAVCR2, LAG3, PDCD1, PDCD1LG2,
SYNM
SYBU
ACSL1
SASH1
PRKAA2
DIO2
CFL2
RASD1
hsa-miR-130b-3p
LPL
hsa-miR-454-3p
PRUNE2
NFIX
SCARA3
TACC2
NFIA
GPT2
GADD45B
H19
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PDGFRB
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EN2 CHEK1
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RFLNBCOL5A2
PI15ITGA11
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PDK4
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EMP1PTX3
ADAMTS7
HELLShsa-miR-29c-3p
COL7A1 hsa-miR-7-5p
TFRC
ITGA5
KIRREL1
hsa-miR-338-3p
SPARC
VAV2
KCNQ1OT1
hsa-miR-335-5p
TMC7
ANLN
HAS2
CDC25B
APLNHOXC11
SCN8A
(g)
Figure 1: Identification of DElncRNAs, DEmiRNAs, DEmRNAs, and construction of the ceRNA network. Differentially expressed geneswere identified by three independent methods. (a) Deseq2, (b) edgeR, and (c) limma. (d–f) Venn diagram displaying the intersection of(d) DElncRNAs, (e) DEmiRNAs, and (f) DEmRNAs. (g) Construction of the ceRNA network. Red circles represent miRNAs, greencircles represent lncRNAs, and purple circles represent mRNAs. TEC: to be experimentally confirmed; IG: immunoglobulin. Log foldchange > 1 or <−1 and FDR-adjusted P value < 0.05 were used to identify significantly expressed biomarkers.
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Figure 2: Survival analysis of key members in the ceRNA network. (a–j) K-M survival curves for the significant members of the ceRNAnetwork. (a) ACSL1, (b) CDCA4, (c) GNA12, (d) hsa-miR-29c-3p, (e) hsa-miR-130b-3p, (f) ITGA5, (g) KDELC1, (h) PRKAA2, (i)PRUNE2, and (j) PTX3.
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TIGIT, and SIGLEC15) and compared their differences inexpression between tumor and normal tissues in HNSCCusing the R packages limma, ggplot2, and pheatmap. Coex-pression analysis was used to define the correlations betweenthe expression levels of nine key ceRNAs and those of theeight immune-checkpoint genes. A two-gene correlationmap was obtained using the R package ggstatsplot. A P valueof less than 0.05 was considered to indicate statistical signif-icance. The Tumor Immune Dysfunction and Exclusion(TIDE, http://tide.dfci.harvard.edu) algorithm was then usedto estimate the predictive power of the custom biomarkerwith respect to response outcome and OS [28]. We con-firmed the correlations between the eight key mRNAs andresponse to ICIs in other cancers using TIDE.
2.7. Correlations between Expression of Key ceRNAs andDrug Sensitivity. Gene Set Cancer Analysis (GSCALite,http://bioinfo.life.hust.edu.cn/web/GSCALite/) is a webserver for dynamic analysis and visualization of gene setsin cancer and drug sensitivity correlations. The expressionof each gene in the gene set was determined, and small mol-ecule/drug sensitivity (half-maximal inhibitory concentra-tion; IC50) was obtained using Spearman’s correlationanalysis. Correlations with FDR < 0:05 were considered torepresent results [29–31]. We used GSCALite to analyzethe correlations between drug sensitivity and the signatureof nine key ceRNAs.
2.8. Validation of Results. LOGpc (Long-term Outcome andGene Expression Profiling Database of pan-cancers, http://bioinfo.henu.edu.cn/DatabaseList.jsp) includes 209 geneexpression datasets and provides 13 types of survival termsfor 31,310 patients with 27 distinct malignancies [32]. Wefirst confirmed the prognostic value of major target genesusing LOGpc datasets. Next, we confirmed the prognosticvalue of key immune cell types and ceRNAs using theTIMER 2.0 database [33]. Finally, we confirmed the expres-sion of eight immune-checkpoint genes and determined thecorrelations between the expression levels of these genes and
nine key genes in HNSCC with different HPV statuses usingthe gene correlation TIMER 2.0 module (http://timer.cistrome.org/) [34].
2.9. Statistical Analysis. All statistical analyses were carriedout using R (version 3.6.3, https://www.r-project.org/) andthe limma, GDCRNATools, ggplot2, rms, glmnet, survmi-ner, and timeROC packages. A two-sided P value of less than0.05 was considered to indicate statistical significance.
3. Results
3.1. Identification of Differentially Expressed Genes,DEmiRNAs, and DElncRNAs. We identified 115 DElncR-NAs, 166 DEmiRNAs, and 2221 DEmRNAs using theDESeq2 package in the R programming language. Of these,115 lncRNAs, 182 miRNAs, and 2213 mRNAs were foundto be differentially expressed in HNSCC using the edgeRmethod. Next, we acquired 109 DElncRNAs, 169 DEmiR-NAs, and 2069 DEmRNAs using the R package limma. Atotal of 95 DElncRNAs, 146 DEmiRNAs, and 1746 DEmR-NAs were identified using three independent methods(Figures 1(a)–1(f)).
3.2. Construction of ceRNA Network and Survival Analysis.We constructed a lncRNA–miRNA–mRNA ceRNA net-work, which included three lncRNAs, eight miRNAs, and69 mRNAs (Figure 1(g)). Then, Kaplan–Meier (K-M) sur-vival analysis was performed to identify prognostic membersin the constructed ceRNA network. Our results showed that10 key markers, including ACSL1, CDCA4, GNA12, hsa-miR-29c-3p, hsa-miR-130b-3p, ITGA5, KDELC1, PRKAA2,PRUNE2, and PTX3, were significantly correlated with sur-vival (Figures 2(a)–2(j)).
3.3. Construction of ceRNA-Related Prognostic Model. Thir-teen ceRNAs were identified as prognosis-related signaturesusing univariate Cox regression (Table 1). LASSO regressionanalysis revealed that nine key markers were essential formodeling (Figures 3(a) and 3(b)); these were subjected to
Table 1: Identification of prognosis-related ceRNAs by univariate Cox regression analysis.
Id HR HR.95L HR.95H P value
ANLN 1.2194 1.0487 1.4179 0.0099
C1QTNF6 1.1279 1.0083 1.2617 0.0354
CFL2 1.2049 1.0554 1.3756 0.0058
DCBLD2 1.1560 1.0149 1.3166 0.0290
GNA12 1.3001 1.0687 1.5816 0.0087
ITGA5 1.2156 1.0892 1.3567 0.0005
KDELC1 1.3339 1.1295 1.5753 0.0007
KIF23 1.2437 1.0289 1.5034 0.0242
NFIA 0.7776 0.6488 0.9319 0.0065
PRUNE2 1.0667 1.0078 1.1292 0.0260
PTX3 1.1174 1.0509 1.1882 0.0004
RELT 1.2274 1.0165 1.4822 0.0332
TMC7 1.1395 1.0046 1.2926 0.0422
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−7 −6 −5 −4 −3
−0.20
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−0.05
0.00
0.05
0.10
0.15
Log lambda
Coef
ficie
nts
13 13 12 9 7
1
2
3
4
5
67
8
9
10
11
12
13
(a)
−7 −6 −5 −4 −3
12.15
12.20
12.25
12.30
12.35
12.40
12.45
Log (𝜆)
Part
ial l
ikel
ihoo
d de
vian
ce
13 13 13 13 13 13 11 9 9 9 8 8 7 5 3
(b)
Figure 3: Continued.
13BioMed Research International
TMC7
RELT
PTX3
NFIA
KIF23
KDELC1
ITGA5
CFL2
ANLN
(N = 493)
(N = 493)
(N = 493)
(N = 493)
(N = 493)
(N = 493)
(N = 493)
(N = 493)
(N = 493)
1.05(0.90 − 1.22)
1.13(0.91 − 1.40)
1.08(1.00 − 1.16)
0.82(0.67 − 0.99)
1.16(0.88 − 1.54)
1.08(0.87 − 1.35)
1.01(0.86 − 1.19)
1.10(0.94 − 1.28)
1.04(0.81 − 1.33)
0.567
0.267
0.046 ⁎
0.044 ⁎
0.301
0.466
0.858
0.234
0.76
# Events: 215; global p-value (log-rank): 0.00029134 AIC: 2320.19; concordance index: 0.63
0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6
Hazard ratio
(c)
0.0 0.2 0.4 0.6 0.8 1.0
0.0
0.2
0.4
0.6
0.8
1.0
1 − specificity
Sens
itivi
ty
AUC at 1 years: 0.633AUC at 3 years: 0.681AUC at 5 years: 0.591
(d)
Figure 3: Continued.
14 BioMed Research International
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++ +
+
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++ ++++ +++ ++ ++
+p < 0.001
0.00
0.25
0.50
0.75
1.00
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Time (years)
Surv
ival
pro
babi
lity
RiskHigh risk
Low risk
246169 86 50 30 17 9 6 4 3 2 2 2 1 1 0 0 0 0 0 0247204128 83 62 35 25 20 12 10 9 7 5 5 3 2 1 1 0 0 0Low risk
High risk
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Time (years)
Risk
+
+
(e)
Age
Gender
Grade
Stage
T
N
Risk score
0.220
0.102
0.049
0.003
0.004
<0.001
<0.001
pvalue
1.014 (0.991 − 1.038)
0.622 (0.352 − 1.099)
1.517 (1.002 − 2.298)
1.967 (1.263 − 3.063)
1.518 (1.141 − 2.018)
1.827 (1.362 − 2.451)
2.665 (1.606 − 4.422)
Hazard ratio
Hazard ratio0 1 2 3 4
(f)
Figure 3: Continued.
15BioMed Research International
multivariable model analysis. Only two key biomarkers(NFIA and PTX3) had a significant impact on HNSCC prog-nosis (Figure 3(c)). In addition, analysis of the ROC curvesindicated that the AUCs for 1-, 3-, and 5-year OS were0.633, 0.681, and 0.591, respectively (Figure 3(d)). We fur-ther plotted survival curves for the high- and low-riskgroups. As shown in Figure 3(e), patients in the low-riskgroup had significantly longer OS probability than those inthe high-risk group. Finally, univariate and multivariateCox regression analyses demonstrated that the risk scorebased on key ceRNAs was an independent predictor of poorprognosis in HNSCC patients (Figures 3(f) and 3(g)).
3.4. Immune Cell Infiltration Analysis. CIBERSORTwas usedto assess immune cell infiltration in each HNSCC sample.The results revealed significant differences in the proportionsof immune cell infiltration (Figure 4(a)). In addition, the gen-erated heatmap showed that 11 immune cell subtypes, M1macrophages, CD8 T cells, M0 macrophages, M2 macro-phages, resting CD4 memory T cells, memory B cell, naïveB cells, and regulatory T cells (Treg), monocytes, restingmyeloid dendritic cells, and activated mast cells presentedsignificant different proportions between the tumor groupand the normal group (Figure 4(b)).
3.5. Construction and Validation of Immune Cell-RelatedPrognostic Model. Univariate Cox regression, LASSO regres-sion, multivariate Cox regression, and independent prognos-tic analysis were used to analyze the associations betweendifferent immune cell subtypes and prognosis. The resultsshowed that three variables were related to prognosis inHNSCC: high infiltration of Tregs and naïve B cells wasassociated with a favorable prognosis, whereas increasedlevels of neutrophils were correlated with worse prognosis(Figures 4(c)–4(e)). According to ROC curve analysis, the
AUCs of the 1-, 3-, and 5-year prognosis models were0.625, 0.626, and 0.568, respectively (Figure 4(f)). The K-Mcurve analysis indicated that the high-risk group had anunfavorable prognosis (Figure 4(g)). Finally, we found thatthe immune cell-related risk score was an independentfactor for predicting prognosis in HNSCC (Figures 4(h)and 4(i)).
3.6. Relationships between Key ceRNAs and SignificantImmune Cell Signatures. There were significant correlationsbetween key molecules in the ceRNA network and immunecell signatures (Figure 5(a)). The coexpression analysisresults indicated that CFL2, ITGA5, KDELC1, and TMC7were negatively associated with levels of naïve B cell infiltra-tion (Figures 5(b)–5(e)), whereas ANLN, ITGA5, KIF23,and TMC7 expression was negatively associated with Treglevels (Figures 5(f)–5(i)). As shown in Figures 5(j)–5(l), sig-nificant immune cell signatures in different risk score exhib-ited statistical significance, and higher levels of naïve B cellswere associated with lower risk scores (P = 0:0085). A simi-lar result was observed for Tregs (P = 4e − 9).
3.7. Clinical Correlation Analysis. We evaluated the correla-tions of the nine key signatures with tumor grade and stage.Our results showed that increased expression of ANLN andKIF23 was associated with higher tumor grade (Figures 6(a)and 6(b)). Moreover, the expression levels of ITGA5,KDELC1, and PTX3 were positively correlated with the stageof HNSCC, whereas NFIA expression decreased at higherHNSCC stages (Figures 6(c)–6(f)). Furthermore, our resultsshowed that ANLN, KDELC1, KIF23, and NFIA expressionwas associated with different immune subtypes. ANLN andKIF23 showed increased expression in subtypes C1 andC2. KDELC1 showed higher expression in the C1, C2, andC6 subtypes, indicating that it may be mainly associated
Age
Gender
Grade
Stage
T
N
Risk score
0.824
0.137
0.093
0.793
0.039
0.002
0.004
pvalue
1.003 (0.978 − 1.028)
0.640 (0.355 − 1.153)
1.497 (0.936 − 2.395)
0.914 (0.465 − 1.794)
1.562 (1.023 − 2.386)
1.717 (1.213 − 2.430)
2.184 (1.281 − 3.724)
Hazard ratio
Hazard ratio0.0 1.0 2.0 3.0
(g)
Figure 3: Development and validation of the ceRNA-related prognostic model. (a–c) LASSO and multivariate Cox regression analyses wereapplied to investigate the correlation between OS and ceRNAs. (d) ROC analysis showing the accuracy of the prediction model. (e) K-Msurvival curves comparing the high-risk and low-risk groups and the demonstrating predictive ability of our model. (f, g) Assessment ofthe independence of ceRNA-related prognostic model through (f) univariate and (g) multivariate Cox regression analyses. HR > 1 and Pvalue < 0.05 indicate poor prognostic factors. HR < 1 and P values < 0.05 indicate favorable prognostic factors.
16 BioMed Research International
100%
50%
Perc
ent
0%Type
B cell memory
B cell naive
B cell plasma
Eosinophil
Macrophage M0
Macrophage M1
Macrophage M2
Mast cell activated
Mast cell resting
Monocyte
Myeloid dendritic cell activated
Myeloid dendritic cell resting
Neutrophil
NK cell activated
NK cell resting
T cell CD4+ memory activated
T cell CD4+ memory resting
T cell CD4+ naive
T cell CD8+
T cell follicular helper
T cell gamma delta
T cell regulatory (tregs)
(a)
Figure 4: Continued.
17BioMed Research International
GroupsMacrophage M1⁎⁎⁎ 9.00e–07 2
–2
5.83e–039.04e–025.49e–017.07e–018.02e–212.64e–015.31e–019.09e–021.25e–012.48e–029.29e–072.37e–034.53e–031.52e–033.90e–011.48e–011.31e–012.79e–147.94e–019.64e–073.66e–07
T cell CD8+⁎⁎T cell CD4+ memory activatedT cell follicular helperNK cell activatedMacrophage M0⁎⁎⁎B cell plasmaMyeloid dendritic cell activatedNK cell restingMast cell restingMacrophage M2⁎T cell CD4+ memory resting⁎⁎⁎B cell memory⁎⁎T cell regulatory (tregs)⁎⁎B cell naive⁎⁎T cell gamma deltaT cell CD4+ naiveEosinophilMonocyte⁎⁎⁎NeutrophilMyeloid dendritic cell resting⁎⁎⁎Mast cell activated⁎⁎⁎
1
0
–1
GroupsTumorNormal
(b)
−6 −5 −4 −3
−15
−10
−5
0
5
10
15
20
Log lambda
Coeffi
cien
ts
5 5 5 5
1
2
3
4
5
(c)
Figure 4: Continued.
18 BioMed Research International
−6 −5 −4 −3
11.7
11.8
11.9
12.0
Log (𝜆)
Part
ial l
ikel
ihoo
d de
vian
ce
5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 3 2 0
(d)
Neutrophils
T cells regulatory (tregs)
B cells naive
(N= 338)
(N= 338)
(N= 338)
6.2e+03(2.5e+00 − 1.5e+07)
7.9e−08(4.1e−15 − 1.5e+00)
4.6e−02(2.4e−03 − 8.9e−01)
0.029⁎
0.056
0.042⁎
# Events: 144; global p-value (log-rank): 0.00099182AIC: 1438.2; concordance index: 0.61
1e−16 1e−12 1e−08 0.0001 1 10000 1e+08
Hazard ratio
(e)
Figure 4: Continued.
19BioMed Research International
0.0 0.2 0.4 0.6 0.8 1.0
0.0
0.2
0.4
0.6
0.8
1.0
1 − specificity
Sens
itivi
ty
AUC at 1 years: 0.625AUC at 3 years: 0.626AUC at 5 years: 0.568
(f)
++++
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++ +
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++ ++++
++ +
p = 0.015
0.00
0.25
0.50
0.75
1.00
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Time (years)
Surv
ival
pro
babi
lity
169126 64 42 28 15 7 5 5 4 3 3 3 2 2 1 0 0 0 0 0169134 87 56 37 21 14 11 7 6 5 4 3 3 1 1 1 1 0 0 0Low risk
High risk
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Time (years)
Risk
RiskHigh risk
Low risk
+
+
(g)
Figure 4: Continued.
20 BioMed Research International
with worse survival. NFIA showed higher expression in sub-type C3 and decreased expression in C4, which predictedbetter survival (Figures 6(g)–6(i)). CFL2, ITGA5, KDELC1,and PTX3 were highly expressed in the MS subtype.Increased expression of RLET and TMC7 was mainly foundin the basal subtype, and higher expression of NFIA wasassociated with the AT subtype (Figures 6(k)–6(q)).
3.8. Key ceRNA Expression Was Correlated withImmunotherapy Response and Drug Sensitivity. Multiple ICgenes including CD274, CTLA4, HAVCR2, LAG3, PDCD1,SIGLEC15, TIGIT, and TIM3 exhibited higher expression intumor tissues compared with normal tissues (Figure 7(a)).The expression of ANLN, ITGA5, and KIF23 was positivelyassociated with the expression of CD274 (PDL1), HAVCR2,and SIGLEC15. CFL2 and RELT expression was positivelycorrelated with the expression of CD274 (PDL1), CTLA4,HAVCR2, LAG3, PDCD1 (PD1), SIGLEC15, and TIGIT.
NFIA was positively related to the abovementioned sevenimmunosuppressive genes, except for CD274. Overexpressionof PTX3 was associated with increased CTLA4, HAVCR2,SIGLEC15, and TIGIT expression. TMC7 expression wasnegatively correlated with the expression of CTLA4,HAVCR2, LAG3, PDCD1 (PD1), and TIGIT (Figure 7(b)).
In addition, our biomarker could effectively predict anti-PD1 response compared with published biomarkers (MSI,CD274, CD8, IFNG, etc.) (Figure 7(c)). Moreover, Spear-man’s correlation analysis was performed to explore the cor-relations of the expression of the nine key genes with drugsensitivity in terms of IC50 values. Our results showed thatmost drugs were effective in association with increasedexpression of CFL2, TMC7, PTX3, ANLN, NFIA, andKIF23, whereas RELT and ITGA5 were negatively regulatedby most drugs. Specifically, these molecules could beexploited as potential therapeutic drug targets for HNSCC(Figure 7(d)).
Age
Gender
Grade
Stage
T
N
Risk score
0.670
0.191
0.125
0.025
0.010
<0.001
0.029
pvalue
1.006 (0.979 − 1.034)
0.637 (0.325 − 1.251)
1.464 (0.900 − 2.383)
1.715 (1.071 − 2.747)
1.556 (1.111 − 2.179)
1.918 (1.346 − 2.734)
1.738 (1.057 − 2.858)
Hazard ratio
Hazard ratio0.0 0.5 1.0 1.5 2.0 2.5
(h)
Age
Gender
Grade
Stage
T
N
Risk score
0.762
0.102
0.011
0.054
0.005
<0.001
0.006
pvalue
0.996 (0.968 − 1.024)
0.562 (0.281 − 1.122)
2.183 (1.194 − 3.992)
0.466 (0.215 − 1.012)
2.171 (1.261 − 3.735)
2.543 (1.631 − 3.964)
2.398 (1.281 − 4.488)
Hazard ratio
Hazard ratio0 1 2 3 4
(i)
Figure 4: Construction and validation of the immune cells related prognostic model. (a) Distribution of 22 immune cell subtypes estimatedby CIBERSORT in HNSCC. (b) Heatmap showing the levels of 22 immune cell subtypes in tumor and normal samples. (c–e) LASSO andmultivariate Cox regression were used to investigate the correlation between OS and immune cell infiltration. (f, g) ROC and Kaplan–Meiersurvival curves showing the accuracy of immune cell subtypes and related prognostic models for predicting OS. (h) Univariate analysis and(i) multivariate Cox regression analysis confirmed the independence of the immune cell-related prognostic model.
21BioMed Research International
−1
−0.8
−0.6
−0.4
−0.2
0
0.2
0.4
0.6
0.8
1A
NLN
CFL2
ITG
A5
KDEL
C1
KIF2
3
NFI
A
PTX3
RELT
TMC7
B ce
lls n
aive
T ce
lls re
gulat
ory
(treg
s)
Neu
troph
ils
ANLN
CFL2
ITGA5
KDELC1
KIF23
NFIA
PTX3
RELT
TMC7
B cells naive
T cells regulatory (tregs)
Neutrophils
1
0.26
0.32
0.24
0.75
0.11
0.09
0.28
0.25
−0.1
−0.25
0.05
0.26
1
0.43
0.3
0.15
−0.05
0.26
0.11
0.11
−0.24
−0.14
0
0.32
0.43
1
0.56
0.11
−0.14
0.41
0.32
0.48
−0.33
−0.29
0.04
0.24
0.3
0.56
1
0.14
−0.22
0.41
0.15
0.32
−0.18
−0.17
0.03
0.75
0.15
0.11
0.14
1
0.03
−0.04
0.19
0.09
−0.06
−0.22
−0.01
0.11
−0.05
−0.14
−0.22
0.03
1
−0.05
−0.05
−0.01
0.16
0.11
−0.05
0.09
0.26
0.41
0.41
−0.04
−0.05
1
0.19
0.07
−0.01
−0.12
0.04
0.28
0.11
0.32
0.15
0.19
−0.05
0.19
1
0.29
−0.12
−0.13
0.11
0.25
0.11
0.48
0.32
0.09
−0.01
0.07
0.29
1
−0.21
−0.29
0.14
−0.1
−0.24
−0.33
−0.18
−0.06
0.16
−0.01
−0.12
−0.21
1
0.23
0.04
−0.25
−0.14
−0.29
−0.17
−0.22
0.11
−0.12
−0.13
−0.29
0.23
1
−0.08
0.05
0
0.04
0.03
−0.01
−0.05
0.04
0.11
0.14
0.04
−0.08
1
(a)
Figure 5: Continued.
22 BioMed Research International
R = −0.24, p = 1.1e−05
0.0
0.1
0.2
0.3
2 4 6CFL2
B ce
lls n
aive
(b)
R = −0.33, p = 9e−10
0.0
0.1
0.2
0.3
4 6 8 10ITGA5
B ce
lls n
aive
(c)
Figure 5: Continued.
23BioMed Research International
R = −0.18, p = 0.00099
0.0
0.1
0.2
0.3
0 2 4KDELC1
B ce
lls n
aive
(d)
R = −0.21, p = 8e−05
0.0
0.1
0.2
0.3
0 2 4TMC7
B ce
lls n
aive
(e)
Figure 5: Continued.
24 BioMed Research International
R = −0.25, p = 4.1e−06
0.00
0.02
0.04
0.06
0.08
3 4 5 6 7 8ANLN
T ce
lls re
gulat
ory
(treg
s)
(f)
R = −0.29, p = 6.3e−08
0.00
0.02
0.04
0.06
0.08
4 6 8 10ITGA5
T ce
lls re
gulat
ory
(treg
s)
(g)
Figure 5: Continued.
25BioMed Research International
R = −0.22, p = 6.3e−05
0.00
0.02
0.04
0.06
0.08
3 4 5 6KIF23
T ce
lls re
gulat
ory
(treg
s)
(h)
R = −0.29, p = 5.7e−08
0.00
0.02
0.04
0.06
0.08
0 2 4TMC7
T ce
lls re
gulat
ory
(treg
s)
(i)
Figure 5: Continued.
26 BioMed Research International
0.0085
0.0
0.1
0.2
0.3
High risk Low riskRisk
B ce
lls n
aive
RiskHigh risk
Low risk
(j)
0.22
0.00
0.05
0.10
0.15
High risk Low riskRisk
Neu
trop
hils
RiskHigh risk
Low risk
(k)
Figure 5: Continued.
27BioMed Research International
3.9. Validation of the Prognostic Value of Biomarkers andAssociations between Key ceRNAs and IC Genes. LOGpcwas used to perform survival analysis for key ceRNAs. Theresults indicated that higher expression levels of CFL2,ITGA5, KDELC1, PTX3, and RELT were correlated withpoor prognosis in HNSCC patients, whereas increasedexpression of NFIA was associated with longer OS. Therewas no correlation between ANLN, KIF23, or TMC7 expres-sion and prognosis in HNSCC patients (Table 2). The asso-ciations between pivotal ceRNAs and prognosis were thendetermined using TIMER 2.0. We found that high expres-sion levels of ANLN, CFL2, ITGA5, KDELC1, PTX3, RELT,and TMC7 were significantly associated with shorter OS inHNSCC patients, whereas higher expression of NFIA wascorrelated with longer OS. In HPV-positive HNSCCpatients, high expression of ITGA5, KDELC1, and TMC7was associated with poor prognosis, whereas high NFIAexpression was correlated with good prognosis. ANLN,CFL2, KDELC1, PTX3, and RELT were associated with unfa-vorable prognosis in HPV-negative HNSCC (Figure 8(a)). Inaddition, the prognostic roles of immune cells in HNSCCpatients with different HPV statuses were confirmed usingthe TIMER 2.0 database. In both HPV-positive and HPV-negative HNSCC patients, high infiltration levels of naïveB cells and Tregs were associated with a favorable progno-sis according to several algorithms, whereas high neutro-phil infiltration indicated an unfavorable prognosis(Figures 8(b)–8(d)). Eight tumor-related immunosuppres-
sive molecules, CD274, CTLA4, HAVCR2, LAG3, PDCD1(PD1), PDCD1LG2, SIGLEC15, and TIGIT, had higherexpression in HNSCC tumor tissues compared with HNSCCnormal tissues.
Notably, most IC molecules showed significantlyincreased expression in HPV-positive HNSCC patients(Figure 8(e)). We also found that the expression of theseICI factors was significantly positively correlated with theexpression of seven key mRNAs (ANLN, CFL2, ITGA5,KIF23, NFIA, PTX3, and RELT), whereas the expression ofimmunosuppressive molecules was negatively associatedwith TMC7 expression, especially in HPV-positive HNSCCpatients (Figure 8(f)). We further discovered that eight keyceRNAs were correlated with response to ICI in othercancers (melanoma, bladder, kidney, and glioblastoma)(Table 3).
These results are consistent with the results of our study.
4. Discussion
HNSCC is among the deadliest malignancies in humans anda significant cause of cancer-related deaths worldwide [35].Despite advances in the screening, diagnosis, and treatmentof HNSCC in recent decades, especially in terms of immuno-therapy, the prognosis of HNSCC patients remains verypoor [36]. Recent studies have explored the roles of immunecell infiltration and ceRNA networks in HNSCC. However,these studies have failed to accurately identify key molecules
4e−09
0.00
0.02
0.04
0.06
0.08
High risk Low riskRisk
T ce
lls re
gulat
ory
(treg
s)
RiskHigh risk
Low risk
(l)
Figure 5: Analysis of the correlations of significant genes in the ceRNA network and gene risk score with immune cell infiltration. (a)Heatmap displaying correlations between prognostic immune cells and key genes in the ceRNA network. (b–e) Expression of CFL2,ITGA5, KDELC1, and TMC7 was negatively associated with infiltration of naïve B cells. (f–i) ANLN, ITGA5, KIF23, and TMC7expression was negatively associated with Tregs. (j–l) Pearson’s correlation analysis was performed to evaluate the associations betweenkey immune cells and gene risk score.
28 BioMed Research International
3
G1
G2
G3
G4
Gra
de
4 5 6ANLN
7 8
(a)
2.5
G1
G2
G3
G4
Gra
de3.0 3.5
KIF236.56.05.55.04.54.0
(b)
9 10
Stage I
Stage II
Stage III
Stage IV
Stag
e
4 5 6ITGA5
7 8
(c)
Figure 6: Continued.
29BioMed Research International
5
Stage I
Stage II
Stage III
Stage IV
Stag
e
0 1 2KDELC1
3 4
(d)
6
Stage I
Stage II
Stage III
Stage IV
Stag
e
1 2 3NFIA
4 5
(e)
Figure 6: Continued.
30 BioMed Research International
4 6
Stage I
Stage II
Stage III
Stage IV
Stag
e
–6 –4 –2PTX3
0 2
(f)
8
6
4
Expr
essio
n (lo
g2CP
M)
2
C1 C2 C3
HNSC :: ANLN_expPv = 3.51e–02
n = C1 128, C2 379, C3 2, C4 2, C6 3
SubtypeC4 C6
(g)
8
6
4
Expr
essio
n (lo
g2CP
M)
2
C1 C2 C3
HNSC :: ANLN_expPv = 3.51e–02
n = C1 128, C2 379, C3 2, C4 2, C6 3
SubtypeC4 C6
(h)
8
6
4
Expr
essio
n (lo
g2CP
M)
2
C1 C2 C3
HNSC :: ANLN_expPv = 3.51e–02
n = C1 128, C2 379, C3 2, C4 2, C6 3
SubtypeC4 C6
(i)
6
8
4
Expr
essio
n (lo
g2CP
M)
2
C1 C2 C3
HNSC :: NFIA_expPv = 3.78e–03
n = C1 128, C2 379, C3 2, C4 2, C6 3
SubtypeC4 C6
(j)
8
6
4
Expr
essio
n (lo
g2CP
M)
2
C1 C2 C3
HNSC :: ANLN_expPv = 3.51e–02
n = C1 128, C2 379, C3 2, C4 2, C6 3
SubtypeC4 C6
(k)
Figure 6: Continued.
31BioMed Research International
7.5
10.0
5.0
Expr
essio
n (lo
g2CP
M)
2.5
Atyp
ical
HNSC :: ITGA5_expPv = 2.24e–23n = atypical 67,
basal 87,classical 48,
mesenchymal 74
Subtype
Basa
l
Clas
sical
Mes
ench
ymal
(l)
7.5
10.0
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Expr
essio
n (lo
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Atyp
ical
HNSC :: ITGA5_expPv = 2.24e–23n = atypical 67,
basal 87,classical 48,
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Subtype
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l
Clas
sical
Mes
ench
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(m)
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essio
n (lo
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HNSC :: NFIA_expPv = 3.43e–07n = atypical 67,
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mesenchymal 74
Subtype
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l
Clas
sical
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ench
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(n)
0
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n (lo
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Atyp
ical
HNSC :: PTX3_expPv = 2.06e–11n = atypical 67,
basal 87,classical 48,
mesenchymal 74
Subtype
Basa
l
Clas
sical
Mes
ench
ymal
(o)
Figure 6: Continued.
32 BioMed Research International
for predicting the prognosis of HNSCC [9, 10, 37]. Accumu-lating evidence suggests that machine learning is a reliableand robust technique that can be used to quickly and accu-rately identify critical biomarkers [38, 39]. ICIs may exertbeneficial therapeutic effects in HNSCC, although theresponse rate to ICIs remains poor [15]. A lncRNA signatureof tumor-infiltrating B lymphocytes was found to havepotential applications in prognostic prediction and immu-notherapy for bladder cancer based on computational recog-nition [40], and lncRNAs associated with tumor immuneinfiltration were identified as improving clinical outcomesand immunotherapy response in non-small-cell lung cancerbased on comprehensive analysis [41]. Combinations ofceRNA with ICIs and TIICs for improving prognosis andimmunotherapy response in HNSCC are limited. Therefore,it is crucial to establish predictive biomarkers for selectingpatients who will be responsive to ICI therapy.
In the present study, we defined nine key ceRNAs(ANLN, CFL2, ITGA5, KDELC1, KIF23, NFIA, PTX3,RELT, and TMC7) and three immune cell subtypes (naïveB cells, Tregs, and neutrophils) using univariate Coxanalysis, LASSO, multivariate Cox analysis, and independentprognostic analysis. Specifically, KDELC1, PTX3, andITGA5 were found to be associated with poor prognosis inboth the K-M survival analysis and the multivariate Coxanalysis. ROC curve analysis was used to further evaluateboth signatures and confirm their favorable predictive andprognostic abilities.
We identified a potential regulatory mechanism involv-ing KCNQ1OT1 (lncRNA), miR-338-3p (miRNA)/miR-29c-3p, ITGA5 (mRNA)/KDELC1, and naïve B cells/Tregs.
A previous report indicated that KCNQ1OT1 was asso-ciated with cell proliferation, apoptosis, prognosis, invasion,and metastasis in various cancers [10, 42–44]. Further,KCNQ1OT1 facilitated invasion and inhibited apoptosis inoral squamous cell carcinoma by regulating the miR-185-5p/Rab14 axis [45]. miR-338-3p was downregulated inesophageal squamous cell carcinoma and could act as atumor suppressor [46]. In addition, miR-338-3p was shownto inhibit colorectal carcinoma cell invasion and migrationby targeting smoothened [47] and was associated with favor-able prognosis in urothelial carcinoma of the bladder [48].Inhibition of miR-29c-3p was found to be associated withpoor prognosis in patients with laryngeal squamous cell car-cinoma [49]. ITGA5 has essential roles in tumorigenesis,migration, and invasion in various cancer types [10]. Studieshave shown that ITGA5 is highly expressed in HNSCC,where its high expression is significantly associated withpoor survival [50]. Overexpression of PTX3 has been relatedto poor prognosis in pancreatic cancer and is linked to moreadvanced stages of the disease [51]. Evidence also suggeststhat PTX3 promotes metastasis of cervical cancer andEGF-induced metastasis of HNSCC through upregulationof MMP-2 and MMP-9 [52]. Our results are in accordancewith these findings and suggest that the KCNQ1OT1/miR-338-3p/ITGA5 and KCNQ1OT1/miR-29c-3p/KDELC1 axes
4
6
8Ex
pres
sion
(log2
CPM
)
2
Atyp
ical
HNSC :: RELT_expPv = 1.39e–04n = atypical 67,
basal 87,classical 48,
mesenchymal 74
Subtype
Basa
l
Clas
sical
Mes
ench
ymal
(p)
0.0
2.5
5.0
Expr
essio
n (lo
g2CP
M)
–2.5
Atyp
ical
HNSC :: TMC7_expPv = 6.62e–09n = atypical 67,
basal 87,classical 48,
mesenchymal 74
Subtype
Basa
l
Clas
sical
Mes
ench
ymal
(q)
Figure 6: Clinical correlation analysis. (a, b) ANLN and KIF23 expression was associated with tumor grade according to TISIDB datasets.(a) ANLN and (b) KIF23. (c–f) Key mRNAs among ceRNAs related to tumor stage according to TISIDB. (c) ITGA5, (d) KDELC1, (e) NFIA,and (f) PTX3. (g–i) Distribution of the expression of key ceRNAs across immune subtypes according to TISIDB: (g) ANLN, (h) KDELC1, (i)KIF23, and (j) NFIA. (k–q) Distribution of key ceRNA expression across molecular subtypes (TISIDB): (k) CFL2, (l) ITGA5, (m) KDELC1,(n) NFIA, (o) PTX3, (p) RELT, and (q) TMC7. Statistical significance of differential expression evaluated using Kruskal–Wallis test. C1(wound healing), C2 (IFN-gamma dominant), C3 (inflammatory), C4 (lymphocyte depleted), and C6 (TGF-β dominant). Molecularsubtypes include four types, namely, atypical (AT), basal (BA), classical (CL), and mesenchymal (MS) based on biological characteristicsof genes highly expressed in each subtype.
33BioMed Research International
⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎
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Correlation
(b)
Figure 7: Continued.
34 BioMed Research International
Custo
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(d)
Figure 7: Key ceRNA expression correlates with immunotherapy response and drug sensitivity. (a) Differences in expression of tumor-related immunosuppressive molecules in HNSCC; ∗P < 0:05, ∗∗P < 0:01, and ∗∗∗P < 0:001. (b) Correlations between key ceRNAs and ICmolecules. The horizontal and vertical coordinates represent genes. Different colors represent correlation coefficients (blue, positivecorrelation and red, negative correlation); the darker the color, the stronger the correlation; ∗P < 0:05 and ∗∗P < 0:01. (c) Comparison ofAUC values between the custom biomarker and other published biomarkers in predicting anti-PD1 response. (d) Correlation analysis ofdrug sensitivity and expression of key ceRNAs.
Table 2: Survival analysis for major target ceRNAs using LOGpc.
Symbol Dataset HR 95% CI P value Prognostic
CFL2 TCGA 1.3608 1.0137-1.8268 0.0403 Poor
ITGA5 GSE31056 2.6804 1.3752-5.2245 0.0038 Poor
ITGA5 TCGA 1.4878 1.1162-1.9832 0.0067 Poor
KDELC1 TCGA 1.4946 1.1212-1.9922 0.0061 Poor
KDELC1 GSE31056 2.1694 1.0960-4.2940 0.0262 Poor
NFIA GSE65858 0.4627 0.2648-0.8086 0.0068 Good
PTX3 GSE31056 3.9765 2.0435-7.7379 <0.0001 Poor
PTX3 TCGA 1.3605 1.0103-1.8320 0.0426 Poor
RELT TCGA 1.3554 1.0113-1.8165 0.0418 Poor
35BioMed Research International
Decreased risk (P < 0.05, Z > 0)Increased risk (P < 0.05, Z > 0)Not significant (P > 0.05)
HNSC (n = 522) ANLN
HNSC-HPV+ (n = 98) TMC7
Cancer Gene P z_score0.0520 1.9431
0.0000 4.2508
HNSC-HPV– (n = 422)HNSC-HPV+ (n = 98)HNSC (n = 522)HNSC-HPV– (n = 422)HNSC-HPV+ (n = 98)HNSC (n = 522)HNSC-HPV– (n = 422)HNSC-HPV+ (n = 98)HNSC (n = 522)HNSC-HPV– (n = 422)HNSC-HPV+ (n = 98)HNSC (n = 522)HNSC-HPV– (n = 422)HNSC-HPV+ (n = 98)HNSC (n = 522)HNSC-HPV– (n = 422)HNSC-HPV+ (n = 98)HNSC (n = 522)HNSC-HPV– (n = 422)HNSC-HPV+ (n = 98)HNSC (n = 522)HNSC-HPV– (n = 422)HNSC-HPV+ (n = 98)HNSC (n = 522)HNSC-HPV– (n = 422)
ANLNANLNCFL2CFL2CFL2
ITGA5ITGA5ITGA5
KDELC1KDELC1KDELC1
KIF23KIF23KIF23NFIANFIANFIAPTX3PTX3PTX3RELTRELTRELTTMC7TMC7
0.04720.42890.01000.01140.31960.00030.05290.00010.00210.03000.00670.15380.05080.87770.00060.08150.00010.00090.00270.16220.09490.03260.38730.04330.7202
1.98440.79102.57452.53130.99523.61161.93554.02233.07992.17032.71111.42611.95310.1539
–3.4135–1.7420–3.81623.33593.00461.39771.66992.1370
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(a)
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switc
hed
mem
ory
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ll_XC
ELL
(b)
Figure 8: Continued.
36 BioMed Research International
p > 0.05
p ≤ 0.05
HNSC (n = 522)
Zscore4.7
0.0
–4.1
Neu
troph
il_TI
MER
HNSC-HPV– (n = 422)
HNSC-HPV+ (n = 98)
Neu
troph
il_CI
BERS
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-ABS
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0.0
–4.1
T ce
ll re
gulat
ory
(treg
s)_C
IBER
SORT
HNSC-HPV– (n = 422)
HNSC-HPV+ (n = 98)
T ce
ll re
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ory
(treg
s)_C
IBER
SORT
-ABS
T ce
ll re
gulat
ory
(treg
s)_Q
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TISE
Q
T ce
ll re
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ory
(treg
s)_X
CELL
(d)
CD274
CTLA4
HAVCR2
LAG3
PDCD1
PDCD1LG2
SIGLEC15
TIGIT
HNSC.normalHNSC-HPVpos.tumorHNSC-HPVneg.tumor
HNSC.tumor
HNSC.tumor
HNSC.normalHNSC-HPVpos.tumorHNSC-HPVneg.tumor
HNSC.tumorHNSC.normal
HNSC-HPVpos.tumorHNSC-HPVneg.tumor
HNSC.tumorHNSC.normal
HNSC-HPVpos.tumorHNSC-HPVneg.tumor
HNSC.tumorHNSC.normal
HNSC-HPVpos.tumorHNSC-HPVneg.tumor
HNSC.tumorHNSC.normal
HNSC-HPVpos.tumorHNSC-HPVneg.tumor
HNSC.tumorHNSC.normal
HNSC-HPVpos.tumorHNSC-HPVneg.tumor
HNSC.tumorHNSC.normal
HNSC-HPVpos.tumorHNSC-HPVneg.tumor
⁎⁎⁎
⁎⁎⁎
⁎⁎⁎
⁎⁎⁎
⁎⁎⁎
⁎⁎⁎
⁎⁎⁎
⁎⁎⁎
⁎⁎⁎
⁎⁎⁎
⁎⁎⁎
⁎⁎⁎
⁎⁎
(e)
Figure 8: Continued.
37BioMed Research International
have important roles in determining the prognosis ofHNSCC patients.
The associations among the nine key ceRNA signatures,three immune cell signatures, and different clinicopathologi-cal features was assessed. The results showed that ANLN,KIF23, and ITGA5 expression was significantly correlatedwith grade. Increased KDELC1 and PTX3 expression wasrelated to advanced stage, whereas overexpression of NFIAwas correlated with low tumor stage (Figures 6(a)–6(f)). Arecent study showed that the C1 and C2 subtypes were
enriched in HNSCC and were associated with less favorableoutcomes. The C3 subtype had the most favorable prognosis,whereas the C4 and C6 subtypes had the worst prognoses[53]. In our study, we observed increased expression ofANLN and KIF23 in subtypes C1 and C2, whereas KDELC1showed higher expression in the C1, C2, and C6 subtypes,indicating that it may be associated with worse survival.NFIA showed increased expression in subtype C3 anddecreased expression in C4, which indicated that it couldpredict better survival (Figures 6(g)–6(j)).
(f)
Figure 8: Validation of the prognostic value of identified biomarkers and associations between key ceRNAs and IC genes. (a) Confirmationof prognostic value of key ceRNAs in HNSCC with different HPV statuses via the TIMER 2.0 database. (b–d) Analysis of associationsbetween key immune cells and OS in HNSCC patients with different HPV statuses based on Cox regression analysis using the TIMER2.0 database (http://timer.cistrome.org/). (e) Differences in expression of IC genes with different HPV statuses in HNSCC using TIMER2.0. (f) Exploration of the associations between key ceRNAs and IC molecules with different HPV statuses in HNSCC using TIMER 2.0.
38 BioMed Research International
Recently, Walter et al. [13] reported that the MS subtypewas associated with distant metastases, and that treatmentwith EGFR inhibitors was less likely to be effective in theAT subtype. Our results indicated that CFL2, ITGA5,KDELC1, and PTX3 were highly expressed in the MS sub-type. Higher NFIA expression was associated with the ATsubtype (Figures 6(k)–6(q)). These studies further supportour finding that NFIA expression was correlated with favor-able outcomes whereas higher expression of the other ceR-NAs was associated with unfavorable outcomes.
Previous studies have revealed that naïve B cells andTregs are indicators of better survival, whereas neutrophilshave been associated with HPV positivity and pooreroutcomes [7, 10, 54]. Higher Treg infiltration was found tobe correlated with better prognosis and longer survival inHPV-positive patients compared with HPV-negativeHNSCC patients [55]. By contrast, naïve B cells could becorrelated with tumorigenesis and progression of HNSCC[10]. Neutrophils induce tumor progression and promotetumor cell migration in HNSCC; therefore, neutrophil infil-tration represents a risk factor. [56, 57]. Our integrated anal-yses showed that three immune cell subtypes (naive B cells,Tregs, and neutrophils) could be used as prognosis-relatedbiomarkers in HNSCC. Naïve B cells and Tregs were associ-ated with favorable prognosis, whereas neutrophils repre-sented an unfavorable prognostic marker in HNSCC,especially in HPV-positive HNSCC patients (Figures 4(e)and 8(b)–8(d)). ROC analysis showed that the key immunecell-related model constructed in this study could predictthe prognosis of patients with HNSCC. As shown inFigures 5(j)–5(l), higher levels of naïve B cells and Tregswere related to lower risk scores (P = 0:0085 and P = 4e − 9). These results further suggested that these immune celltypes (naïve B cells, Tregs, and neutrophils) were related toprognosis. Our results are consistent with those of previousstudies, and our immune cell-related model could be usedas an independent factor to assess prognosis in HNSCC.
Finally, we found that eight IC genes exhibited higherexpression in tumor tissues and were correlated with key ceR-
NAs in HNSCC with different HPV statuses (Figures 7(a)and 7(b) and 8(e) and 8(f)). Our identified biomarker couldmore effectively predict anti-PD1 response compared withpublished biomarkers (Figure 7(c)). Previous studies havereported that HPV-positive HNCs expressed high levels ofmultiple T cell exhaustion markers, including LAG3, PD1,TIGIT, and TIM3; the high expression of these markers wascorrelated with improved survival in HPV-positive HNCpatients [58, 59]. Based on these studies and our findings,HNSCC may exhibit strong beneficial responses to immuno-therapy and high expression levels of these key genes maycontribute to predicting improved survival of HNSCCpatients, especially in cases of HPV-positive HNSCC. We alsoobserved that eight key genes were associated with treatmentresponse to most drugs, suggesting the potential of these mol-ecules as therapeutic drug targets in HNSCC (Figure 7(d)).These results provide a scientific rationale for potentiallycombining ICI therapy with inhibitors of the eight key genesidentified in this study to improve treatment efficacy forHNSCC patients.
5. Conclusions
We identified nine key ceRNAs and three immune cell-related signatures as potential biomarkers for predictingthe prognosis of HNSCC. In addition, the KCNQ1OT1(lncRNA), miR-338-3p (miRNA)/miR-29c-3p, ITGA5(mRNA)/KDELC1, and naïve B cell/Treg axes may be linkedto prognosis of HNSCC. As key IC-related members ofceRNAs may be associated with response to ICI therapy,combining ICI with inhibitors of these eight key genesmay contribute to improving treatment efficacy in HNSCpatients. However, additional clinical data and experimentsare required to confirm the prognostic value of thesesignatures and their potential associations with ICI immu-notherapy outcomes in patients with HNSCC. We willperform further experiments to confirm the currentresearch results.
Table 3: Associations between gene expression and therapy outcome in clinical studies of IC blockade.
Gene Cohort Cancer Subtype Survival Risk.adj
ANLNRiaz2017_PD1 Melanoma Ipi_Prog OS 2.025
Riaz2017_PD1 Melanoma Ipi_naive PFS -3.136
CFL2 Liu2019_PD1 Melanoma Ipi_naive OS 2.489
ITGA5Mariathasan2018_PDL1 Bladder mUC OS 3.52
Miao2018_ICB Kidney Clear PFS -3.173
KIF23 Riaz2017_PD1 Melanoma Ipi_Prog OS 2.802
NFIAMariathasan2018_PDL1 Bladder mUC OS 2.987
Zhao2019_PD1 Glioblastoma Pre PFS -2.336
PTX3 Riaz2017_PD1 Melanoma Ipi_naive OS 2.467
RELTMariathasan2018_PDL1 Bladder mUC OS 2.505
Liu2019_PD1 Melanoma Ipi_naive PFS -2.32
TMC7Hugo2016_PD1 Melanoma OS 2.27
Lauss2017_ACT Melanoma OS -2.528
39BioMed Research International
Data Availability
The gene expression RNA-sequencing data and clinicalinformation of HNSCC in the current study were obtainedfrom TCGA data portal (https://portal.gdc.cancer.gov/).
Conflicts of Interest
The authors declare that there is no conflict of interestregarding the publication of this manuscript.
Authors’ Contributions
Ya Guo conceived and designed the article, performed dataanalysis, and wrote the main text of the article. Wei KangPan reviewed the manuscript. Zhong Wei Wang performedlanguage editing. Wang Hui Su and Kun Xu preparedFigures 1–4. Hui Jia and Jing Chen prepared Figures 5–8and tables. Ya Guo and Wei Kang Pan contributed equallyto this work and are co-first authors.
Acknowledgments
This work was supported by the Shaanxi Provincial Natu-ral Science Foundation (grant number 2017JQ8057). Wethank Zhong Guo Liang for bioinformatics-related techni-cal support.
Supplementary Materials
Supplementary 1. Additional file 1. Original source data:online web service.
Supplementary 2. Additional file 2. Original source data:related R software.
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