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Research Article Diagnostic and Prognostic Values of MANF Expression in Hepatocellular Carcinoma Jingyi He, 1 Guangbing Li, 1 Xihan Liu, 2 Liye Ma, 1 Peng Zhang, 1 Jiayao Zhang, 1 Shunzhen Zheng, 1 Jianping Wang, 1 and Jun Liu 1 1 Department of Hepatobiliary Surgery and Center of Organ Transplantation, Shandong Provincial Hospital Aliated to Shandong University, Jinan 250021, Shandong Province, China 2 School of Medicine, Shandong University, Jinan 250021, Shandong Province, China Correspondence should be addressed to Jun Liu; [email protected] Received 29 October 2019; Revised 15 March 2020; Accepted 24 March 2020; Published 22 April 2020 Academic Editor: Naohiko Masaki Copyright © 2020 Jingyi He et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Hepatocellular carcinoma (HCC) is one of the most common malignant tumors, and its prognosis is still poor. Mesencephalic astrocyte-derived neurotrophic factor (MANF) plays a key role in endoplasmic reticulum stress. ER stress plays a key role in HCC carcinogenesis. To conrm the clinical and prognostic value of MANF in HCC, we investigated the expression level of MANF in HCC as recorded in databases, and the results were veried by experiment. Survival analysis was probed by the KaplanMeier method. Cox regression models were used to ascertain the prognostic value of MANF in HCC tissue microarray. The diagnostic value of MANF in HCC was evaluated by receiver operating characteristic curve analysis. Potential correlation between MANF and selected genes was also analyzed. Results showed that MANF was overexpressed in HCC. Patients with high MANF expression levels had a worse prognosis and higher risk of tumor recurrence. Furthermore, the expression level of MANF had good diagnostic power. Correlation analysis revealed potential regulatory networks of MANF in HCC, laying a foundation for further study of the role of MANF in tumorigenesis. In conclusion, MANF was overexpressed in HCC and related to the occurrence and development of HCC. It is a potential diagnostic and prognostic indicator of HCC. 1. Introduction Liver cancer is one of the most common human malignant gastrointestinal tumors and the fourth leading cause of cancer-related deaths worldwide [1, 2]. Hepatocellular carci- noma (HCC) characterized by its asymptomatic nature, high malignancy, early metastasis, and poor curative ecacy is responsible for >90% of primary liver cancers [35]. Despite recent therapeutic approaches such as surgical resection, radiofrequency ablation, and orthotropic liver transplanta- tion, the prognosis of HCC remains poor. The metastasis and recurrence of HCC signicantly reduce the survival rate and quality of life of HCC patients [58]. Therefore, novel biomarkers will be substantially benecial for HCC diagnosis and treatment, and outcomes of HCC patients urgently need to be improved. Mesencephalic astrocyte-derived neurotrophic factor (MANF), also named arginine-rich mutated in early tumors (ARMET), was rst discovered as a new dopaminergic neu- rotrophic factor in astrocyte-conditioned medium by Petrova et al. in 2003 [9]. Apart from being secreted into the extra- cellular space, MANF has been found to remain inside the cells and localize in the endoplasmic reticulum (ER) lumen [10, 11]. Induction of ER stress in vitro causes upregulation of endogenous MANF expression [12, 13]. Hakonen et al. have shown that the protective eect of MANF is associated with inhibition of the nuclear factor- (NF-) κB signaling pathway and alleviation of ER stress. MANF also enhances human beta cell proliferation when transforming growth factor- (TGF-) β signaling is inhibited [14]. In recent studies, ER stress has been shown to mediate HCC promoted by nonalcoholic fatty liver disease, and the NF-κB pathway is Hindawi BioMed Research International Volume 2020, Article ID 1936385, 18 pages https://doi.org/10.1155/2020/1936385

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Page 1: Diagnostic and Prognostic Values of MANF Expression in ... · GTAG-3′, reverse—5′-GGAAAGCTCCAGGCTTCACA-3′. The primers of β-actin were as follows: forward—5′-GAAGAGCTACGAGCTGCCTGA-3′,reverse—5′-CAGA

Research ArticleDiagnostic and Prognostic Values of MANF Expression inHepatocellular Carcinoma

Jingyi He,1 Guangbing Li,1 Xihan Liu,2 Liye Ma,1 Peng Zhang,1 Jiayao Zhang,1

Shunzhen Zheng,1 Jianping Wang,1 and Jun Liu 1

1Department of Hepatobiliary Surgery and Center of Organ Transplantation, Shandong Provincial Hospital Affiliated toShandong University, Jinan 250021, Shandong Province, China2School of Medicine, Shandong University, Jinan 250021, Shandong Province, China

Correspondence should be addressed to Jun Liu; [email protected]

Received 29 October 2019; Revised 15 March 2020; Accepted 24 March 2020; Published 22 April 2020

Academic Editor: Naohiko Masaki

Copyright © 2020 Jingyi He 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.

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors, and its prognosis is still poor. Mesencephalicastrocyte-derived neurotrophic factor (MANF) plays a key role in endoplasmic reticulum stress. ER stress plays a key role inHCC carcinogenesis. To confirm the clinical and prognostic value of MANF in HCC, we investigated the expression level ofMANF in HCC as recorded in databases, and the results were verified by experiment. Survival analysis was probed by theKaplan–Meier method. Cox regression models were used to ascertain the prognostic value of MANF in HCC tissue microarray.The diagnostic value of MANF in HCC was evaluated by receiver operating characteristic curve analysis. Potential correlationbetween MANF and selected genes was also analyzed. Results showed that MANF was overexpressed in HCC. Patients withhigh MANF expression levels had a worse prognosis and higher risk of tumor recurrence. Furthermore, the expression level ofMANF had good diagnostic power. Correlation analysis revealed potential regulatory networks of MANF in HCC, laying afoundation for further study of the role of MANF in tumorigenesis. In conclusion, MANF was overexpressed in HCC andrelated to the occurrence and development of HCC. It is a potential diagnostic and prognostic indicator of HCC.

1. Introduction

Liver cancer is one of the most common human malignantgastrointestinal tumors and the fourth leading cause ofcancer-related deaths worldwide [1, 2]. Hepatocellular carci-noma (HCC) characterized by its asymptomatic nature, highmalignancy, early metastasis, and poor curative efficacy isresponsible for >90% of primary liver cancers [3–5]. Despiterecent therapeutic approaches such as surgical resection,radiofrequency ablation, and orthotropic liver transplanta-tion, the prognosis of HCC remains poor. The metastasisand recurrence of HCC significantly reduce the survival rateand quality of life of HCC patients [5–8]. Therefore, novelbiomarkers will be substantially beneficial for HCC diagnosisand treatment, and outcomes of HCC patients urgently needto be improved.

Mesencephalic astrocyte-derived neurotrophic factor(MANF), also named arginine-rich mutated in early tumors(ARMET), was first discovered as a new dopaminergic neu-rotrophic factor in astrocyte-conditioned medium by Petrovaet al. in 2003 [9]. Apart from being secreted into the extra-cellular space, MANF has been found to remain inside thecells and localize in the endoplasmic reticulum (ER) lumen[10, 11]. Induction of ER stress in vitro causes upregulationof endogenous MANF expression [12, 13]. Hakonen et al.have shown that the protective effect of MANF is associatedwith inhibition of the nuclear factor- (NF-) κB signalingpathway and alleviation of ER stress. MANF also enhanceshuman beta cell proliferation when transforming growthfactor- (TGF-) β signaling is inhibited [14]. In recent studies,ER stress has been shown to mediate HCC promoted bynonalcoholic fatty liver disease, and the NF-κB pathway is

HindawiBioMed Research InternationalVolume 2020, Article ID 1936385, 18 pageshttps://doi.org/10.1155/2020/1936385

Page 2: Diagnostic and Prognostic Values of MANF Expression in ... · GTAG-3′, reverse—5′-GGAAAGCTCCAGGCTTCACA-3′. The primers of β-actin were as follows: forward—5′-GAAGAGCTACGAGCTGCCTGA-3′,reverse—5′-CAGA

closely associated with initiation of cancer [15, 16]. So thediagnostic value and clinical significance of MANF in HCCremain to be elucidated.

In this study, we investigated MANF expression in HCCcell lines, HCC tissues, and nontumor tissues by analyzingthe data from bioinformation databases and confirmed ourfindings by Western blotting, polymerase chain reaction(PCR), and immunohistochemical staining. We examinedthe clinical and prognostic value of MANF in HCC patients.

2. Material and Methods

2.1. Ethics Statement. This study was approved by the Aca-demic Committee of Shandong Provincial Hospital Affiliatedto Shandong University and conducted according to theprinciples expressed in the Declaration of Helsinki. All thedatasets were retrieved from the publishing literature, andall written informed consent was obtained. This article doesnot contain any studies with animals performed by any ofthe authors.

2.2. Patients and Specimens. A total of 311 patients undergo-ing hepatectomy between January 2011 and December 2014were included in the study. HCC samples and paratumor tis-sues including 45 freshly frozen HCC samples, and 266 tissuemicroarrays (TMAs) were collected. We summarized theircharacteristics and study cohort diagram in Table S2. Noneof the patients had received chemotherapy or radiotherapybefore we obtained the tissue specimens. The clinicalstaging was based on the 7th edition of the American JointCommittee on Cancer (AJCC) Staging System.

2.3. Real-Time PCR. Total RNA from liver tissues was iso-lated by the TRIzol reagent (Invitrogen, Life Technologies,Carlsbad, CA, USA), and 1μg mRNAwas reverse transcribedto cDNA using the PrimeScript RT Reagent Kit Perfect RealTime (Takara Bio, Japan) according to the manufacturer’sinstructions. Reverse transcription- (RT-) PCR was con-ducted using the LightCycler 480 II Real-Time PCR System(Roche, Switzerland) with SYBR Green PCR Master Mix(Toyobo, Osaka, Japan). An initial denaturation at 95°C for10min was followed with PCR cycling: 94°C (30 s), 60°C

(30 s), and 72°C (60 s) for 40 cycles. The primers of MANFwere as follows: forward—5′-GTGCACGGACCGATTTGTAG-3′, reverse—5′-GGAAAGCTCCAGGCTTCACA-3′. The primers of β-actin were as follows: forward—5′-GAAGAGCTACGAGCTGCCTGA-3′, reverse—5′-CAGACAGCACTGTGTTGGCG-3′. Products were analyzed bymelt curve analysis and agarose gel electrophoresis to deter-mine product size and to confirm that no byproducts wereformed. Results were expressed relative to the number ofβ-actin transcripts used as an internal control.

2.4. Western Blot Analysis. Liquid nitrogen frozen liver tis-sues were immersed in RIPA-added phenylmethylsulfonylfluoride (100 : 1) (Beyotime, China) supplemented withprotease and phosphatase inhibitors and sonicated on iceto obtain a homogenate. Specimens were centrifuged at15 000 × g for 15min, and the supernatant was used forWestern blotting and ELISA. Concentration of the proteinwas assessed by BCA protein assay kit (Beyotime). Proteinswere separated on SDS-PAGE and transferred to nitro-cellulose membranes. After incubation with horseradishperoxidase-conjugated secondary antibodies for 2 h at roomtemperature, signals were detected by chemiluminescentreagents (Millipore, USA) and β-actin served as an internalcontrol. The primary antibodies were as follows: rabbitanti-ARMET (Abcam, Cambridge, MA, USA; diluted1 : 1000) and rabbit anti-β-actin (Cell Signaling Technology,Danvers, MA, USA; diluted 1 : 1000). Immunoreactivitywas detected using the FluorChem ChemiluminescentWestern Blot Imaging System (Cell Biosciences, Santa Clara,CA, USA).

2.5. Immunohistochemical (IHC) Detection of TissueMicroarray (TMA). Two hundred and sixty-six HCCpatients, including 259 who had follow-up information, wereanalyzed. For immunohistochemistry, 5μm tissue sectionswere prepared from each block. Tissue sections were deparaf-finized, rehydrated, and rinsed in distilled water. After heat-ing the sections in 10mmol/L citrate buffer for antigenretrieval, the sections were incubated with primary antibodyagainst ARMET (Abcam; dilution at 1 : 100) at 4°C, followedby secondary antibody for 1 h at room temperature. An

Table 1: The significant changes of MANF expression in transcription level of HCC vs. normal tissues (ONCOMINE database).

Tissue types Fold change P value t-test References Overexpression gene rank

HCC vs. normal 1.945 1.54E-53∗∗ 1.77E+01Roessler Liver 2 Statistics(Roessler et al., Cancer Res

2010/12/15)

386 of 12,624 measured genes(in top 4%)

HCC vs. normal 1.398 0.0000514∗∗ 3.984Chen Liver Statistics (Chen et al.,

Cancer Res 2010/12/15)1850 of 10,802 measured genes

(in top 18%)

HCC vs. normal 1.435 0.011∗ 2.391Roessler Liver Statistics (Roessleret al., Cancer Res 2010/12/15)

3333 of 12603 measured genes(in top 27%)

HCC vs. normal 1.482 0.122 1.236Wurmbach Liver Statistics

(Wurmbach et al., Hepatology2007/04/01)

7466 of 19,574 measured genes(in top 39%)

HCC vs. normal -2.279 1 -6.273Mas Liver Statistics (Mas et al.,

Mol Med 2008/12/21)12189 of 12,603 measured

genes (in top 97%)

Notes: ∗P < 0:05; ∗∗P < 0:01.

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Analysis type by cancer

Cancervs.

normal

Bladder cancer

Sarcoma cancerProstate cancer

Pancreatic cancerOvarian cancer

Other cancerMyeloma

MelanomaLymphoma

Lung cancerLiver cancer

LeukemiaKidney cancer

Head and Neck cancerGastric cancer

Esophageal cancerColorectal cancer

Cervical cancerBreast cancer

Brain and CNS cancer1

354310

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1

1

111

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5 11 10 510

%

(a)

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LIHC(num(T) = 369; num(N) = 50)

(b)

The gene expression profile across all tumor samples and paired normal tissues.(Bar plot)

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Figure 1: Continued.

3BioMed Research International

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intensity score of 0–3 was assigned for the intensity of tumorsamples (0, none; 1, weak; 2, intermediate; and 3, strong) andthe percentage of stained cells, assigning a score of 0–300. Toassess the average degree of staining within a sample, multipleregions were analyzed. AnH score was calculated using the fol-lowing formula: H = ðpercentage of cells of weak intensity × 1Þ+ ðpercentage of cells of moderate intensity × 2Þ + ðpercentageof cells of strong intensity × 3Þ. The scoring was independentlyassessed by two assessors who were not aware of the clinicaloutcomes.

2.6. GEO Data Source. Meta-analysis of 24 sets of microar-rays from the GEO database (http://www.ncbi.nlm.nih.gov/geo/) including 1475 HCC specimens and 981 nontumorspecimens was used to evaluate the diagnostic power ofMANF. The 24 cohorts consisted of GSE17548, GSE20140,GSE29722, GSE31370, GSE36411, GSE39791, GSE41804,GSE45050, GSE45267, GSE47595, GSE57958, GSE62232,GSE63898, GSE64041, GSE75285, GSE76311, GSE76427,GSE84006, GSE84402, GSE84598, GSE98383, GSE102083,GSE112791, and GSE121248 datasets. We summarized theircharacteristics such as cohort ID, RNA-seq platform, samples

size (nontumor and tumor samples), publication year, andcountry in Table S1.

2.7. Statistics for Meta-analysis. Stata 12.0 was utilized to ana-lyze the pooled diagnostic value of MANF with the data fromthe GEO dataset. I2 was used to evaluate the heterogeneity ofthose studies, which indicated significant heterogeneity atI2 > 50%. The random effects model was used, and sub-group analysis was performed to explore the source of hetero-geneity, while heterogeneity was conspicuous between thosestudies. Publication bias was determined by Begg’ s funnelplot and Egger’s test.

2.8. ONCOMINE Analysis. ONCOMINE (http://www.oncomine.org/), an online cancer microarray database, wasused to analyze differential expression classification in differ-ent cancers with their respective normal tissues and theirclinical and pathological characteristics. MANF expressionin HCC samples was compared with that in nontumor sam-ples. The P value was generated utilizing Students’ t-test. Thecut-off P value and fold change were defined as 0.01 and 2,respectively.

0

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9)

(d)

Figure 1: MANF expression levels in different types of human tumors. (a) Increased or decreased MANF in datasets of different tumorscompared with normal tissues in the ONCOMINE database. Cell color is determined by the best gene rank percentile for the analyseswithin the cell. An analysis may be counted in more than one cancer type. (b) GEPIA generates box plots for comparing MANFexpression in HCC (n = 369) and normal (n = 50) tissues (∗P < 0:01) (c) Bar plot of MANF expression profile across all tumor samplesand paired normal tissues. (d) Human MANF expression levels in different tumor types from the TCGA database were analyzed byGEPIA. Bar height represents the median expression of certain tumor type or normal tissue.

4 BioMed Research International

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2.9. GEPIA Dataset. The online database Gene ExpressionProfiling Interactive Analysis (GEPIA), providing customiz-able functions, is a newly developed interactive web serverfor analyzing the RNA sequencing expression data and prog-nostic value. Tumors and nontumor specimens in the GEPIAdatabase were derived from The Genotype-Tissue Expression(GTEx) and The Cancer Genome Atlas (TCGA) projects(http://gepia.cancerpku.cn/index.html) [17]. Tumor/nontu-mor differential expression analysis, patient survival analysis,and correlation analysis were explored using the GEPIAdatabase. We selected the median as the group cut-off forsurvival plots.

2.10. CCLE Dataset. Cancer Cell Line Encyclopedia (CCLE)project is a collaboration concentrated on a detailed geneticand pharmacological characterization of a large panel ofhuman cancer cell lines, in order to develop integratedcomputational analyses that link distinct pharmacologicalvulnerabilities to genomic patterns and to translate cell lineintegrative genomics into clinical application. Genomic data,analysis, and visualization providing by CCLE for around1000 cell lines are available for public access [18]. CCLE gene

expression data of MANF were downloaded and collectedfrom https://portals.broadinstitute.org/ccle/data.

2.11. LinkedOmics Dataset. LinkedOmics is a user-friendlybioinformatics web in the software ecosystem for disseminat-ing data from large-scale cancer omics projects. It uses pre-processed and normalized data from the Broad TCGAFirehose and CPTAC data portal to reduce redundant effortsand focuses on exploration and interpretation of attributeassociations and thus complements existing cancer data por-tals [19]. Correlation analysis data were collected and down-loaded from http://www.linkedomics.org/admin.php.

2.12. EMBL-EBI Dataset. EMBL-EBI (https://www.ebi.ac.uk)is a user-friendly bioinformatics web and programmatic toolframework providing free and open access to a range of bio-informatics applications for sequence analysis [20]. Theexpression data of MANF in HCC cell lines was collectedfrom the EMBL-EBI dataset.

2.13. Data Analysis and Statistics. SPSS version 22.0 (IBMCorporation, Armonk, NY, USA) and GraphPad Prism ver-sion 6.0 (GraphPad Software, La Jolla, CA, USA) were used

Expression level in TPM0 2027

HLF Hep 382.1-7 HuH-7 JHH-2 JHH-4 JHH-6JHH-5 JHH-7 Li-7 PLC/PRF/5

SK-HEP-1 SNU-182 SNU-387 SNU-398 SNU-423 SNU-449 SNU-475 SNU-761 SNU-878 SNU-886 huH-1

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(b)

Figure 2: MANF expression levels in different types of cell lines. (a) Expression of MANF translational in HCC cell lines was tested byEMBL-EBI bioinformatics website. The darker the blue, the higher the level of MANF expression. (b) Expression of MANF in the celllines was analyzed via CCLE databases. Liver cell lines are indicated by the red arrow.

5BioMed Research International

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Note: weights are from random effects analysisOverall (I-squared = 0.0%, P = 0.489)

GSE112791 (2019)

GSE29722 (2011)GSE20140 (2011)

GSE45267 (2014)

GSE102083 (2018)

GSE76311 (2017)

GSE62232 (2014)

GSE84006 (2017)GSE84402 (2017)

GSE39791 (2012)

GSE75285 (2016)

GSE57958 (2014)

GSE31370 (2012)

GSE64041 (2014)

GSE121248 (2018)

GSE47595 (2014)

GSE76427 (2017)

GSE41804 (2013)

GSE84598 (2017)

GSE36411 (2015)

GSE45050 (2017)

GSE98383 (2018)

GSE17548 (2013)

Study ID

GSE63898 (2015)

5.28 (4.37, 6.39)

7.33 (1.61, 33.41)

5.44 (0.80, 36.87)8.02 (2.74, 23.51)

5.52 (2.20, 13.87)

6.93 (3.94, 12.19)

6.24 (2.82, 13.83)

27.51 (1.56, 485.37)

10.38 (3.61, 29.90)3.24 (0.69, 15.20)

7.78 (3.71, 16.33)

4.70 (0.49, 45.03)

20.90 (6.57, 66.43)

6.00 (0.53, 67.65)

3.65 (1.74, 7.65)

5.60 (2.29, 13.72)

2.51 (1.21, 5.20)

5.58 (2.64, 11.79)

5.44 (1.41, 21.05)

7.11 (1.89, 26.80)

6.25 (2.42, 16.11)

15.00 (1.03, 218.30)

1.98 (0.53, 7.34)

2.75 (0.72, 10.48)

OR (95% CI)

3.90 (2.55, 5.95)

100.00

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6.83

6.47

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Weight%

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1.00206 485

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Begg’s funnel plot with pseudo 95% confidence limits

Logo

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Figure 3: Continued.

6 BioMed Research International

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for statistical analyses. We select the median expression levelfor splitting the high-expression and low-expression cohorts.Samples with expression level higher than this threshold areconsidered the high-expression cohort. Samples with expres-sion level lower than this threshold are considered the low-expression cohort. The χ2 test was used to explore thecorrelation between MANF expression levels and the clinico-pathological parameters. Survival analysis was performed bythe Kaplan–Meier method. The relationship between differ-ent variables and survival was determined by the multivariateCox proportional hazards method. The pooled diagnosticvalue of MANF in HCC was analyzed via receiver-operating characteristic (ROC) curves. The linear associationbetween two variables was evaluated by Pearson’s correla-tion. All of the data of samples are presented as the mean ±standard deviation (SD). The differences between tumorand nontumor samples were determined with nonparametrictests. In all cases, P < 0:05 was considered to be statisticallysignificant.

3. Results

3.1. MANF Overexpression in HCC Was Explored byAnalyzing Bioinformation Databases. We analyzed MANFmRNA expression in HCC tissues and paired nontumor tis-sues using the ONCOMINE and GEPIA databases. Com-pared to nontumor samples, ONCOMINE demonstratedthat MANF was significantly upregulated in HCC samples(P < 0:01), while the other two statistics had no significancein this regard (Table 1). We compared transcriptional levelsof MANF in cancer with those in normal tissues usingONCOMINE (Figure 1(a)). GEPIA showed that mRNA of

MANF was significantly overexpressed in HCC samplesand many other types of cancer (Figures 1(b)–1(d)).

We used the EMBL-EBI bioinformatics website to mea-sure the expression of MANF in HCC cell lines, which indi-cated that MANF was upregulated in 21 HCC cell lines(Figure 2(a)). The CCLE database showed that MANF washighly expressed in a variety of cell lines originated fromdifferent tissue types (Figure 2(b)).

To explore further whether MANF expression was higherin HCC tissues than in nontumor tissues, 24 HCC microar-rays from the GEO database were subjected to meta-analysis. Like the forest plot in Figure 3(a), higher MANFexpression was found in HCC tissues than in the nontumortissue [pooled odds ratio ðORÞ = 5:28, 95% confidence inter-val ðCIÞ = 4:367–6.388, I2 = 0%, P = 0:489]. All the data weregenerated by a random effects model, and the χ2 test wasused to analyze study heterogeneity. Publication bias wasassessed with Begg’s test, Egger’s test, and funnel plots(Figures 3(b)–3(d)). There were no significant publicationbias and heterogeneity. As shown in the sensitivity analysis,there were no significant differences between these microar-rays (Figure 3(e)). Hence, high expression of MANF inHCC samples was identified by meta-analysis.

3.2. MANF Upregulated in HCC Was Confirmed byExperiments. To confirm the expression level of MANF, weexamined mRNA and protein levels of MANF in HCC andpaired nontumor samples, utilizing quantitative RT-PCRand Western blotting. MANF expression in HCC tissues(n = 45) was higher than that in nontumor tissues (n = 45)(PCR, P < 0:05; Western blotting, P < 0:01) (Figures 4(a)–4(c)). We characterized MANF protein expression in humanHCC and nontumor specimens by TMA. We analyzed

4.17 5.284.37 6.39 7.05

GSE17548 (2013)

Lower CI limit Estimate Upper CI limit

Meta-analysis estimates, given named study is omitted

GSE20140 (2011) GSE29722 (2011) GSE31370 (2012) GSE36411 (2015) GSE39791 (2012) GSE41804 (2013) GSE45050 (2017) GSE45267 (2014) GSE47595 (2014) GSE57958 (2014) GSE62232 (2014) GSE63898 (2015) GSE64041 (2014) GSE75285 (2016) GSE76311 (2017) GSE76427 (2017) GSE84006 (2017) GSE84402 (2017) GSE84598 (2017) GSE98383 (2018)

GSE102083 (2018)GSE112791 (2019)GSE121248 (2018)

(e)

Figure 3: Meta-analysis for evaluating expression level of MANF in HCC. Each point represents a single microarray study. (a) Forest plotevaluating differences in MANF expression between HCC and nontumor tissues. Low and high MANF-expressing samples were regardedas the control and experimental groups, respectively. (b) Begg’s test for the publication bias test of GEO databases. (c) Egger’s test for thepublication bias test of GEO databases. (d) Funnel plot for the publication bias test of GEO databases. (e) Sensitivity analysis wascalculated by omitting each microarray in turn.

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MANF protein expression by immunohistochemical stainingof HCC and paired nontumor tissues and found that MANFwas significantly upregulated in HCC tissues compared withadjacent nontumor tissues (n = 266) (P < 0:01) (Figures 4(d)and 4(e)).

3.3. Diagnostic Value of MANF. The diagnostic value ofMANF in identifying HCC and nontumor samples was eval-

uating by ROC curve analysis. Areas under the curve (AUCs)from GEO databases were as follows: GSE39791, 0.811 (95%CI: 0.740–0.882, P < 0:0001; Figure 5(a)) with cut-off point,and respective specificities and sensitivities were 10.075,0.722, and 0.806; GSE63898, 0.677 (95% CI: 0.625–0.730,P < 0:0001; Figure 5(b)) with cut-off point, and respectivespecificities and sensitivities were 10.4102, 0.544, and0.821; GSE64041, 0.710 (95% CI: 0.619–0.801, P < 0:0001;

2.0

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N1 T1 N2 T2 N3 T3 N4 T4 N5 T5 N6 T6

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200um

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250

0Nontumor Tumor

MA

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Figure 4: MANF expression levels in HCC compared with nontumor tissues. (a, b) MANF mRNA (∗∗∗P < 0:001) and protein (∗P < 0:05)expression levels in HCC clinical specimens compared with paired nontumor specimens were shown by box plots. (c) RepresentativeWestern blotting of HCC clinical specimens compared with paired nontumor specimens. N: normal tissue; T: tumor tissue.(d) Immunohistochemical analysis of MANF in HCC tissues and adjacent nontumor tissues previously analyzed by TMA (∗∗∗P < 0:001).(e) Representative MANF staining in HCC and normal tissues.

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ROC curve (GSE39791)1.0

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Figure 5: Continued.

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Figure 5(c)) with cut-off point, and respective specificitiesand sensitivities were 9.1892, 0.631, and 0.750; GSE76427,0.749 (95% CI: 0.668–0.830, P < 0:0001; Figure 5(d)) withcut-off point, and respective specificities and sensitivitieswere 3357.82, 0.722, and 0.750; GSE102083, 0.782 (95%CI: 0.727–0.838, P < 0:0001; Figure 5(e)) with cut-off point,and respective specificities and sensitivities were 9.542,0.618, and 0.848. AUCs from immunohistochemistry ofTMA were 0.570 (95% CI: 0.522–0.619, P < 0:01;Figure 5(f)) with cut-off point, and respective specificitiesand sensitivities were 152.7620, 0.643, and 0.5. Resultsindicate thatMANFwas a reliable diagnostic marker in HCC.

To analyze expression levels of MANF in dysplastic nod-ules, the GEO database was searched. GSE98620 was the onlydatabase that meets the retrieval requirements. The resultshowed that higher MANF expression was found in HCC tis-sues than in dysplastic nodules (P < 0:001) (Figure 5(g)), andthere was no statistical difference between normal tissues anddysplastic nodules.

Correlation analysis of MANF expression and TNMstaging was performed using LinkFinder of LinkedOmics.There was no significant correlation between highMANF expression and TNM pathological stage (P > 0:05)(Figures 5(h)–5(k)).

Expr

essio

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lue

of G

SE98

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mal

(n =

6)

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tic(n

= 2

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(n =

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MA

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MA

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MANF vs. pathology M stage(n = 263)

MA

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10

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(k)

Figure 5: Diagnostic value of MANF in HCC was evaluated by ROC curve analysis among GEO databases. The blue line indicates HCCtissues while the green one indicates nontumor tissues. (a) ROC curve analysis of GSE39791 from GEO databases. (b) ROC curve analysisof GSE63898 from GEO databases. (c) ROC curve analysis of GSE64041 from GEO databases. (d) ROC curve analysis of GSE76427 fromGEO databases. (e) ROC curve analysis of GSE102083 from GEO databases. (f) ROC curve analysis of TMA. (g) MANF expression valueof different types of tissues in GSE98620 database (∗∗∗P < 0:001). (h–k) Correlation analysis of MANF expression and TNM stagingobtained in LinkFinder of LinkedOmics.

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3.4. Prognostic Value of MANF. To investigate further theprognostic role of MANF in HCC patients, GEPIA databaseand supporting clinical data of TMA were analyzed. We ana-

lyzed TCGA prognostic data and MANF transcriptional levelof HCC (n = 364) using the GEPIA database. The overall sur-vival rates of HCC patients with high expression of MANF

Overall survival

Months

Perc

ent s

urvi

val

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0 20 40 60 80 100 120

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.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00Months

<Median≥Median

<Median censored≥Median censored

(d)

Figure 6: Correlation between MANF expression and clinical or prognostic parameters. (a, b) Association between MANF expression andoverall survival and disease-free survival in HCC patients, from the GEPIA database. The log-rank test (Mantel–Cox test) was used toanalyze the relationship between overall survival (P < 0:05), disease-free survival (P > 0:05), and MANF expression in patients with HCC.(c, d) Association between MANF expression and overall survival and disease-free survival in HCC patients from TMA analysis. TheKaplan–Meier test was used to analyze the relationship between overall survival (P > 0:05), disease-free survival (P < 0:05), and MANFexpression in patients with HCC.

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were significantly lower (P < 0:05) (Figure 6(a)) than those ofpatients with low expression of MANF. Disease-free survivaldid not differ significantly (Figure 6(b)). Beyond that, theTMA analysis of 259 HCC patients showed that patients withhigh MANF expression had shorter disease-free survival(P < 0:05) (Figure 6(d)) compared with patients with lowexpression of MANF. No significant difference was foundin overall survival (Figure 6(c)). Therefore, high expressionof MANF is a prognostic factor for HCC.

Patients with high MANF expression levels had a signif-icantly higher risk of tumor recurrence (P < 0:05) (Table 2).There was no correlation of MANF expression with age,sex, α-fetoprotein (AFP) levels, hepatitis B virus infection,cirrhosis, tumor size, tumor number, TNM stage, differentia-

tion grade, and venous invasion. Univariate Cox regressionanalysis showed that tumor number (P < 0:01), AFP level(P < 0:05), TNM stage (P < 0:05), and venous invasion(P < 0:001) were independent prognostic factors for HCCpatients. Multivariate Cox regression analysis showed thatonly venous invasion (P < 0:001) was an independent prog-nostic factor for HCC (Table 3).

3.5. Coexpression Genes Correlated with MANF in HCC.MANF association results were confirmed using LinkFinderof LinkedOmics to analyze mRNA sequencing data from367 HCC patients in the TCGA via Pearson’s correlation test.The volcano plot (Figure 7(a)) shows that there were 3773genes positively correlated with MANF (marked by red dots)

Table 2: The relationship between MANF status and clinicopathological features of HCC (tissue microarray).

Clinicopathological features Number of cases (n)MANF expression, n (%)

P valueHigh Low

Age

≥Median 133 64 (48.1) 69 (51.9) 0.54

<Median 133 69 (51.9) 64 (48.1)

Gender

Male 241 123 (51) 118 (49) 0.293

Female 25 10 (40) 15 (60)

HBV

Positive 245 124 (50.6) 121 (49.4) 0.495

Negative 21 9 (42.9) 12 (57.1)

Cirrhosis

Positive 220 108 (49.1) 112 (50.9) 0.517

Negative 46 25 (54.3) 21 (45.7)

Tumor size

≥5 221 106 (48) 115 (52) 0.141

<5 45 27 (60) 18 (40)

Tumor number

Single 153 73 (47.7) 80 (52.3) 0.385

Multiple 113 60 (53.1) 53 (46.9)

AFP

≥20 201 95 (47.3) 106 (52.7) 0.117

<20 65 38 (58.5) 27 (41.5)

TNM stage

Stage I-II 124 68 (54.8) 56 (45.2) 0.104

Stage III-IV 142 65 (45.8) 77 (54.2)

Differentiation grade

Grade 1-2 182 94 (51.6) 88 (48.4) 0.429

Grade 3-4 84 39 (46.4) 45 (53.6)

Vasoinvasion

Yes 53 28 (52.8) 25 (47.2) 0.645

No 213 105 (49.3) 108 (50.7)

Tumor recurrence

Yes 110 64 (58.2) 46 (41.8) 0.025 ∗

No 156 69 (44.2) 87 (55.8)

Notes: ∗P < 0:05; ∗∗P < 0:01.

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and 4404 genes negatively correlated (marked by green dots)(P < 0:01, FDR < 0:01). The top 50 significant gene sets pos-itively and negatively correlated with MANF are shown inthe heat map (Figures 7(b) and 7(c)). As it turns out, MANFhas extensive influence on the transcriptome.

We examined the correlations between MANF and thetop 10 genes with the highest expression multiples in HCC.

MANF was significantly correlated with UBD, MDK, andAKR1B10 and had some degree of correlation with othergenes (Figures 8(a)–8(c)).

To confirm the role of MANF expression in the develop-ment of cancer, we used LinkFinder or LinkedOmics to ana-lyze the relationship with common oncogenes and tumorsuppressor genes. There were negative correlations between

Table 3: Univariate and multivariate analyses of prognostic variables for overall survival in HCC patients.

Clinicopathological featuresUnivariate analysis Multivariate analysis

HR 95% (CI) P value HR 95% (CI) P value

MANF expression (T)

Low 1.000

High 1.070 0.829-1.380 0.605

MANF expression (NT)

Low 1.000

High 0.896 0.694-1.158 0.401

Age

<Median 1.000

≥Median 1.014 0.786-1.307 0.917

Gender

Male 1.000

Female 0.751 0.470-1.202 0.233

HBV

Negative 1.000

Positive 1.169 0.731-1.870 0.514

Cirrhosis

Negative 1.000

Positive 0.931 0.664-1.304 0.677

Tumor size

<5 1.000

≥5 1.218 0.869-1.705 0.252

Tumor number

Single 1.000 1.000

Multiple 1.442 1.114-1.867 0.005∗∗ 1.278 0.955-1.710 0.099

AFP

<20 1.000 1.000

≥20 1.360 1.013-1.827 0.041∗ 1.142 0.838-1.555 0.401

TNM stage

Stage I-II 1.000 1.000

Stage III-IV 1.404 1.086-1.814 0.010∗ 0.991 0.726-1.353 0.957

Differentiation grade

Grade 1-2 1.000

Grade 3-4 0.955 0.725-1.260 0.746

Vasoinvasion

No 1.000 1.000

Yes 2.757 1.993-3.813 <0.001∗∗ 2.521 1.769-3.591 <0.001∗∗

Tumor recurrence

No 1.000

Yes 0.815 0.630-1.054 0.119

Notes: ∗P < 0:05; ∗∗P < 0:01. T: tumor tissue; NT: nontumor tissue.

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MANF expression and RB1 (Pearson’s correlation = ‐0:3048,P < 0:01) and BRCA2 (Pearson’s correlation = ‐0:3493,P < 0:01) (Figures 8(d) and 8(e)).

4. Discussion

HCC accounts for >90% of the histological types of primarymalignant liver tumors, which are highly malignant and havea high recurrence rate and poor prognosis [3, 4]. Therefore,

elucidating the molecular mechanisms underlying the pro-gression and initiation of HCC is important for treatmentselection.

ER stress can be induced by oncogene activation, such asB-Raf proto-oncogene mutations, H-Ras proto-oncogenemutations, and c-Myc amplification, as well as chemothera-peutic drugs [21]. When the ER functions, only correctlyfolded proteins can reach their cell compartment andunfolded or misfolded proteins accumulate within the ER

–Lo

g10

(P v

alue

)

Pearson correlation coefficient (Pearson test)–1.5 –1.0 –0.5 0.0 0.5 1.0 1.5 2.0

60

50

40

30

20

10

0

MANF Association Result

>310–1<–3

420–2–4

Z-score group

(a)

MANFCALRSDF2L1PPIBCRELD2DNAJB11PDIA3HSP90B1HSPA5C19orf10TMED9GMPPAHM13CDK2AP2C6orf126CYB561D2SEC61GSLC35B1FKBP2PGPSRPRBRPN1ATP6V0BSELKATP6V1C2COPEBRMS1C11orf51GMPPBC11orf48SSR2STX5B2GAR3MRPL52C8orf76NAA10SRMNUDCPDIA6CFL1ZBTB8OSTXNL4APSMD13SSR4NANSPSMB3DYNLL1SPR19DUSP23DAD1

(b)

CLASP1ALS2CR8C5orf41RREB1TATD2CDK13SECISBP2LPARD3BSHPRHDAAM1PTAR1REV3LKLHL11MLL5KIF27ATF7ANKRD26SPATA13ZNF791ROCK2PHF2BOD1LSEPT10HEATR5BZNF192ATXN1LARHGAP32EPB41L5BBS10MARCH8BBS1NEU3ZNF236RESTKIAA1267RABGAP1GPATCH8JMJD1CPPTC7MORC3DLG1LRRC58C9orf102HIPK3FAM179BRASA2EP300KRIT1RNF111KCTD18

(c)

Figure 7: Genes differentially expressed in correlation with MANF in HCC (LinkedOmics). (a) Correlations between MANF and genesdifferentially expressed in HCC were analyzed by Pearson’s test. (b, c) Genes positively and negatively correlated with MANF in HCC areshown by heat maps (TOP 50). Red dots indicate positively correlated genes, and green and blue dots indicate negatively correlated genes.

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lumen. Overwhelming cellular demand and shortage of cellu-lar energy availability lead to the accumulation of wronglyfolded proteins [22]. Unfolded protein response (UPR) helpscells to reestablish homeostasis by decreasing protein syn-thesis and increasing the folding and clearance capacity of

the ER [23]. Under sustained ER stress conditions, ERhomeostasis mediated by UPR cannot be restored andleads to initiation of apoptosis [24]. However, cancer cellshave evolved UPR to alleviate ER stress conditions as asurvival mechanism for progression [25, 26]. MANF

Pearson-correlation:0.3158P-value:8.432e–10Sample size:(N = 361)

20.00

15.00

10.00UBD

5.00

.008.00 10.00 12.00

MANF14.00

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20.00

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1B10

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MANF14.00

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Pearson-correlation:0.265P-value:3.236e–07Sample size:(N = 361)

18.00

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K

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Pearson-correlation:–0.3048P-value:3.372e–09Sample size:(N = 361)

11.00RB

1

6.008.00 10.00 12.00

MANF14.00

10.00

9.00

8.00

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Pearson-correlation:–0.3493P-value:8.537e–12Sample size:(N = 361)

10.00

BRCA

2

.008.00 10.00 12.00

MANF14.00

8.00

6.00

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Figure 8: Genes correlated with MANF in HCC. (a–c) Correlations between MANF and the top 10 genes including UBD, MDK, andAKR1B10, which have the highest expression multiples in HCC (P < 0:01). (d, e) Correlations between MANF and tumor suppressorgenes RB1 and BRCA2 (P < 0:01).

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protects SH-SY5Y cells against 6-OHDA-induced toxicityby activating the PI3K/Akt/mTOR pathway and alleviatingER stress [27]. ER stress regulated by UPR also plays animportant role in mechanisms of chemotherapy or radia-tion resistance in cancer [28]. MANF is a neurotrophicfactor secreted from cells [29]. Kim et al. have indicatedthat MANF can serve as a urinary biomarker for detectingER stress in podocytes or renal tubular cells [30]. Expressionof MANF has been confirmed to be closely related to ERstress, which is a mediator in the initiation of HCC [16].

The liver is an important organ for the synthesis of pro-teins and lipids, so hepatocyte ER has appropriate adaptivecapacity [31]. When the liver is in a state of inflammationfor a long time, ER stress is maintained at a high level, whichleads to hepatic dysfunction and progression of liver diseases,even HCC [32].

Our study is believed to be the first to explore mRNAexpression and prognostic value of MANF in HCC. Weanalyzed MANF expression in HCC samples using geneexpression and clinical prognostic data in the TCGA, CCLE,EMBL-EBI, GEPIA, LinkedOmics, and ONCOMINE data-bases, clinical specimens from our hospital, and HCC TMAs.We found that MANF was always highly expressed in HCCand many other cancers, indicating the significance ofMANF in tumorigenesis.

Although previous studies have shown that MANF ishighly expressed in HCC, there is a lack of reliable meansto prove the diagnostic value of MANF in HCC. Therefore,we conducted a meta-analysis of MANF expression in previ-ous studies retrieved from the GEO HCC dataset. ROCcurves from GEO datasets were used to confirm the satisfac-tory diagnostic performance of MANF. However, diagnosticperformance of MANF in TMA analysis was not entirelysatisfactory, which may be caused by the subjectivity ofimmunohistochemical staining analysis. Overall, MANFwas shown to be a potential diagnostic marker for distin-guishing between HCC and nontumor tissues.

As shown in the analysis of the GEPIA database andTMA supporting clinical data, MANF is a novel potentialprognostic marker for HCC patients. Consistent with thesefindings, patients with high MANF expression levels had ahigher risk of tumor recurrence. Dysfunction of ER stressand UPR signal underline the resistance of cancer cells tochemotherapy, and ER stress response was inhibited inchemoradiotherapy-resistant cells compared with that insensitive cells [33]. MANF could alleviate ER stress andreduce ER stress-induced cell death, and ER stress activationcould cause upregulation of MANF in vivo and in vitro[13, 34]. The higher recurrence rate and worse prognosismight be due to MANF-ER stress-mediated chemotherapyor targeted drug resistance; it needs further validation.

Our study proved that MANF was upregulated in HCCtissues more than in nontumor tissues. High expression ofMANF was also involved in the development and progres-sion of HCC and a potential indicator in the diagnosis, treat-ment, and prognosis of HCC. In addition, the molecularmechanism involved in MANF expression and occurrenceof HCC remains unknown. In order to study further theimportant role of MANF in occurrence and development

of HCC, more in vitro and in vivo experiments shouldbe conducted.

5. Conclusion

MANF was overexpressed in HCC and related to poorprognosis and progression of HCC. Our results showedthat MANF is a potential diagnostic and prognostic indicatorof HCC.

Abbreviations

HCC: Hepatocellular carcinomaMANF: Mesencephalic astrocyte-derived neurotrophic

factor(ARMET): Arginine-rich mutated in early tumorGEPIA: Gene Expression Profiling Interactive AnalysisNAFLD: Nonalcoholic fatty liver diseaseTCGA: The Cancer Genome AtlasEMBL-EBI: The European Bioinformatics InstituteCCLE: Cancer Cell Line EncyclopediaGEO: Gene Expression OmnibusSMD: Standard mean differenceTMA: Tissue microarrayROC: Receiver-operating characteristic.

Data Availability

The PCR,WB, immunohistochemical staining and their sup-porting clinical data used to support the findings of this studyare available from the corresponding author upon requestbecause the data also forms part of an ongoing study. TheMicroarray Data supporting this META-ANALYSIS arefrom previously reported studies and datasets, which havebeen cited. The processed data are available at Gene Expres-sion Omnibus (GEO) database (http://http://www.ncbi.nlm.nih.gov/geo/). The bioinformation databases data support-ing this study are from previously reported studies and data-sets, which have been cited. The processed data are availableat ONCOMINE (http://www.oncom/ http://ine.org/), GeneExpression Profiling Interactive Analysis (GEPIA) (http://gepi.a.cancer-pku.cn/), Cancer Cell Line Encyclopedia(CCLE) (https://portals.bro http://adinstitute.org/ccle/data),LinkedOmics (http://www.linkedomics.org/admin.php),EMBL-EBI (https://www.ebi.ac.uk).

Conflicts of Interest

The authors report no conflicts of interest in this work.

Acknowledgments

This study was supported by funds from the National Natu-ral Science Foundation of China (81373172 and 81770646)and Natural Science Foundation of Shandong Province(26020105131715).

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Supplementary Materials

Supplementary material is the basic characteristics of 24HCC cohort from GEO supporting meta-analysis in thisstudy. (Supplementary Materials)

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