Coordinatore: Gaetano Finocchiaro, Fondazione IRCCS Istituto Neurologico Besta

Unità Operative:• Istituto Neurologico Besta, Gaetano Finocchiaro (Unità Neuro-Oncologia

Sperimentale)• Istituto Europeo di Oncologia, Maria Rescigno (Dip. Oncologia Sperimentale)• Istituto Nazionale Tumori Regina Elena, Carmine Carapella (Dip. Neurochirurgia)

Ciardiello and Tortora, 2008

Friedman and Bigner, 2005

The radiation-induced 8.5-foldactivation of the pro-proliferative mitogen-activated protein kinase and the 3.2-fold stimulation of the antiapoptotic AKT/phosphatidylinositol-3-kinase pathways by EGFRvIII far exceeded that in CHO.EGFR wt cells. Thus, based on colony formation and apoptosis assays, EGFRvIII expression conferred a stronger cytoprotective response to radiation than EGFRwt, resulting in relative radioresistance.

Expression of the constitutively active mutant EGFRvIII promotes changes in cell shape and focaladhesion formation, mediated in part through specific modulation of integrin A2 expression and function. We conclude that EGFR-activating mutations, such as EGFRvIII, in ovarian cancer may contribute to a more aggressive disease.

In our study, we detected the presence of EGFRvIII mRNA and revealed a high incidence (67.8%) of EGFRvIII transcript in human primary invasive breast cancer by utilizing laser capture microdissection (LCM)/RT-PCR to capture pure breast cancer cells. In addition, 57.1% of the infiltrating breast carcinomas expressed both EGFRwt and EGFRvIII mRNA in the same tumor. There is no detectable EGFRvIII mRNA in normal breast tissue. Evaluation of the EGFRwt and EGFRvIII protein levels in the same sample sets by immunohistochemical analysis further confirmed the LCM/RT- PCR finding.

EGFRvIII mRNAwas identified by an RT-nested PCR with a high sensitivity. In 102 women studied, the mutant was detected in the peripheral blood of 30% of 33 low risk, early stage patients, in 56% of 18 patients selected for neoadjuvant chemotherapy, in 63.6% of 11 patients with disseminated disease and 0% of 40 control women (Silva et al, 2006).

Immunohistochemical Detection of EGFRvIII in High Malignancy Grade Astrocytomas and Evaluation of Prognostic Significance

Aldape et al, 2004

Kaplan-Meier estimates of overall survival in patients who underwent gross-total resection and radiation therapy and have survived for >1 year. Patients with tumors not expressing the EGFR (n = 38; solid black line), expressing amplified EGFR (n = 19; dashed grey line), and expressing EGFRvIII (n = 32; dotted black line) had median overall survival times of 2.03 (95% CI, 0.50-3.56), 2.02 (95% CI, 1.58-2.46), and 1.21 (95% CI, 1.06-1.36), respectively.

Kaplan-Meier survival curves of all assessable glioblastoma patients in this study (n =509) stratified by epidermal growth factor receptor variant III (EGFRvIII)/YKL-40 status. The absence of both markers in tumors (n =81, blue) conferred a favorable survival advantage when compared with all of the other groups (all P< .001, log-rank test). There were no differences in survival times between the following three unfavorable groups: YKL-40–positive only patients (n= 282, gray); EGFRvIII-positive only patients (n =36, red); and both EGFRvIII and YKL-40–positive patients (n =110, yellow; all P >.588, log-rank test).

Courtesy of E. Maderna and B. Pollo

Peak EGFR Positive control

Peak EGFR Negative control

Peak IFNG Positive control

Peak IFNG Negative control

Positive control

Negative control

Courtesy of Sara Guzzetti

Peak EGFR SDP in December Surgery

Peak EGFR SDP in April surgery

Peak IFNG SDP in December surgery

Peak IFNG SDP in April Surgery

SDP April surgery

SDP December surgery

Courtesy of Sara Guzzetti

EGFR amplification as one way of resistance to bevacizumab?

Sample Name Marker IFNG IFNG-ht EGFR EGFR-ht Allele ratioEGFR/IFNG Comment

Negative control EGFR 77.67 831 108.15 919 1.11 No amplification

Positive control EGFR 77.68 448 108.12 2948 6.58 Amplification

SDP (April) EGFR 77.69 1053 108.13 1803 1.71 No amplification

SDP (December) EGFR 77.69 254 108.12 5316 20.93 Amplification

Courtesy of Sara Guzzetti