Expression of ErbB2 and ErbB3 in Non-Small Cell Lung Cancer
M Teresa Salcedo, M Angeles Montero, Javier Hernandez-Losa, Cristina Teixido, Helena Allende, Enriqueta Felip, Nuria Murtra-Garrell, Esther Pallisa, Mercedes Canela, Santiago Ramon y Cajal, Natalia Tallada. University Hospital Vall de Hebron, Barcelona, Spain
Background: In non-small cell lung cancer (NSCLC),EGFR has been studied extensively, but less is known about the expression and role of other ErbB receptors. The aim of this study is to determine ErbB2 and ErbB3 expression in NSCLC.
Design: Expression of ErbB2 (Dako) and ErbB3 (Antibody supplied by A. Pandiella) was analyzed inmunohistochemically using tissue microarrays from tumor samples from 126 patients (median age 67 years,81% males,6% never smokers,p-stage 33% I/29% II/30% III/9% IV),diagnosed with NSCLC (51 adenocarcinoma (ADC)/47 squamous-cell carcinoma (SCC)/28 others), who underwent complete resection between October 2007 and September 2010. Cytoplasmic (cyt) and membranous (mb) staining expression was assessed by two observers as follows:0, no staining;1+,weak,incomplete mb staining;2+,weak to moderate,complete mb staining of at least 30% of tumor cells or strong,complete mb staining of 10-30% of tumor cells; and 3+,strong,complete mb staining of at least 30% of tumor cells. Score of 2+/3+ was regarded as positive.ErbB2 by FISH was analyzed in patients with positive ErbB2 expression.EGFR-mutation (mut) was determined in selected patients (23 cases). Statistical and survival study was performed.
Results: Positive mb ErbB2 expression was found in 5 cases (4%):3 ADC/2 SCC (all males,1 never smoker), all cases were erbB2 FISH negative. Positive ErbB3 mbs and cyt expression was found in 27% and 21% of all cases, respectively; 10.3% of cases expressed both. Positive ErbB3 expression was more frequent in females than in males (mb 46% vs 22%,p 0.038;cyt 33% vs 18%,p 0.099), in ADC than in SCC (mb 36% vs 21%, p 0.07; cyt 32% vs 13%, p 0.014). No correlation was found between ErbB3 expression and age and p-stage. Five of 23 patients had EGFR-mut (2 del exon 19,3 L858R exon 21): all females with ADC,4 never smokers. No EGFR-mut cases had concomitant positive ErbB2. Four out of 5 EGFR-mut patients had positive cyt ErbB3 expression (80%), 3 had mb expression (60%). Preliminary results (median follow-up, 17 months) showed no association between ErbB3 expression and disease-free or overall survival.
Conclusions: Positive ErbB2 expression is infrequent in NSCLC and no correlation is found with EGFR-mut cases. Positive ErbB3 expression occurs more frequently (25% of cases,females, ADC and EGFR-mut tumors). However, ErbB3 warrants further study in NSCLC to clarify its role and its potential use as a therapeutic target.
Wednesday, March 21, 2012 9:30 AM
Poster Session V # 310, Wednesday Morning