Epidermal growth factor receptor mutations in adenocarcinoma lung: Comparison of techniques for mutation detection

Background: Targeted therapy using tyrosine kinase inhibitors in cases of non-small-cell lung carcinoma (NSCLC) that harbor epidermal growth factor receptor (EGFR) mutations has drastically improved the overall survival rate. The current study estimated the frequency of EGFR mutations in the Indian population by analyzing the diagnostic parameters of various techniques available for the detection of these mutations. Materials and Methods: A case series of 100 histologically diagnosed and immunohistochemically confirmed NSCLC with the adenocarcinoma phenotype comprises the study sample. EGFR mutations were detected using clone-specific immunohistochemistry (IHC), real-time polymerase chain reaction (PCR), and Sanger sequencing. Results: EGFR mutations were identified in 48% cases with 72.78% mutations involving exon 19. Clone-specific IHC had a low sensitivity of 46.43%, and the specificity was 79.17%. Sanger sequencing yielded interpretable results in 16% cases only, which were in concordance with the results of real-time PCR. Conclusion: EGFR mutations are increasingly being explored for targeted therapy and personalized medicine. Real-time PCR was found to be the best and the most accurate method for the detection of somatic EGFR mutations in adenocarcinoma primarily in the lungs.