Epidermal growth factor receptor mutation in non-small-cell lung carcinomas: A retrospective analysis of 1036 lung cancer specimens from a network of tertiary cancer care centers in India

Background: Epidermal growth factor receptor (EGFR) mutation plays a vital role in the prognosis of patients with lung cancer. However, there is a dearth of studies on EGFR mutation in Indian population. In this retrospective study conducted at a network of tertiary cancer care centers across India, we evaluated the proportion of EGFR mutation in patients with non-small-cell lung carcinomas (NSCLC). Materials and Methods: A total of 1036 cases of non-small lung cancer were assessed for EGFR mutation status using Scorpion amplified refractory mutation system real time polymerase chain reaction method from fine needle aspiration cytology core biopsy, pleural fluid and cell blocks. For a few cases, macro dissection of tumor from H and E slides was also performed for EGFR analysis. EGFR Status was assessed for the most commonly known driver mutations in Exons 18, 19, 20 and 21, which contributes to a total of 29 somatic mutations including the resistance mutation T790M. Results: Around 39% of the cohort was female and 61% were male. Mutation was positive in 40.3% and negative (wild type) in 59.7%. There was 1.8% mutation in exon 18, 24.6% in exon 19, 1.6% in exon 20 and 12.8% in exon 21. 38.2% had a mutation in a single site and 1.1% had a mutation in two sites. Overall mutation was significant in females (50.5% vs. 33.9%) compared with males ((2) = 28.3, P < 0.001). Mutation was significant in exon 21 (16.8% vs. 10.3%, (2) = 9.44, P = 0.002) and exon 19 (30.7% vs. 20.7%, (2) = 13.2, P < 0.001) in females compared with males. Conclusion: EGFR is expressed differentially/mutated in patients with NSCLC. Further studies to unravel the predictors for acquired genetic alterations of EGFR are needed.