Common epidermal growth factor receptor mutations in north Indian patients with non-small cell lung carcinoma: evidence from real-time polymerase chain reaction

Lung carcinoma was the most common cause of cancer deaths globally in 2022, with non-small cell lung carcinoma (NSCLC) accounting for 81% of the burden. Due to promising tyrosine kinase inhibitor (TKI) trials, NSCLC patients harboring EGFR gene mutations are of interest. Our aim was to determine EGFR mutation prevalence in north India and its histologic and demographic correlations. We investigated the frequency of EGFR mutations in 40 patients with histologically confirmed NSCLC using real-time polymerase chain reaction. A 15% mutation frequency was observed in the study sample, involving 32 males and 8 females with a median age of 59 years. Squamous cell carcinoma (SCC) patients had only EXON20 (T790M, exon20 insertion) mutations, while adenocarcinoma patients had mutations in both EXON20 (T790M) and 21 (L858R) with mutation frequencies of 22% and 10%, respectively. 28% of the SCC patients were non-smokers, and 60% of these non-smokers had an EGFR mutation. South Indian and Asian studies have identified EXON19 (19-Del) and EXON21 (L858R) mutations as "common mutations" that account for nearly 80-90% of all mutations and respond well to TKIs. Interestingly, "common mutations" were found seldom in our study population, while the uncommon variants constitute 83% of all mutations, which we assume is due to diverse Indian genetics and ethnicity and co-existing signature mutations that involve the tyrosine kinase domain of EXON20. We suggest future genome-wide association studies to identify plausible genetic polymorphisms responsible for interethnic differences in EGFR mutation, which will contribute to better treatment and prevention of NSCLCs.