Mutation Analysis of Epidermal Growth Factor Receptor Gene in Non-Small Cell Lung Cancer for Selection of Patients Eligible for Tyrosine Kinase Inhibitor Therapy

Introduction: Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor therapy is effective as a first-line treatment of advanced non-small-cell lung cancer (NSCLC). This research study investigated the distribution of EGFR mutations in patients diagnosed with NSCLC to assist in selecting patients who could benefit from tyrosine kinase inhibitor therapy. Materials and Methods: This cross-sectional study was conducted between July 2017 and November 2022. A real-time multiplex ​Polymerase Chain Reaction (PCR) assay supplied by Roche Diagnostics was used to examine DNA obtained from 682 tumor biopsies collected from NSCLC patients. DNA amplification was performed in a Cobas z 480 instrument for mutation analysis. The PCR assay was designed using specific primers and probes to detect 43 different mutations targeting exons 18-21. Results: Among the 682 samples, 466 (68.3%) were males, and 216 were females. The male-to-female ratio was 2.1. Twenty per cent of the male and 37% of the female samples were positive for EGFR mutations. The most common mutations were the in-frame deletion of exon 19, followed by L858R in exon 21, exon 20 insertion and S769I, exon 18 G719X. In addition, three mutations, namely del exon 19, T790M and exon 20 insertions were also detected in a patient, suggesting an actively progressive disease. Conclusions: This study showed that EGFR mutations are more common in Pakistani female patients than males. Secondly, in-frame deletion of exon 19 and exon 21 mutation L858R are prevalent in most of the NSCLC patients. The prevalence of common and rare EGFR mutations in Pakistani patients provides an opportunity for a subset of patients' chance of therapy.