Evaluation of Epidermal Growth Factor Receptor Gene Mutations in an Iranian Population with Non-Small Cell Lung Carcinoma

Mutations of the epidermal growth factor receptor (EGFR) gene, predominantly in exons 18-21, have been highlighted to function as the crucial predictors of the response rate of patients with non-small cell lung cancer (NSCLC) to EGFR tyrosine kinase inhibitors (TKIs).

This study was performed at Tehran University of Medical Sciences. Data and information were retrospectively collected from the period between Dec 2010 and Apr 2014. Exons 18 to 21 of the EGFR were analyzed for any potential mutation by PCR, accompanied by DNA sequencing on 160 with pathological confirmation of NSCLC.

Demographically, the male to female ratio was approximately 2:1, and a substantial difference in age between sexes was not observed (P=0.065), but a noticeable difference was found in the smoking variable, where 77.8% of males were smokers compared to 17.3% of women (odds ratio (OR) (95% CI) = 16.72 (7.15-39.11)). We found a frequency of 10.63% (17/160) for mutations found in exons 19 and 21, nonetheless, no mutations in exon 18 and exon 20 were observed. The most frequently observed mutations were c.2235_2249, del and c.2240_2257, del in exon 19 and p. L858R in exon 21. The c.2253A>G was found as a novel mutation that was the rarest mutation detected in this work. Interestingly, a remarkable negative association was revealed between smoking and mutation rates in NSCLC patients (OR (95% CI) = 0.13 (0.04- 0.46).

The occurrence of EGFR mutations is largely varied among the different states of Iran, probably due to variations in ethnicity, smoking rate, and sex ratio of participants.