Objective: To investigate mutations of epidermal growth factor receptor (EGFR) exon 19 and 21 in non-small cell lung carcinoma and to explore their clinicopathological correlations.
Method: DNA was extracted from the excised tumor specimens of 66 non-small cell lung carcinoma patients by traditional phenol-chloroform and ethanol precipitation. Exons 19 and 21 were amplified by polymerase chain reaction (PCR), followed by direct sequencing in both sense and antisense directions.
Results: EGFR somatic mutations were present in 11 of 66 patients (16.7%), including 7 cases of in-frame deletion involving exon 19 and 4 cases of amino acid substitution involving exon 21. Mutations were more frequently observed in women (9/34, 26.5%) than in men (2/32, 6.3%), in adenocarcinomas (10/43, 23.3%) than squamous (0/13) and adenosquamous carcinomas (1/10). There was no difference in the mutation rates between smokers and non-smokers. Those with adenocarcinoma with bronchiolo-alveolar carcinoma (BAC) components had higher frequency of EGFR mutation (6/11) than those without non-BAC element (4/32, 12.5%).
Conclusions: The mutations appear to occur in highly selected subgroups of lung cancer patients: adenocarcinomas with BAC components and patients of the female gender. The results may offer practical approach to the rapid identification of lung cancer patients who likely respond to EGFR inhibitor therapy.