Objective: To explore the relationship between the mutations of epidermal growth factor receptor (EGFR) gene and clinicopathological characteristics in patients with non-small cell lung cancers (NSCLC).
Methods: Paraffin-embedded tissue specimens were obtained from 1444 patients with NSCLC. The genomic DNA was extracted. Mutations of EGFR gene (exons 19 and 21) were detected by real-time PCR.
Results: DNA was available in 1410 cases. Somatic mutations of the EGFR gene were identified in 401 cases (27.8%). Among patients with EGFR mutations, 41.4% (n=166) had del E746-A750 of exon19, 6.7% (n=27) had del L747-P753insS of exon 19, 50.3% (n=201) had L858R of exon 21, and 1.5% (n=6) had L861Q of exon 21. Woman, non-smoker and adenocarcinoma showed a higher percentage of EGFR mutation (43.2%, 37.6%, and 33.5%, respectively). However, there was no association among age, grades, lymph node metastasis, and TNM stages (P>0.05). The mutation rate of BAC subtype (61.3%, 19/31) and adenocarcinoma with BAC features (48.0%, 12/25) was significantly higher than that of conventional adenocarcinoma (32.4%, 336/1038). A further assess of the smoking status found a trend that the more increased smoking exposure, the lower the incidence of EGFR mutations. A multivariable analysis revealed that adenocarcinoma, never smoking, and female were independently associated with EGFR mutations (odds rations=3.381, 2.393, and 1.727, respectively).
Conclusions: The detection rate of EGFR mutation is higher in Chinese patients, especially in non-smoking female patients with adenocarcinoma. Real-time PCR is a sensitive and accurate method to detect the mutations of EGFR gene and can therefore provide useful information for clinical treatment.