Objective   To investigate the mutations of the epidermal growth factor receptor (EGFR) gene and its clinical significance in non-small cell lung cancer (NSCLC).

  Methods   The EGFR gene mutations of exons 18 to 21 in NSCLC were detected by using the ADx-ARMS^® detection kit method.

  Results   The total mutation percentage in exons 18 to 21 of the EGFR gene was 45.8% (98/ 214) in NSCLC. These mutations predominantly occur in exons 19 and 21. EGFR gene mutation percentages were found in exons 18 (0.93%, 2/214), 19 (22.0%, 47/214), 20 (2.3%, 5/214), and exon 21 (20.6%, 44/214) in the NSCLC. Two NSCLC cases were identified to have double EGFR gene mutations of exons 19 and 21. EGFR gene mutations were more frequently observed with adenocarcinoma histology (50.3%, 93/185) than with squamous cell carcinoma (17.2%, 5/29) (P=0.001). EGFR gene mutations occur more frequently in NSCLC cases in women than in men (P=0.002). EGFR gene mutations were significantly higher in NSCLC with lymphatic metastasis (66.7%) than in NSCLC without lymphatic metastasis (39.5%) (P < 0.05). However, no evident association was found between EGFR gene mutations and age, as well as tumor grade and clinical stage of NSCLC (P>0.05).

  Conclusion   NSCLC, especially lung adenocarcinomas, has exhibits frequent EGFR gene mutations in China. EGFR gene mutations in exons 19 and 21, combined with the clinical pathological features of lung cancer, can serve as the molecular marker to evaluate the efficacy of EGFR TKI for NSCLC patients.