Objective: To investigate the clinicopathological features of patients with lung cancers associated with epidermal growth factor receptor (EGFR) gene amplification and/or mutations.
Methods: Mutations and amplification status of EGFR gene were detected by PCR-DNA sequencing and FISH, respectively, followed by subsequent clinicopathological correlative studies.
Results: Among 454 patients, the overall mutation rate of EGFR was 48.2% (219/454). The EGFR mutation rate in females was significantly higher than that of males, 59.6% (118/198) vs. 39.5% (101/256), P<0.001. The mutation rate of EGFR gene of non-smokers was higher than that of smokers, 52.7% (147/279) vs. 41.4% (72/175), P=0.017. The mutation rate in patients with adenocarcinoma was higher than that in patients with other cancer types, 56.8% (193/340) vs. 22.8% (26/114), P<0.05. Moreover, a significant difference of mutation rates among different subtypes of adenocarcinomas was found (P=0.001). Among 134 patients with available FISH analysis, no statistical significance of EGFR gene amplification was found in age, gender, histopathological types and subtypes of adenocarcinomas (P>0.05). There was a significant correlation between EGFR mutation and its gene amplification (P=0.0005), although with poor consistency (P=0.275).
Conclusions: EGFR gene mutations occur more frequently in females, non-smokers and patients with adenocarcinoma subtype. A significant variation of the mutation types exits among the subtypes of adenocarcinoma. The presence of EGFR amplification appears not related to age, gender, histopathological types of lung cancer and subtypes of adenocarcinoma. There is a significant correlation between EGFR mutations and its gene amplification (P=0.0005), although with poor consistency.