[Comparison of epidermal growth factor receptor gene mutation in lung adenocarcinoma using biopsied tissue, pleural...

Objective: To compare different specimen types of lung adenocarcinoma in the detection of epidermal growth factor receptor (EGFR) gene and to correlate EGFR mutations with patient clinical features. Methods: One hundred lung adenocarcinoma cases were collected from June to December in 2015, at the First Affiliated Hospital of Xinjiang Medical University.Of the 100 lung adenocarcinoma samples, 43 were male and 57 were female. The age was from 40 to 88 years old, and the average age was 66 years. One hundred lung adenocarcinoma cases were divided equally into two groups. Mutation analysis of EGFR gene by real-time PCR was performed using biopsied tissue and paired blood samples in one group (n=50) and using pleural effusion and paired blood samples in the other group (n=50). Results: The mutation rate of EGFR gene in biopsy samples was 54% (27/50) , higher than that of blood samples (46%, 23/50), but without statistical differences (χ(2)=0.640, P=0.424). In contrast, mutation rate of EGFR gene in pleural effusion samples (42%, 21/50) was higher than that of blood samples (34%, 17/50), but without statistical differences(χ(2)=0.679, P=0.409). Two patients had EGFR mutation detected in paired blood samples but not in the corresponding biopsy samples, and four patients had EGFR mutation detected in pleural effusion samples but not in their paired blood samples. The mean progression-free survival of patients with detectable EGFR mutation were 9.5 months (tissue samples), 8.6 months (pleural effusion) and 8.5 months (blood). However, there was no statistical difference. Conclusions: Blood samples may be used to assess EGFR mutations for patients with lung adenocarcinoma. However, further studies are needed to improve the sensitivity and accuracy in the detection of EGFR mutations using blood samples.