[Analysis of EGFR mutations in 176 cases of non-small cell lung cancer]

To analyze the incidence and profile of mutations in epidermal growth factor receptor (EGFR) in Chinese patients with non-small cell lung cancer (NSCLC).

A total of 176 cases of NSCLC tissue was enrolled in this study, among which 123 normal lung samples were also included. The tissue DNA was extracted and the EGFR gene in exon 19 to 21 was subjected for PCR amplification and direct sequencing.

The EGFR gene in exon 19-21 was of wild type in all normal lung tissues detected. Mutations were found in 57 cases of 176 lung cancer samples, with an incidence of 32. 4%. Mutations were mainly detected in the exon 19 (37/57 cases, 64. 9% ) and exon 21 (18/57 cases, 31. 6% ) , while that in the exon 20 was rare (2/57 cases, 3. 5% ). There were 7 types of EGFR mutation in the exon 19, resulting in the deletion of codon 746 to 753. A missense mutation was detected in exon 20, dealing with codon 789 to 793. The mutation in exon 21 belonged to the single missense substitution in codon 858. The EGFR mutations were more frequent in female patients than male ones, in adenocarcinoma and adenosquamous cell carcinoma versus cancer of other histologies.

EGFR mutation is a tumor-specific somatic abnormality. Some one third of Chinese NSCLC tumors harbor EGFR mutations, especially in exons 19 and 21. These mutations are more frequently detected in female, adenocarcinoma and adenosquamous cell carcinoma.