Objective: To investigate EGFR mutations and gene copy number status in non-small cell lung carcinomas in the Chinese patients.
Methods: Using formalin fixed and paraffin embedded tissue samples, EGFR mutations were investigated in 290 cases of non-small cell lung carcinomas by microdissection and scorpions amplification refractory mutation system. The status of EGFR gene copy number was investigated by FISH. Furthermore, the relationship between EGFR mutations and gene copy number, and the relationship between EGFR gene status and clinicopathological variables of non-small cell lung carcinoma were analyzed.
Results: The overall mutation rate of EGFR was 41.7% (121/290). The mutation rates in adenocarcinoma, large cell carcinoma and squamous carcinoma were 48.4%, 16.7% and 0, respectively. Ninety-two of 121 cases with mutations had exon 19 deletion and L858R mutation, and 6 tumors contained both types of the mutation. The overall FISH positive rate of EGFR was 51.2% (107/209). FISH positive rates in adenocarcinoma, large cell carcinoma and squamous carcinoma were 52.1%, 75.0% and 11.1%, respectively. Therefore, EGFR mutations mainly occurred in the adenocarcinoma, and was significantly correlated with EGFR high copy number.
Conclusions: There are higher EGFR mutation rate and FISH positive rate in non-small cell lung carcinoma in Chinese patients. Combined analysis of EGFR mutation and gene copy number by FISH may provide a superior approach in selecting patients who may benefit anti-EGFR target therapy.