The expression levels of BRCA1, TYMS, TOP2A and HER2 were associated with histological type and the expression levels of BRCA1, TYMS and TOP2A were different between adenocarcinoma and non-adenocarcinoma patients (the correlation coefficients of the three genes were 0.419, P=0.000; 0.293, P=0.004; and 0.247, P=0.017, respectively). Here, ERBB2 is linked to adenocarcinoma.