The present study investigated the association between the G(-248)A single nucleotide polymorphism (SNP) in the promoter region of B-cell lymphoma 2 (Bcl-2) associated X protein (Bax), which is a pro-apoptosis gene and the clinicopathological parameters and prognosis of patients with esophagus cancer. Three genotypes (AA, AG and GG) of Bax G(-248)A SNP were detected in 75 patients with esophageal squamous cell carcinoma (ESCC) via polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP). The expression of Bax in tumor tissues from 75 patients with ESCC and 30 para-carcinoma normal tissues were detected via immunohistochemistry. The association between the Bax protein expression and the Bax gene polymorphism was analyzed via the χ2 test. The clinical data of patients was collected and the association between Bax gene polymorphism and the pathological parameters and the prognosis of patients with ESCC was analyzed. The PCR-RFLP results revealed that the number of cases and the distribution frequencies of GG, AG and AA genotypes of Bax polymorphism in patients with ESCC were 50 (66.67%), 16 (21.33%) and 9 (12%), respectively. The immunohistochemical results revealed that the positive expression rate of Bax in ESSC tissues was 42.67%. Bax protein expression was associated with the Bax gene polymorphism, which was associated with outer membrane infiltration, differentiation degree, lymphatic metastasis and the clinical staging of patients. The overall 5-year survival rate of patients was 38.6% (29/75). The survival analyses revealed that the prognosis of patients with AG+AA genotypes was favorable, while that of patients with GG genotype was poor. Bax gene polymorphism was associated with Bax gene expression, tumor staging and lymphatic metastasis in patients with ESCC, which is an influencing factor for the overall survival rate and may be used as a reference index for the prognosis evaluation of patients with ESCC.
Keywords: B-cell lymphoma 2 associated X protein; esophageal squamous cell carcinoma; gene polymorphism; prognosis.