Heterozygote of TAP1 Codon637 decreases susceptibility to HPV infection but increases susceptibility to esophageal cancer among the Kazakh populations

BACKGROUND The role of human papillomavirus (HPV) may be involved in the development of esophageal cancer (EC) and the polymorphic immune response gene transporter associated with antigen processing (TAP) may be involved in HPV persistence and subsequent cancer carcinogenesis. The current study aims to provide association evidence for HPV with EC, to investigate TAP1 polymorphisms in EC and assess its association with HPV statuses and EC in Kazakhs. METHODS The HPV genotypes in 361 patients with EC and 66 controls selected from Kazakh population were evaluated using PCR. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed to detect two SNPs of TAP1 in 150 cases comprised of 75 HPV(+) and 75 HPV(-) patients and 283 pure ethnic population of Kazakh and evaluate their associations with susceptibility to EC. A case-to-case comparison based on the genotyping results was conducted to address the function of TAP1 variants in the involvement of HPV. RESULTS The presence of four HPV genotypes in EC tissues - including HPV 16, 18, 31, 45 - was significantly higher at 64.6 % than those in controls at 18.2 % (P < 0.001). Such presence was strongly associated with increased risk of EC (OR 8.196; 95 % CI 4.280-15.964). The infection of HPV16, and multi-infection of 16 and 18 significantly increase the risk for developing EC (OR 4.616, 95 % CI 2.099-10.151; and OR 6.029, 95 % CI 1.395-26.057 respectively). Heterozygote of TAP1 D637G had a significantly higher risk for developing EC (OR 1.626; 95 % CI 1.080-2.449). The odds ratio for HPV infection was significantly lower among carriers of TAP1 D637G polymorphism (OR 0.281; 95 % CI 0.144-0.551). CONCLUSIONS HPV infection exhibits a strong positive association with the risk of EC in Kazakhs. Heterozygote of TAP1 D637G decreases susceptibility to HPV infection in patients with EC but increases susceptibility to EC among the Kazakh populations.