IL-21 gene polymorphism is associated with the prognosis of breast cancer in Chinese populations

Interleukin ( IL )-21, which is secreted by activated CD4 + T cells and NKT cells, has been found to be able to influence the humoral and cell-mediated immune responses and have potent antitumor activity in animal models. This study was to investigate the impact of genetic polymorphisms in IL - 21 on survival of breast cancer. Four TagSNPs of IL - 21 (rs12508721C>T, rs907715G>A, rs13143866G>A, rs2221903A>G) were selected and then genotyped in 891 patients with breast cancer in Eastern and Southern Chinese populations. We then examined the associations between these SNPs and overall survival. Potential function of rs12508721C>T and association between this variation and breast cancer prognosis were further studied. Overall, 121 of the patients had died over the followed-up period of 5 years. The IL - 21 rs12508721T allele predicted longer five-year survival (HR = 0.347, 95 % CI = 0.187–0.644, P