Current evidence on the cytotoxic T-lymphocyte antigen 4 + 49G > A polymorphism and digestive system cancer risks: a meta-analysis involving 11,923 subjects.

Cytotoxic T-lymphocyte antigen (CTLA-4) plays an important role in downregulating T cell activation and proliferation. The CTLA-4 + 49G > A polymorphism is one of the most commonly studied polymorphisms in this gene due to its association with many cancer types, but the association between CTLA-4 + 49G > A polymorphism and digestive system cancer risks remain inconclusive. An updated meta-analysis based on 17 independent case-control studies consisting of 5176 cancer patients and 6747 controls was performed to address this association. Overall, there was no statistically increased risk of digestive system cancers in every genetic comparison. In subgroup analysis, this polymorphism was significantly linked to higher risks for pancreatic cancer (GG vs. AA, OR = 1.976, 95% CI = 1.496-2.611; GA vs. AA, OR = 1.433, 95% CI = 1.093-1.879; GG/GA vs. AA, OR = 1.668, 95% CI = 1.286-2.164; GG vs. GA/AA, OR = 1.502, 95% CI = 1.098-2.054; G vs. A, OR = 1.394, 95% CI = 1.098-1.770). We also observed increased susceptibility of hepatocellular cell carcinoma in homozygote comparison (OR = 1.433, 95% CI = 1.100-1.866) and dominant model (OR = 1.360, 95% CI = 1.059-1.746). According to the source of controls, significant effects were only observed in hospital-based studies (GA/AA vs. GG, OR = 1.257, 95% CI = 1.129-1.399). In the stratified analysis by ethnicity, no significantly increased risks were found in either Asian or Caucasian. Our findings suggest that the CTLA-4 + 49G > A polymorphism may be associated with the risk of pancreatic cancer and hepatocellular cell carcinoma.

Myeloid derived suppressor cells mediated suppress immunity / 国际肿瘤学杂志

There exists a population of myeloid-origin cells that are associated with tumor immune escape in cancer patients,commonly termed as myeloid derived suppressor cells(MDSCs).M DSCs accumulate in the blood,lymph nodes,bone marrow,and inhibit both adptive and innate immunity.Different suppressive mechanisms are used by MDSCs to block tumor immunity.Reducing the numbers of MDSCs or inhibiting the suppressive pathway conducted by MDSCs will bring new highlight to biotherapy in tumor treatment.