The -174G>C and -596G>A Polymorphisms Are Not Associated with Circulating IL-6 Levels in Breast Cancer Patients from Jalisco, México

Introduction: Interleukin-6 (IL-6) is a circulating proinflammatory cytokine that fulfills an important role in the survival and proliferation of cancer cells. Overexpression of IL-6, possibly due to the -174G>C and -596G>A polymorphisms in the IL6 gene, has been shown to be related to breast cancer (BC) and a more aggressive course of the disease. Aim: To determine the influence of the -174G>C and -596G>A polymorphisms of the IL6 gene on the circulating levels of IL-6 in BC patients from Jalisco, México. Methodology: Genotyping of the two polymorphisms was carried out on 208 BC patients and 219 healthy controls through polymerase chain reaction-restriction fragment length polymorphism analyses. In addition, the plasma IL-6 concentration levels were measured in the BC patients. Results: There was no significant association between BC and the IL-6 alleles and genotypes (-174G>C, p = 0.276; -596G>A, p = 0.762) under study. Similarly, there were no significant differences in the mean plasma IL-6 concentrations associated with the polymorphisms that were analyzed (-174G>C, p = 0.839; -596G>A, p = 0.848). Conclusions: No evidence was found that the analyzed polymorphisms are associated with the IL-6 expression or concentration in patients suffering from BC from Jalisco, Mexico.

HLA-G 14 bp Ins/Del (rs66554220) Variant Is Not Associated with Breast Cancer in Women from Western Mexico

HLA-G is a physiology and pathologic immunomodulator detrimentally related to cancer. Its gene is heavily transcriptionally and post-transcriptionally regulated by variants located in regulator regions like 3'UTR, being the most studied Ins/Del of 14-bp (rs66554220), which is known to influence the effects of endogen cell factors; nevertheless, the reports are discrepant and controversial. Herein, the relationship of the 14-bp Ins/Del variant (rs66554220) with breast cancer (BC) and its clinical characteristics were analyzed in 182 women with non-familial BC and 221 disease-free women as a reference group. Both groups from western Mexico and sex-age-matched (sm-RG). The rs66554220 variant was amplified by SSP-PCR and the fragments were visualized in polyacrylamide gel electrophoresis. The variant rs66554220 was not associated with BC in our population. However, we suggest the Ins allele as a possible risk factor for developing BC at clinical stage IV (OR = 3.05, 95% CI = 1.16-7.96, p = 0.01); nevertheless, given the small stratified sample size (n = 11, statistical power = 41%), this is inconclusive. In conclusion, the 14-bp Ins/Del (rs66554220) variant of HLA-G is not associated with BC in the Mexican population, but might be related to advanced breast tumors. Further studies are required.