Possible Association between Resistin Gene -420 C/G Polymorphism and Its Expression and Clinicopathology in Women with Breast Cancer

Breast cancer begins in any part of the breast, caused by abnormal cell growth and division. The adipose tissue is metabolically and immunologically active, which may provide the link between obesity and breast cancer. The Resistin gene is located on chromosome 19p13.3 and 12.5 kDa protein, mainly expressed by macrophages in humans. To explore the relationship between resistin gene -420 C/G polymorphism and breast cancer in south India, We genotyped 154 patients with breast cancer and 142 healthy control subjects, using a PCR-RFLP method. We have also analyzed the gene expression of the resistin gene in 30 breast carcinoma tumours and corresponding control tissues. Gene expression analyses were performed at the mRNA level by RT-PCR. Genomic DNA was isolated by the salting-out method from the tissue samples of the cases and peripheral blood samples of the control group. The quantity of recovered DNA was determined spectrophotometrically. The frequencies of RETN C4-20C, C-420G and G-420G were 83.5%, 17.8%, and 1.4% in the breast cancer group and 89.5%, 4.0% and 0.0% in the control group. The results of our study indicate that the 420 C/G genotype showed 2.6-fold increased risk of breast cancer (p = 0.05). Whereas individuals with joint genotypes (CG/GG) showed 1.79-fold increased risk of breast cancer. In our study, we have also clearly found significantly higher expression in breast cancer tissues in comparison with control tissues (P =0.002). The incidence of breast cancer cases and a control group was higher in the age groups 41-50 years when compared to other age groups, and the incidence was very low in the age group 61-70 years. The frequency of overweight and obese patients and control showed a high Body Mass Index (BMI). In conclusion, our results suggest that resistin gene -420 C/G polymorphism is significantly associated with the risk of breast cancer in obese women. However, there was a significant association between resistin expression levels and -420 C/G polymorphism in the patients. The -420 C/G polymorphism may play a role in inducing breast cancer risk by altering the expression level of the resistin gene.