Superoxide Dismutase (rs2070424, rs4880, rs2536512) and Catalase (rs794316, rs1001179) SNPs and their Association with Breast Cancer Risk: Findings from a Hospital Based Case-Control Study.

BACKGROUND

The antioxidant enzymes are important cellular components involved in detoxification of reactive oxygen species (ROS) and protect cells from ROS induced oxidative damage. Single nucleotide polymorphisms (SNPs) of antioxidant enzyme coding genes such as superoxide dismutase (SOD) and catalase (CAT) may alter the enzyme activity which can influence susceptibility towards carcinogenesis.  Therefore, the present study was planned to investigate possible SNPs of SOD (SOD1 (Cu,Zn-SOD), SOD2(Mn-SOD), SOD3(EC-SOD) and CAT genes and their possible association with breast cancer risk in rural Indian women.

METHODS

In this case-control study, the association of SOD and CAT gene polymorphism was studied by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The study was conducted among 400 clinically breast cancer patients and 400 healthy women in a population of South-Western Maharashtra. The logistic regression analysis was carried out to calculate Odds ratio (OR) with 95% confidence interval and p-value, where p ≤0.05 was considered as statistically significant.

RESULTS

The results of analysis of genotype frequency distribution showed significant association of rs4880 SNP of Mn-SOD with BC risk at homozygous variant (CC/CC) genotype (OR 2.46; 95%CI, 1.61-3.75; p<0.0001) and corresponding frequency of variant (C) allele (OR 1.53; 95%CI, 1.25-1.86; p<0.0001). In CAT gene polymorphisms the variant (T/T) was increased significantly in BC cases as compared to controls (OR 3.45; 95%CI, 2.17-5.50; p<0.0001) along with its variant (T) allele (OR 2.01; 95%CI, 1.63-2.48; p<0.0001).

CONCLUSIONS

The results implied that, C/C genotype of SOD2-1183T/C polymorphism and T/T genotype of CAT-262 C/T polymorphism may be associated with an increased breast cancer risk. However, SOD1-251 A/G and SOD3-172 G/A polymorphisms did not show any significant difference in variant homozygous genotypes of patients compared to controls.