The Investigation of Functional Genetic Variation in COMT Gene Promoter (rs2020917 & rs2075507) in Iranian Patients with Breast Cancer

Catechol-O-methyltransferase (COMT) gene is one of the genes involved in estrogen metabolism, which plays a role in the detoxification of estrogen metabolites. Gene polymorphisms can affect the expression of the enzyme and contribute to the incidence of breast cancer.

Two functional polymorphisms, rs2020917 and rs2075507, were studied in the position of COMT gene promoter with the potential for breast cancer.

In the present case-control study, 103 women suffering from breast cancer and 100 healthy women were selected within the same age range. After blood sampling, the DNA of samples was extracted by the saturated salt method. Then, the specimens were amplified with specific primer and determined by genotype RFLP-PCR method.

The two groups were similar in terms of age in the spectrum, but they had a significant difference in body mass index (BMI). GG mutant genotype of rs2075507 polymorphism indicated a statistically significant relationship between the two groups and increased the risk of breast cancer by 2.27%. The rs2020917 polymorphism showed no difference between the two groups, but it had a significant relationship with BMI. A combination of the genotypes showed that the individuals carrying GG/CC genotypes increased the risk of breast cancer in their body by a factor of 2.45.

The results from two functional polymorphisms in the distal promoter of COMT gene indicated the relationship between rs2075507 and the risk of breast cancer, and rs2075507 mutant genotypes and wild rs2020917 genotype were highly susceptible to breast cancer. BMI was significantly different between the two groups and also with rs2020917 polymorphism. Further studies in this area will provide stronger results.