Association of GSTT1 & GSTM1 Null Mutations with Breast Cancer Risk in North Indian Population: A Case-Control Study

Abstract

Background: Breast cancer accounts for approximately 25% of cancer cases globally, with varying incidence rates across different regions. Genetic factors, especially mutations in genes such as GSTT1 and GSTM1, play a significant role in influencing breast cancer susceptibility. 
Aim: This research aims to examine the association between null mutations in these genes and breast cancer occurrence in the North Indian population women, through a case-control study. 
Methodology: Conducted between January 2023 and June 2024, this case-control study involved 200 participants, with 100 being breast cancer patients and 100 healthy controls. Blood samples were collected to extract DNA, and polymerase chain reaction (PCR) techniques were used to genotype the GSTT1 and GSTM1 polymorphisms. Statistical analysis, including chi-square tests and the calculation of odds ratios (OR), was performed to assess the association between these gene variants and breast cancer risk. 
Results: The GSTT1-null mutation was not found in any breast cancer cases but appeared in 5% of the control group, indicating a significant protective relationship with breast cancer risk (p = 0.023, OR = 0.014 [0.0008-0.233]). In contrast, the GSTM1-null mutation was present in 26% of the breast cancer cases and 38% of controls, with no statistically significant association (p = 0.068, OR = 0.57 [0.31-1.04]). 
Discussion & Conclusion: This study reveals a significant association between the GSTT1-null mutation and reduced breast cancer risk in North Indian women. However, no significant correlation was observed for the GSTM1-null mutation. These findings underscore the necessity of investigating genetic factors in diverse populations, which may help in the development of more targeted breast cancer prevention strategies.