Glutathione S-Transferase T1 and M1 Gene Polymorphisms among Breast Cancer Susceptible Ghanaians

Author(s): Benjamin Arko-Boham, Emmanuel Ayitey Tagoe, BerniceAdjorogbe, Nii Ayite Aryee, Samuel M Adadey, Osborne Quaye, Joe-Nat Clegg-Lamptey

Background: Glutathione S-transferase (GST) gene polymorphism has been associated with breast cancer; however, there are conflicting results. Little or no information exists in the Ghanaian population.

Aim: To determine the association between GST polymorphic genes (GSTM1 and GSTT1) and susceptibility to breast cancer in Ghanaian population.

Method: 112 whole blood samples were retrieved from -80oC freezer. Samples comprised 56 female breast cancer patients. Demographic and clinical data were retrieved from records. Patients were age matched with 56 controls. Genomic DNA was extracted; GSTTI and GSTM1 genes amplified using multiplex PCR with appropriate primers and the resultant amplicons separated by agarose gel electrophoresis.

Results: The prevalence of GSTT1 null in patients was 42.9% and with greater association with breast cancer (OR=2.84, 95% CI=1.52–5.29, p=0.001). The heterozygous GSTT1 null/GSTM1 genotype was strongly associated with breast cancer (OR=3.02, 95% CI=1.61–5.66, p<0.001). Intriguingly, double deletion of the genes was weakly associated with breast cancer (OR=1.21, 95% CI=0.51–2.84, p>0.05). However, the presence of both genes was not a risk factor of breast cancer in the patients (OR=0.53, 95% CI=0.28–1.09, p=0.030).

Conclusion: The GSTT1 null and GSTT1 null / GSTM1 genotypes may be potential risk factors for breast cancer susceptibility.