Glutathione S-transferases (GSTs) are involved in the detoxification of carcinogens, and may be linked to carcinogenesis. As a vital component of GSTs, GSTA1 plays an important role in carcinogenesis. GSTA1 expression may be a target molecule in early diagnosis and treatment of lung cancer. Human colonic adenocarcinoma (Caco-2) cells in culture undergo spontaneous differentiation into mature enterocytes in association with progressive increases in expression of glutathione S-transferase alpha-1 (GSTA1). GSTA1 levels may play a role in modulating enterocyte proliferation but do not influence differentiation or apoptosis. GSTA1 may play a key role during pregnancy.