Glutathione S-transferases activity in patients with colorectal cancer

Objectives: The glutathione S-transferases (GSTs) play a critical role in protecting the colorectal mucosa. We investigated the efficacy of using the GSTs activity of plasma as a biomarker of risk for colorectal cancer. Methods: GSTs activity was measured in the plasma of control individuals (n = 39) and in the plasma, tumor tissue and normal tissue adjacent to a tumor of patients with colorectal cancer taken at colonoscopy (n = 60). Results: Mean GSTs activity was significantly (P < 0.01) higher in tumors (242 ± 45 nmol/min mg protein) as compared to normal tissues adjacent to a tumor (84 ± 49 nmol/min mg protein). A significant correlation between normal tissues adjacent to a tumor GSTs with those in malignant tissues was observed (r = 0.61). Plasma GSTs activity was significantly (P < 0.0001) higher in colorectal cancer patients (164 ± 11 nmol/min mL) than those obtained from normal individuals (92 ± 23 nmol/min mL). Conclusions: GSTs measurement may be useful as a colorectal cancer marker in colorectal cancer, and biopsies obtained at colonoscopy can be used to measure tumor markers.