Assessment of glutathione-S-transferase and glutathione reductase in patients with squamous-cell carcinoma of buccal mucosa

Serum and tumor cytosolic levels of glutathione-S-transferase (GST) and glu tathione-reductase (GR) activity were determined spectrophotometrical ly. T he levels were correlated with clinicopathological criteria and a tobacco-a ssociated protein band (T band) found in serum. The results showed signific antly decreased mean serum GST levels (p < 0.02) in cancer patients as comp ared with controls. However, mean serum GR levels were significantly higher in patients than in controls (p < 0.01). T-band-positive patients showed l ow GST and low GR activity as compared with T-band-negative patients. Tumor cytosolic-enzyme levels of GST and GR activity were significantly higher ( P < 0.0003 and p < 0.0001, respectively) than in corresponding adjacent non cancerous mucosa. Tumour cytosolic GST and GR activity showed significant a ssociation with clinicopathologic criteria, e.g., stage, histologic grade a nd nodal involvement. T-band-negative patients showed significantly higher levels of GST (p < 0.0001) than did T-band-positive patients. Low levels of cytosolic GST may be associated with increased susceptibility towards carc inogen-induced damage. The results suggest that the presence of T band in t he sera may be associated with a high-risk phenotype due to decreased detox ification ability. (C) 1999 Wiley-Liss, Inc.