The expression of GST and CYP isoenzymes in thyroid nodular hyperplasia and papillary thyroid cancer tissue: Correlation with clinical parameters

Abstract

This study investigated the immunohistochemical staining characteristics of glutathione-S-transferase (GST) pi(P), mu(M), theta(T), omega(O) and kappa(K) cytochrome P450 (CYP) A1, B1 and 2E1 isoenzymes in thyroid nodular hyperplasia (NH) and papillary thyroid cancer (PTC) tissues. For immunohistochemical studies, tissues from 18 patients with thyroid nodular hyperplasia, 28 patients with papillary thyroid cancer at the Kecioren Training and Research Hospital, Ankara, Turkey, were used. Relationships between GST and CYP isoenzyme expressions in NH and PTC tissues were examined by the Mann-Whitney U test, and clinicopathological data were examined by the Pearson Correlation Test and Regression Analysis. When the NH and PTC tissues from these cases were compared with respect to their staining intensity, GSTP1, GSTO1, GSTK1, CYP1A1, CYP2E1 expressions in PTC cells were significantly higher than those in NH epithelial cells (p< 0.05). There were no statistically significant differences in the CYP1B1, GSTT1 and GSTM1 expressions between benign and tumor epithelium (p> 0.05). There were significant association between GSTO1, GSTK1 expressions and sT3 levels in PTC (p< 0.05) and CYP1B1 expression in NH. There was a significant association between GSTO1 expression and smoking status in NH ( p< 0.05). There was no statistical relationship between the GSTM1, GSTT1, GSTP1, GSTO1, GSTK1, CYP1A1, CYP1B1, CYP2E1 isoenzyme expressions and the clinicopathological data (age, TSH, sT4 levels, tumor stage) ( p> 0.05). GSTP1, GSTO1, GSTK1, CYP1A1 and CYP2E1 isoenzymes may have roles in the carcinogenesis of the papillary thyroid cancer.