Glutathione S-transferase expression in upper urinary tract urothelial carcinomas: a Taiwan study.
OBJECTIVES This study investigates the usefulness of glutathione-S-transferases (GST) isoenzymes and p53 immunostaining as a marker of malignancy in urinary cytology, and evaluates their potential effect in increasing diagnostic accuracy in a series of urine cytologic samples. They are also correlated with cytopathology diagnosis and histopathologic diagnosis. MATERIALS AND METHODS In this study, the slides from 124 bladder carcinoma patients prepared by the cytocentrifugation method were observed. The cytomorphologic properties of these cancer cells were determined. Moreover, the immunocytochemical distributions of GST alpha (GSTA), pi (GSTP), mu (GSTM4), theta (GSTT1) isoenzymes and p53 protein were studied for the patients. RESULTS The urothelial cancer cells had small cytoplasm and rough nuclear membrane. The chromatin granules were heterogeneously distributed in each malignant cell's nucleus. There was a pleomorphism of the malignant cells' nuclei. According to immunocytopathologic observations, the urothelial cancer cells had stronger staining intensity than the benign cells had in 48% of cases for GSTA, 46% of cases for GSTP, 38% of cases for GSTM4, and 42% of cases for GSTT1. For all papillary cases, the malignant cells were stained negative, while the benign cells were positive. For 83% of patients, the malignant cells were stained positive for p53. There was a significant difference in GSTA (P = 0.006), GSTT1 (P = 0.004), GSTP (P = 0.000) and p53 (P = 0.000) expressions for benign cells whereas, a non-statistical difference in the malignant cells for GSTA, GSTT1, GSTP, GSTM4, and p53 expressions (P > 0.05). CONCLUSIONS GST isoenzymes and p53 immunostaining were not found to be markers of malignancy in urinary cytology.