Immunohistochemical Localization of Glutathione S-Transferase Isoenzymes (GSTA, GSTP, GSTM4, and GSTT1) and Tumour Marker p53 in Matched Tissue from Normal Larynx and Laryngeal Carcinoma: Correlations with Prognostic Factors

Abstract

Objective: The immunohistochemical staining characteristics of glutathione S-transferase (GST) alpha (GSTA), pi (GSTP), mu (GSTM4), and theta (GSTT1) and P53 were investigated in laryngeal squamous cell carcinoma (LSCC) cases and normal laryngeal tissue from 46 patients. The relationships between expression of the GST isoenzymes and some clinicopathologic features were also examined. Patients and Methods: For immunohistochemical studies, tissues from 46 patients with LSCC at the Dr. Lutfi Kirdar Kartal Education and Research Hospital were used. The relationship between expression of the GST isoenzymes and P53 in normal and tumour tissue was analyzed using the Wilcoxon signed rank test. The correlation between GST isoenzymes and P53 and clinicopathologic data was also examined using the Spearman rank test. Results: When the normal and tumour tissues of these cases were compared according to their staining intensity and percentage of positive staining, GSTA expression in normal cells was significantly higher than in tumour cells, and GSTP and P53 expression was higher in tumour cells (p < .05). GSTM and GSTT1 expression was higher in normal cells; however, the statistical significance was low (p > .05). There was no correlation between P53 and GST expression in patients with LSCC. When the immunohistochemical results of GST isoenzymes and P53 were correlated with the clinical parameters, GSTA expression was increased in poorly differentiated laryngeal tumour, but GSTM4 and GSTT1 expression was decreased (p < .05). Conclusion: According to these results, GST-A, -P, and T1 and P53 were important in the diagnosis of LSCC.