Expression Levels of Glutathione S-Transferase and Cytochrome P450 Isoenzymes in Nasal Polyp Tissue

Nasal polyps are benign sinonasal masses composed of eosinophils and extracellular edema. Pathogenesis of the polyp formation is unclear but several studies strongly suggest a correlation with infection, inflammation and allergy conditions. Our aim is to investigate the potential link between allergy and nasal polyp in tissue level. Nasal polyp group included 60 patients whose diagnosis was confirmed with biopsy and the control group included 38 healthy patients. Tissue sample of the control group was taken from inferior turbinate mucosa under local anesthesia and nasal polyp tissue was collected from functional endoscopic sinus surgery. The glutathione S-transferase (GST) and cytochrome P450 (CYP) isoenzyme expressions of the tissue samples were investigated under light microscopy and graded by a senior pathologist. GSTP1 protein expression was significantly higher in tissue samples from nasal polyp group compared to that of control group (p < 0.05). However, CYP1A1, GSTM1 and GSTA1 isoenzymes were not different between the two groups (p > 0.05). We have found that GSTP1 isoenzyme was elevated in nasal polyp tissue compared to the control. The increase in protein expression of GSTP1 might have occured as a tissue response to the increased oxidative stress thus suggesting a role of GSTP1 in polyp formation.