Overexpression of peroxisome proliferator-activated receptor γ and retinoid X receptor α in gastric carcinomatous tissue

Abstract

OBJECTIVE: To investigate the expression of peroxisome proliferator-activated receptor γ (PPAR-γ) and retinoid X receptor α (RXR-α) in chronic gastritis, gastric mucosal dysplasia and gastric carcinoma and to identify any correlations between PPAR-γ and RXR-α expression in this progression sequence. METHODS: Immunohistochemical methods (avidin− biotin−peroxidase complex) were used to examine the expression of PPAR-γ and RXR-α in 53 patients with gastric carcinoma, 18 with gastric mucosal dysplasia and 30 with chronic atrophic gastritis. Thirty-one patients with chronic non-atrophic gastritis acted as controls. RESULTS: The positive rates of PPAR-γ and RXR-α in gastric carcinoma were 41.5 and 54.7%, 27.8 and 38.9% in gastric mucosal dysplasia, 10.0 and 20.0% in chronic atrophic gastritis, and 6.5 and 16.1% in chronic non-atrophic gastritis, respectively. The expression of PPAR-γ and RXR-α increased during the progression from chronic non-atrophic gastritis to chronic atrophic gastritis, then to gastric carcinoma. Compared with chronic gastritis, the expression of PPAR-γ and RXR-α in gastric mucosal dysplasia and gastric carcinoma was significantly increased (P 0.05). There was a positive correlation between the expression of PPAR-γ and RXR-α in gastric carcinoma (r= 0.54, P < 0.01). CONCLUSIONS: Overexpression of PPAR-γ and RXR-α protein is apparent in human gastric cancer. This might be an early event in carcinogenesis, and both PPAR-γ and RXR-α may play independent and/or synergistic roles in the progression of gastric carcinoma.