[Studies on multidrug resistance associated protein in retinoblastoma]

To detect the expression of P-glycoprotein (P-gp), lung resistance associated protein (LRP) and multidrug resistance associated protein (MRP) in retinoblastoma (Rb), to analyze the relationship between the expression of multidrug resistant (MDR) markers with clinic-pathological factors, the correlations among these three markers, and to study the possible mechanism of multidrug resistance in Rb.

It was an experimental study. Seventy-five cases of Rb were studied with immunohistochemical methods using antibodies against P-gp, LRP and MRP. The relationship between their expression and the clinicopathological features of Rb, and the relationship between the expression of these three markers were investigated.

The positive expression rates of P-gp, LRP and MRP were 64.0%, 25.3%, 36.0% in Rb, respectively. The co-expression rates of P-gp and LRP, P-gp and MRP, LRP and MRP were 18.7%, 32.0%, 20.0%, respectively. All tested proteins showed significant correlation to the differentiation of the tumor (P = 0.006, 0.000, 0.000, respectively), but no correlation was found between the expression of these markers and the age or sex of the patients. Significant positive correlations were observed between P-gp and MRP expression (P = 0.001), and between LRP and MRP expression (P = 0.000).

The intrinsic multidrug resistance of Rb involves the combined effects of P-gp, LRP and MRP.