Expression and significance of P-gp, LRP, MRP in gastric cancer

Objective To detect the expression of multidrug resistance proteins P-gp, LRP, MRP, and analyze the relationship between them and the clinicopathological factors. Methods The expression of P-gp,LRP, MRP in formalin-fixed paraffin-embedded tissue sections was determined by a labelled StreptavidinPeroxidase (SP) immunohistochemical technique, and the results were analyzed in correlation with clinicopathological data. None of these patients received chemotherapy prior to surgery. Results The positive rates of P-gp, LRP, MRP were 86.4 %, 84.7 % and 27.1%, respectively. The difference between the positive rate of P-gp and MRP was significant statistically, as well as the difference between the expression of MRP and LRP. No significant difference was observed between P-gp and LRP, but the positively correlation between the expression of P-gp and LRP was observed. No significant correlation between the expression of P-gp, LRP, MRP and the grade of differentiation were observed. The expression of P-gp was correlated with clinical stages positively (r=0.742), but the difference with the expression of P-gp in different stages was not significant. Conclusion The expression of P-gp, LRP, MRP in patients with gastric cancer without prior chemotherapy are high and indicates that innate drug resistance may exist in gastric cancer. Key words: Gastric neoplasms;  P-glycoprotein;  Multidrug resistance-associated protein;  Lung resistance protein;  Chemotherapy