Expression of multidrug resistance-related markers in gastric cancer

Background: To detect the expression of glutathione S-transferase Pi(GST-pi ), multidrug resistance-associated protein (MRP), lung-resistance protein(L RP), multidrug resistance gene1 (MDR1) and MGr1 antigen(MGr1-Ag) in the pat ients with primary gastric cancer and without any prior chemotherapy and to evaluate the correlations between them. Patients and Methods: The expressi on of GST-pi MRP, LRP and MDR1 in cancer tissue and the adjacent non-cancer ous tissue from 50 patients was examined by semiquantitative reverse transc ription-polymerase chain reaction (RT-PCR). The expression of MGr1-Ag in th ese tissues was also examined by immunohistochemistry. Results: The positiv e rate of GST-pi mRNA, MRP mRNA, LRP mRNA, MDR1mRNA and MGr1-Ag in gastric cancer tissue was 36.00%, 12.00%, 10.00% 10.00% and 18.00% respectively The overall positive rate of their expression was 58.00%. Clinicopathological factors were not significantly related to their expression. No significant correlation was observed between these markers. Conclusion: These MDR marke rs are differently over-expressed and no coexpression exists in gastric can cer. MGr1-Ag was a novel MDR protein.