Expression P glycoprotein and multidrug resistance associated protein in gastric cancer and its significance

Aim:To study the expression and significance of P glycoprotein(Pgp) and multidrug resistance associated protein(MRP) in gastric cancer. Methods:Streptavidin biotin peroxidase complex(SABC) methods, monoclonal antibodies against Pgp and MRP were employed. Results: Immunoreactivities were detected in 22 and 13 out of 43 cases of gastric carcinomas for MRP and Pgp respectively. Seventeen and 8 out of 43 cases were positive for MRP and Pgp in pericancerous tissues respectively. There were 5 and 9 out of 30 cases positive for Pgp and MRP respectively in chronic gastritis. Those were 4 out of 43 cases, 1 out of 43 cases, 0 out of 30 cases positive for both Pgp and MRP in tissues of cancers, pericancerous tissues and tissues of gastritis respectively. The ratio of positive cases was significant higher in cancers showing lymphatic or hematogenous metastasis than those showing no metastasis. Neither Pgp nor MRP was correlated with ages, sex, pathologic patterns of patients. Conclusion: Positive expression of MRP and Pgp are both high in gastric cancers; positive expression of Pgp is believed to be correlated with bad prognosis.