Resistance proteins in human kidney, breast, ovarian and lung-carcinoma - a comparative-analysis.

The expression of P-glycoprotein (P-170), glutathione S-transferase-pi (GST-pi), dihydrofolate reductase (DHFR) and thymidylate synthase (TS) was analyzed immunohistochemically in human tumors of different origin. The resistance proteins were expressed at varying degree: all kidney carcinomas (n=25), 40 of 56 non-small cell lung carcinomas (NSCLC) (71%), 8 of 15 ovarian carcinomas (53%), 5 of 11 breast carcinomas (46%) and 3 of 14 small cell lung carcinomas (SCLC) (21%) expressed more than one resistance protein. A comparison of the immunohistochemical data with the clinical response rates as reported in literature, demonstrates an evident correlation between the number of resistance proteins and the clinical outcome.