The expression of G250/MN/CA9 antigen by flow cytometry: Its possible implication for detection of micrometastatic renal cancer cells

Monoclonal antibody (mAb) G250 is a well characterized and specific mAb to renal cell carcinoma (RCC), The gene G250 was recently cloned and was prove d to be homologous to MN/CA9, The G250/MN/CA9 antigen was recently explored as a potential marker for RCC, Flow cytometry (FCM) allows quantitative an alysis of cells. The present study describes a flow cytometric method to de tect this antigen in human cell lines and in malignant and normal renal tis sues. Twelve human carcinoma cell lines (HeLa, Colo205, HT29, BxPC3, OVCAR3 , SKOV3, ACHN, A704, CAKI-2, SKRC-59, SKRC-10, and SKRC-52), 10 specimens o f normal peripheral blood mononuclear cells, and 38 malignant and 36 adjace nt normal renal tissues were studied. The malignant and normal renal tissue s were disaggregated mechanically into a single-cell suspension, stained by mAb G250, and analyzed by FCM, All 22 of the clear cell carcinomas, 6 of 8 mixed cell carcinomas, and 3 of 6 granular cell carcinomas were positive f or G250/MN/CA9 antigen. SKRC-52 and SKRC-10 were strongly positive for G250 /MN/CA9. The G250/MN/CA9 antigen could also be detected in HeLa, SKOV3, HT2 9, and A704 cells. One chromophobic, one chromophilic cell carcinoma, the n ormal renal tissues, and normal peripheral blood mononuclear cells were con sidered as negative. Our results further confirmed that the G250/MN/CA9 ant igen was an ideal marker for RCC, especially for clear cell carcinomas, and that this antigen was present in several types of malignant cells. FCM may serve as a fast tool of immunocytochemical detection of renal cancer cells . Flow cytometric detection of renal cancer cells by using mAb G250 should be further explored.