Carcinoma-associated antigens MK-1 and CEA in urological cancers

Background: The MK-I antigen, recognized by monoclonal antibody FU-MK-I, is widely associated with human carcinomas. However, the expression and distr ibution of MK-I in urological cancers is not well known. Materials and meth ods: We examined the expression of MK-1 in 10 urological tumor cell lines u sing flow cytometry and reverse transcription-polymerase chain reaction (RT -PCR) and in 15 cancel tissue specimens by immunohistochemical staining, an d then compared it with that of carcinoembryonic antigen (CEA). Results: Wh en analyzed by flow cytometry, MK-I was positive in 2 out of 3 bladder; 3 o ut of 3 prostate and one out of 4 renal tumor cell lines, whereas CEA was n egative in all the 10 tumor cell lines. RT-PCR confirmed the presence of MK -1 mRNA in all the six MK-l-positive tumor cell lines. Art immunohistochemi cal study demonstrated that MK-I was positive in 2 out of 5 bladder, 2 out of 5 prostate and one out of 5 renal cancer tissues. Again however, CEA was negative in all the 15 urological cancer tissues tested Conclusion: These findings suggest that MK-I seems to be a useful biological marker for malig nant urological tumors, especially in cases of bladder and prostate cancer.