BACKGROUND: The MK-1 antigen, recognized by monoclonal antibody FU-MK-1, is widely associated with human carcinomas. However, the expression and distribution of MK-1 in urological cancers is not well known. MATERIALS AND METHODS: We examined the expression of MK-1 in 10 urological tumor cell lines using flow cytometry and reverse transcription-polymerase chain reaction (RT-PCR) and in 15 cancer tissue specimens by immunohistochemical staining, and then compared it with that of carcinoembryonic antigen (CEA). RESULTS: When analyzed by flow cytometry, MK-1 was positive in 2 out of 3 bladder, 3 out of 3 prostate and one out of 4 renal tumor cell lines, whereas CEA was negative in all the 10 tumor cell lines. RT-PCR confirmed the presence of MK-1 mRNA in all the six MK-1-positive tumor cell lines. An immunohistochemical study demonstrated that MK-1 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-1 seems to be a useful biological marker for malignant urological tumors, especially in cases of bladder and prostate cancer.
BACKGROUND: The MK-1 antigen, recognized by monoclonal antibody FU-MK-1, is widely associated with humancarcinomas. However, the expression and distribution of MK-1 in urological cancers is not well known. MATERIALS AND METHODS: We examined the expression of MK-1 in 10 urological tumor cell lines using flow cytometry and reverse transcription-polymerase chain reaction (RT-PCR) and in 15 cancer tissue specimens by immunohistochemical staining, and then compared it with that of carcinoembryonic antigen (CEA). RESULTS: When analyzed by flow cytometry, MK-1 was positive in 2 out of 3 bladder, 3 out of 3 prostate and one out of 4 renal tumor cell lines, whereas CEA was negative in all the 10 tumor cell lines. RT-PCR confirmed the presence of MK-1 mRNA in all the six MK-1-positive tumor cell lines. An immunohistochemical study demonstrated that MK-1 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-1 seems to be a useful biological marker for malignant urological tumors, especially in cases of bladder and prostate cancer.