| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1998: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
A murine monoclonal antibody G250 (MAbG25O) raised against human renal cell carcinoma (RCC)(Oosterwijk, et al, 1986) has been known to react with a large proportion of RCC, but not with the norma1 kidney tissue. The antigen recognized by MAbG25O is present in the plasma membrane and expresses in several types of malignancies. Recently, G250 antigen gene has been isolated (Oosterwijk et al. 1995), and database analysis revealed that G250 antigen is identical to MN/CA IX originally deribed from Hela cell (Pastorek et al, 1994). To determine whether G250 antigen (MN/CA IX/G250) could be a potential therapeutic target and a tumor marker, a total of 147 cases of RCC were investigated immunohistochemically as well as, by reverse transcriptase polymerase chain reaction (RT-PCR) anilysis. In addition, total RNAs extracted from patients' peripheral blood samples were analyzed for MN/CA9/G250 mRNA signals. Immunohistochenistry resulted in strong expression in 128/147 (87.1%) of RCC, in contrast to the lack of expression observed in normal tissues. RT-PCR analyses of frozen specimens resulted in the clear detection of MN/CA9/G25OmRNA signals in 137/147 (93.2 %), and despite of the subtle differences, the results were almost identical to those for immunohistochemistry. Although high grade and stage tumors exhibited significaitly lower expression than low grade and stage tumors, a large proportion of tumors expressed MN/CA9 IX/G250 protein as well as mRNA.RT-PCR analysis of patients' blood samples revealed the presence of circulating MN/CA9/G25O expressing cells. These findings suggest that this antigen may be a potential therapeutic target as well as diagnostic marker for RCCs.
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