MN/CA IX/G250 as a potential target for immunotherapy of renal cell carcinomas.
The monoclonal antibody G250 (mAbG250) raised against a human renal cell carcinoma (RCC) has been shown to react with a large number of RCCs. Recently, G250 antigen was isolated and found to be homologous to the MN/CA9 gene originally identified in HeLa cells. To determine whether G250 antigen (MN/CA IX/G250) could be a potential therapeutic target and a tumour marker, a total of 147 cases of RCC were investigated immunohistochemically as well as by reverse transcriptase polymerase chain reaction (RT-PCR) analysis. In addition, total RNAs extracted from patients' peripheral blood samples were analysed for MN/CA9/G250 mRNA signals. Immunohistochemistry demonstrated strong expression in 128/147 (87.1%) of RCCs, 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/G250 mRNA signals in 137/147 (93.2%), and despite subtle differences the results were almost identical to those for immunohistochemistry. Although high-grade and -stage tumours exhibited significantly lower expression than low-grade and -stage tumours, a large proportion of tumours expressed MN/G250 protein as well as mRNA. RT-PCR analysis of patients' blood samples revealed the presence of circulating MN/CA9/G250 expressing cells. These findings suggest that this antigen may be a potential therapeutic target as well as diagnostic marker for RCCs.
Uemura
H
H
Department of Urology, Nara Medical University, Kashihara, Japan.
Nakagawa
Y
Y
Yoshida
K
K
Saga
S
S
Yoshikawa
K
K
Hirao
Y
Y
Oosterwijk
E
E
D000951:Antigens, Neoplasm / Q000032:analysis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases; D002292:Carcinoma, Renal Cell / Q000737:chemistry* / Q000175:diagnosis; D006801:Humans; D007167:Immunotherapy; D007680:Kidney Neoplasms / Q000737:chemistry* / Q000175:diagnosis; D009363:Neoplasm Proteins / Q000032:analysis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; C089226:CA9 protein, human; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases