MN/CA9 gene expression as a potential biomarker in renal cell carcinoma

Objective To compare the levels of MN/CA9 expression with clinicopathologic al variables in renal cell carcinoma (RCC), and thus evaluate MN/CA9 expres sion as a possible biomarker for RCC. Materials and methods The level of expression of MN/CA9 was evaluated in 76 surgically obtained tissue samples (49 from RCC, 22 from normal kidney and five from oncocytoma) using semiquantitative reverse transcription-polymer ase chain reaction (RT-PCR) analysis, In RCC, MN/CA9 expression was compare d with stage, grade and cell type. Results MN/CA9 was expressed in 42 of 49 (86%) RCC samples, but in only two of 22 (9%) normal kidney and none of five oncocytoma samples. Levels of A MN/CA9 expression were significantly higher in tumours consisting only of c lear cells than in those containing other cell types (P=0.0189), and MN/CA9 was expressed in 34 of 37 (92%) RCC samples consisting only of clear cells . Tumours of low clinical stage showed a striking increase in MN/CA9 expres sion, and high MN/CA9 expression was associated with a good patient outcome . Conclusion These results suggest that MN/CA9 expression is a potential diag nostic biomarker of RCC, especially the clear-cell type, and can be targete d using molecular biological techniques.