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

OBJECTIVE

To compare the levels of MN/CA9 expression with clinicopathological variables in renal cell carcinoma (RCC), and thus evaluate MN/CA9 expression 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-polymerase chain reaction (RT-PCR) analysis. In RCC, MN/CA9 expression was compared 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 MN/CA9 expression were significantly higher in tumours consisting only of clear 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 expression, and high MN/CA9 expression was associated with a good patient outcome.

CONCLUSION

These results suggest that MN/CA9 expression is a potential diagnostic biomarker of RCC, especially the clear-cell type, and can be targeted using molecular biological techniques.