In the patients with oncocytoma, the MMP-2 values were positive in 3/4 (75%) of the specimens analyzed (range, 750–1,120 ng/ml; mean ± SD, 953±160 ng/ml), while in the patients with ccRCC, the values were positive in 12/16 (75%) of specimens (range, 697–1,949; mean ± SD, 1,027±314 ng/ml). The gene discussed is MMP2; the disease is nonpapillary renal cell carcinoma.