MMP9 and renal cell carcinoma: LDHC was abnormally expressed in 22.2% (4/18) RCC tissues, whereas no LDHC expression was found in adjacent tissues; a high percentage of RCC tissues (27/133) contained LDH-C4 protein; LDHC had a significant correlation with EMT, which could elevate the expression level of MMP-9 and enhance the migratory ability of RCC cells.