MMP9 and nonpapillary renal cell carcinoma: The results showed that the expression of G6PD, Cyclin E1 and MMP9 at both mRNA and protein expressions levels were elevated in human ccRCC tumors compared with adjacent normal tissues (Fig. 1A-I), indicating that highly expressed Cyclin E1 and MMP9 may be positively correlated with G6PD overexpression and synergistically involved in ccRCC tumorigenesis.