MMP9 and nonpapillary renal cell carcinoma: However, a positive-value β coefficient (33.6) and lack of significance by the Cox PH model (p-value = 0.41, RR = 0.5) precluded us from clarifying its association with ccRCC progression, for which reason we focused on IKBKB, MMP9, PSMB9, and SOD2.