MMP8 and nonpapillary renal cell carcinoma: Specifically, MMP3, MMP7, MMP8, MMP9, MMP12, MMP13, MMP17, MMP19, MMP20, and MMP23B were identified as independent risk factors for ccRCC, while MMP15 and MMP24 were identified as independent protective factors for ccRCC (Supplementary Fig. 1B,C).