COL4A4 and nonpapillary renal cell carcinoma: We used LASSO Cox regression to examine data from the TCGA dataset to identify a 20-gene signature (ADAMTS2, ADAMTS4, ADAMTS8, COL15A1, COL4A4, COL4A6, DCN, GPC2, HMCN1, ITGA5, ITGAX, MEGF6, MMP21, MMP7, NELL1, NPNT, PXDN, SEMA3B, VCAN, and VWA1) in ccRCC patients.