SPINK13 and nonpapillary renal cell carcinoma: The mRNA expression levels of COL1A1, COL1A2, COL6A3, PRRX1, POSTN, COL5A1, SPINK13, PDGFRL, CTHRC1, FGG, SCG5, and DCN were markedly upregulated in ccRCC tissues (p < 0.05) compared with those in non-tumor kidney tissues.