CTHRC1 and nonpapillary renal cell carcinoma: To further investigate the biological function of CTHRC1 in ccRCC, its expression was examined in five ccRCC cell lines (Caki-1, A498, OSRC2, 786-O, and 769-P) and one normal kidney cell line (HK2) using reverse transcription quantitative PCR assays (Fig. 1E) and western blotting analysis (Fig. 1F).