NUPR1 and nonpapillary renal cell carcinoma: To assess the effect of NUPR1 on ccRCC tumorigenicity in vivo, we established a xenograft mouse model in which Caki-2 cells transfected with shCtrl, shNUPR1-1 or shNUPR1-2 were inoculated subcutaneously into the dorsal regions of nude mice.