CCND1 and nonpapillary renal cell carcinoma: The survival time of ccRCC patients is closely associated with tumor grade (P < 0.001; Figure 5A), and previous studies have reported that the level of CCND1 is related to tumor grade in some cancers.15, 33, 34, 35 Therefore, using the median expression as the cutoff point, we tested the proportion of different tumor grades in the CCND1 low and high expression groups.