SIRT4 and nonpapillary renal cell carcinoma: Our results based on the clinical-pathological characteristics of patients with ccRCC showed that the expression of SIRT2, SIRT3, SIRT6, and SIRT7 was increased in tumor-stage 1-4 subgroups, SIRT1 was increased in tumor-stage 1, and the expression of SIRT4 and SIRT5was decreased.