Although previous studies have reported that mutations in FSIP2 are associated with morphological abnormalities of sperm flagella, progression of testicular germ cell tumors, and development of metastatic breast cancer 6,8,9, this is the first study to report the role of FSIP2 as a predictor of ccRCC prognosis. This evidence concerns the gene FSIP2 and nonpapillary renal cell carcinoma.