AUP1 and nonpapillary renal cell carcinoma: However, the study acknowledges several limitations, including the small number of patients included and the presence of confounding factors related to the expression of other genes associated with the accumulation of lipid droplets in ccRCC, such as ancient ubiquitous protein 1 (AUP1) and acyl-CoA synthetase 3 (ASCL3) [37,38].