FASN and nonpapillary renal cell carcinoma: Lipid droplet and cholesterol ester accumulation are hallmarks of ccRCC, and tumor cells express critical enzymes driving lipogenesis, including fatty acid synthase (FASN), unsaturated fatty acid synthase (SCD), and long-chain lipoacyl-CoA synthase (ACSL) (Deng et al. 2025; Klasson et al., 2022; Li et al., 2023).