FASN and neoplasm: Upregulation of FA in the plasma can be attributed to enhanced FA synthesis capacity in tumor cells, facilitated by abnormal expression and activity of FA synthesis-related enzymes such as fatty acid synthase (FASN), ATP-citrate lyase (ACLY), stearoyl-CoA desaturase (SCD1), and acetyl-CoA carboxylase (Lien et al., 2021).