Lactate, a significant carbon source utilized for lipid synthesis, plays a crucial role in the promotion of MUFA production and the inhibition of ACSL4 through the hydroxycarboxylic acid receptor 1 (HCAR1)/ monocarboxylate transporter 1 (MCT1)- sterol regulatory element binding protein 1 (SREBP1)- stearyl coA desaturase 1 (SCD1) pathway, thereby inhibiting the ferroptosis in tumor cells. The gene discussed is ACSL4; the disease is neoplasm.