Propionate reduces insulin resistance (a risk factor for CRC; each 10 μU/mL decrease in insulin level reduces CRC risk by 8%) by regulating hepatic glucose metabolism (inhibiting the gluconeogenic enzyme Phosphoenolpyruvate Carboxykinase), but its genetic regulatory effect is weak (R2 = 0.08 for propionate synthesis PGS vs. 0.12 for butyrate), which may be related to differences in metabolic pathways (propionate is mainly metabolized in the liver, while butyrate is metabolized locally in the colon). The gene discussed is INS; the disease is colorectal carcinoma.