This classifier also performed better than the conventional biomarkers (including carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), carbohydrate antigens (CA125, CA15-3, CA19-9, and CA72-4), cytokeratin 19, and neuron-specific enolase (NSE)) and epidemiological risk factors (including indices of overweight, obesity, and alcohol consumption and previous history of cancer) when predicting colorectal cancer. The gene discussed is AFP; the disease is obesity due to melanocortin 4 receptor deficiency.