3-Phosphoserine and carcinoembryonic antigen (CEA) in combination can attain a higher accuracy of detection in gastric cancer, plays an inhibitory role against colorectal cancer by inhibiting CDK activity, and cholesterol sulfate was identified as an oncometabolite.56,57 In addition, we discovered some less studied metabolites, such as 1-mristoyl-sn-glycero-3-phosphocholine, 16b-hydroxyestradiol, d-lyxose, dioctyl phthalate, dl-lactate, Leu-Phe in SCLC, all of which contributed to our diagnostic model for identifying SCLC. The gene discussed is CEACAM5; the disease is gastric cancer.