21 examined CEA in 70,993 patients with 49 types of diseases and found that the median CEA value was significantly different in 42 types of diseases versus healthy subjects, among them, in the descending order, pulmonary fibrosis, pancreatic cancer, uremia, COPD, colorectal carcinoma, Alzheimer’s disease and lung cancer. The gene discussed is CEACAM5; the disease is Alzheimer disease.