Serum CEA levels in 49 different types of cancer and noncancer diseases

Carcinoembryonic antigen (CEA) was first identified as colon cancer antigen in 1965. The higher serum CEA level than that of healthy individuals led to its clinical application as a diagnostic biomarker for colorectal cancer. Subsequent molecular biology studies revealed that CEA are glycoproteins from a family of 32 genes and are normally expressed in various tissues. Indeed, serum CEA levels are not only increased in colorectal cancer but also increased in other types of cancers and noncancer diseases. However, a systematic comparison of the serum CEA levels in different diseases has not been reported. In current study, serum CEA levels from 70,993 patients with 49 clinically defined diseases were retrieved in the clinical laboratory of Affiliated Hospital of Qingdao University over the past 5 years. In addition, serum CEA levels from 39,650 individuals who attended their annual physical examination were used as healthy controls. Based on the mean, median, and –Log10 p values, we found that patients suffering from 42 diseases had significantly increased serum CEA levels than that of healthy controls. Moreover, patients with lung fibrosis, pancreatic cancer, uremia, chronic obstructive pulmonary disease, colon cancer, Alzheimer's disease, rectum cancer, and lung cancer had highest media levels of serum CEA in a descending order. Furthermore, healthy individuals older than 65 years old ranked 24th out of 49 in the media levels of serum CEA. In summary, the increased serum CEA levels are associated with aging, cancers, and noncancer diseases and the molecular mechanisms behind the increased serum CEA levels in the 42 unrelated diseases need to be investigated.