Serum CA199 levels are significantly increased in patients suffering from liver, lung, and other diseases

CA199 is a sialic acid containing glycan antigen found in both glycoproteins and glycolipids, which is recognized by monoclonal antibodies generated by hybridoma technology. The increased serum CA199 levels measured by using the monoclonal antibodies have been used as diagnostic or prognostic biomarker for pancreatic cancer. Even though increased serum CA199 levels are also observed in other cancers and noncancer diseases, it is largely unknown if CA199 levels could serve as biomarkers for other diseases as well. Therefore, in our current study, serum CA199 levels from 45,645 patients with 47 clinically defined diseases and 14,783 healthy controls who attended their annual physical examination were collected and measured by the clinical laboratory in the Affiliated Hospital of Qingdao University over the past 5 years. Based on the median, mean, and − Log10 p values, we found that patients with pancreatic cancer, lung fibrosis, cirrhosis, liver cancer, hepatitis, and pancreatitis had the highest media and mean serum CA199 levels with statistical significance based on the − Log10 p values. Unexpectedly, patients suffering from gout and anemia had significantly low CA199 levels compared to that of the healthy controls. These results showed that serum CA199 levels are not only increased in pancreatic and other cancer patients but also either increased or decreased in noncancer diseases. The overall data indicated that the abnormal serum CA199 level might be an indicator of system malfunction rather than a cancer biomarker in general.