cancer antigen CA 19-9 (carbohydrate antigen 19-9) in serum

^[1]^[2]^[3]

Clinical significance

carbohydrate antigen expressed on a high-MW mucin
the epitope is recognized by antibody 1116NS-199
the epitope is sialylated lacto-N-fucopentose II
the molecule carrying the epitope is a mucin in the sera of cancer patients, but is a ganglioside in tumor cells
the antigen is related to the Lewis blood group substance
only Le(a-b+) or Le (a+b-) patients will be CA 19-9 positive
CA 19-5 & CA 50 are related to CA-19-9
- CA 19-9, CA 19-5 & CA 50 in serum are elevated in:
  - gastric carcinoma
  - pancreatic carcinoma
  - hepatocellular carcinoma
  - gallbladder cancer (not diagnostic)
  - cholestasis
- use of both CA 19-9 & CA 50 can improve sensitivity

↑ Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996, pg 1075-76
↑ Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 497
↑ Cancer Antigen-GI (CA 19-9) Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0080461.jsp