CA 125

Ca-125 is a high molecular weight cell surface glycoprotein. This glycoprotein is recognised by the monoclonal antibody OC 125. 

Immunohistochemical expression

The antigen is expressed by

 

Ovarian adenocarcinoma

60/861

  
 

Papillary serous adenocarcinoma of the cervix uteri

9/123

  
 

Breast adenocarcinoma

21/1071

  

Colorectal adenocarcinoma

13/941

Pulmonary tumours

7/102
   

Diagnostic utility

Although there is considerable overlap in immunoreactivity, positivity for CA 125 and HAM56, along with negative or weak staining for CEA, tend to favour an ovarian rather than a colorectal site for an adenocarcinoma.

References

Diagnostic histopathology of tumors. Edited by CDM Fletcher. 2nd edition. Churchill Livingstone. Page 623.

1 Lagendijk, J. H., H. Mullink, et al. (1999). "Immunohistochemical differentiation between primary adenocarcinomas of the ovary and ovarian metastases of colonic and breast origin. Comparison between a statistical and an intuitive approach." J Clin Pathol 52(4): 283-90.

2 Nouwen EJ, Pollet DE, Eerdekens MW, et al. Immunohistochemical localization of placental alkaline phosphatase, carcinoembryonic antigen, and cancer antigen 125 in normal and neoplastic human lung. Cancer Res 1986; 46:866-76

3 Zhou C, Gilks CB, Hayes M, et al. Papillary serous carcinoma of the uterine cervix: a clinicopathologic study of 17 cases. Am J Surg Pathol 1998; 22:113-20

Davis HM, Zurawski VR, Jr., Bast RC, Jr., et al. Characterization of the CA 125 antigen associated with human epithelial ovarian carcinomas. Cancer Res 1986; 46:6143-8

Quirk JG, Jr., Brunson GL, Long CA, et al. CA 125 in tissues and amniotic fluid during pregnancy. Am J Obstet Gynecol 1988; 159:644-9

Fukazawa I, Inaba N, Ota Y, et al. Relation between serum levels of tissue polypeptide antigen (TPA) and cancer antigen 125 (CA125) and their immunohistochemical identification in benign and malignant gynecological disease. Arch Gynecol Obstet 1988; 243:41-50

 

 

©SMUHT/PW Bishop