Cancer Antigen (CA) 125 – 002303

This immunoassay is intended for the in vitro quantitative determination of OC 125 reactive determinants in human serum and plasma.¹ The Elecsys CA 125 II assay is indicated for use as an aid in the detection of residual or recurrent ovarian carcinoma in patients who have undergone first-line therapy and would be considered for second-look procedures.¹ The Elecsys CA 125 II assay is further indicated for serial measurement of CA 125 to aid in the management of cancer patients.¹ CA 125 belongs to the family of hybridoma-defined tumor markers. The values measured are defined by the use of the monoclonal antibody (MAb) OC 125. The antigenic determinant CA 125 is located on a high-molecular weight glycoprotein (200-1000 kd) isolated from cell culture or serum. The antigenic determination CA 125 has a protein structure with associated carbohydrate side-chains.^2,3 These determinants are associated with a high-molecular weight glycoprotein in serum and plasma of women with primary epithelial invasive ovarian cancer (excluding those with cancer of low malignant potential).

CA 125 is found in a high percentage of nonmucinous ovarian tumors of epithelial origin⁴ and can be detected in serum.^5,6 It does not occur on the surface epithelium of normal ovaries (adult and fetal). Ovarian carcinoma accounts for about 20% of gynecologic tumors; the incidence is 15/100,000.⁷ CA 125 has been found in the amniotic fluid and in the coelomic epithelium; both of these tissues are of fetal origin. In tissues of adult origin, the presence of CA 125 has been demonstrated in the epithelium of the oviduct, in the endometrium, and in the endocervix