[15 years CA-125 antigen: usefulness and limits. Apropos of 3 clinical cases]

Fifteen years ago, the first clinical assay of the serum tumour marker CA 125 was introduced as a commercial kit. This test is currently the most widely used tumour marker in gynaecologic oncology. Studies have shown that the CA 125 is a valuable tool in the follow-up management of ovarian cancer. As a teaching exercise we present the analysis of three clinical cases, in which CA 125 was determined. Two of these patients did not have an ovarian cancer. It appears that this tumour marker very often is not only used in the follow-up of ovarian cancer, but also as a screening test and as a diagnostic tool. This inappropriate use (due to the lack of specificity and therefore many false positive results) can be avoided by considering it's limits.