CA 15-3 and breast cancer

The monoclonal antibodies CA 15-3 were developed against the two antigens 115D8 of the human milk fat-globulin membrane and DF 3 of breast cancer. In a prospective study the new radioimmunoassay was determined pre- and postoperatively. Group I: breast cancer n = 63; G II: benign disease of the breast n = 52; G III: malignomes outside the breast n = 114; Group IV: benign surgical disease and health blood donors n = 288. Results: The normal value of the CA 15-3 being fixed below 25 u/ml, we ascertained in this study a sensitivity of CA 15-3 of 37% for mamma carcinoma, a specificity of 85% and a total accuracy of 80%. In the course of the follow-up treatment CA 15-3 and CEA were determined simultaneously in 392 patients who had been treated surgically because of breast cancer. The sensitivity rate in detecting metastases was 72% in CA 15-3 and 40% in CEA. The CA 15-3 RIA turned out to be not mammaspecific for screening, but it is definitely superior to CEA for the detection of metastases from breast cancer in the tumor follow-up treatment.