To evaluate the utility of c-erbB-2, carcinoembryonic antigen (CEA) and CA 15.3 in the early diagnosis of recurrence, serial serum determinations of these antigens were performed in 200 patients (follow-up 1-4 years, mean 2.2 years) with primary breast cancer and no evidence of residual disease (NED) after radical treatment (radical mastectomy or simple mastectomy and radiotherapy). Here, CEACAM5 is linked to breast cancer.