Serum markers for primary and recurrent breast cancer: BCM-EIA, CAM 26 and CAM 29

Three sandwich enzyme immunoassays were used to evaluate serum from 93 women: 20 normal, 20 with benign breast disease, 22 with primary and 31 with recurrent breast cancer. Using the three assays, breast cancer mucin enzyme immunoassay (BCM-EIA) carcinoma-associated mucin antigen (CAM) 26 and CAM 29, both singly and in combination, we were unable to establish meaningful cut-offs to differentiate between patients with or without breast cancer. The sensitivity and specificity for BCM-EIA were 90% and 40%, for CAM 26, 89% and 42%, and for CAM 29, 91% and 66%, respectively. Serial serum specimens from 29 patients with recurrent breast cancer were assayed. At recurrence, an increase of 25% or more in marker level over the previous value was found in 24/29 (83%) BCM results, 14/29 (48%) CAM 26 results and 12/29 (41%) CAM 29 results. Prior to clinical detection of recurrence, stepwise increases in BCM and CAM 26 marker levels were seen up to 299 days prior to clinical detection of recurrence. We conclude that these markers may help in the early detection of recurrent breast cancer.