Monoclonal antibodies for detection of occult carcinoma cells in bone marrow of breast cancer patients.

Metastases develop in 30% to 40% of patients with operable breast cancer. Investigators have reported on the detection of occult micrometastases in bone marrow using an antibody to epithelial membrane antigen (EMA) and have since reported prognostic significance for these antibody-detected cells. In this study, two anti-cytokeratin monoclonal antibodies (35 beta H11 and 34 beta E12) were used to examine bone marrow specimens from patients with breast cancer. The technique was first studied in a test system in which human or monkey bone marrow was seeded with MCF-7 cells, and was determined to be sensitive enough to detect fewer than one cancer cell in 10(4) hematopoietic cells. An immunoglucose oxidase method was used for patient specimen antibody localization and was found to be free of false-positive staining. Marrow specimens from 25 patients with breast cancer of various stages were examined. No correlation with disease stage was observed. We conclude that the technique is feasible, but prognostic import remains to be determined.