Minimal Residual Disease in Breast Cancer

Overview

The incidence of breast cancer continuously increases in developed countries. The introduction of screeningmethods such as mammography or ultrasound lead to higher proportion of early diagnosed tumors. However, evenin early stage tumors occult neoplastic cells can spread to the organism. Such tumor cells are very likely precursorsof distant metastases. Using several monoclonal antibodies against epithelial mucins or cytokeratins on the cellsurface could be detected one tumor cell among 10 5 or 10 6 of normal bone marrow cells. These cells are not detectableby routine histopathologic exam. More sensitive but also more costly and technically demanding are PCR assays.The sensitivity might reach almost 1:10 7. Prospective clinical trials using immunocytochemistry have shown thatthe presence of stained cells in bone marrow is clearly associated with shorter disease free survival and overallsurvival. In the near future we may use the bone marrow examination for the presence of occult tumor cells in orderto improve current staging system or as a surrogate marker in the decision-making in regard to adjuvant systemictherapy or in the assessment of efficacy of adjuvant treatment. The review summarizes contemporary knowledgeassembled in preclinical and clinical studies.

Key words:
breast cancer, bone marrow, cytokeratin, mammaglobin, minimal residual disease.