Re: Micrometastatic Breast Cancer Cells in Bone Marrow at Primary Surgery: Prognostic Value in Comparison With Nodal Status

Extract

Early occult spread of tumor cells must be regarded as a major cause for the development of metastatic disease in patients with completely resected breast cancer. Immunocytochemical assays with monoclonal antibodies directed against epithelial differentiation antigens have allowed the detection of micrometastatic carcinoma cells in bone marrow. Most of the studies were performed with monoclonal antibodies either against cytokeratin (a major constituent of the cytoskeleton in epithelial cells) or against membranebound mucins (e.g., epithelial membrane antigen, human milk fat globule, and tumor-associated glycoprotein-12 [TAG12]).

Results from a recent study on more than 700 breast cancer patients (1) suggested that the presence of TAG12- positive cells in bone marrow, as detected with monoclonal antibody 2E11, could be used as an independent prognostic indicator of a clinical relapse (1). We were, therefore, interested in investigating in more detail the nature of the TAG12-positive cells. Thus, we analyzed bone marrow samples from 165 control patients without carcinoma with the use of monoclonal antibody 2E11 and simultaneously with the use of monoclonal antibody A45-B/B3 directed against a common epitope present on several cytokeratin peptides, including heterodimers of cytokeratin polypeptides 8 and 18 as well as 8 and 19 (2).