Immunodetection of bone marrow micrometastases in breast carcinoma patients and its correlation with primary tumour prognostic features

Methods such as immunohistochemistry that have enhanced the detection of carcinoma cells in bone marrow aspirates appear to be useful in identifying patients with aggressive tumours. To detect epithelial cells in bone marrow aspirates from breast carcinoma patients, we used a pool of five different monoclonal antibodies (MAbs), which recognise 100% of breast carcinomas, together with the alkaline phosphatase method on cytospun cells obtained from sternum and iliac crest. Primary tumours were also analysed for the expression of the c-erbB-1 and c-erbB-2 oncogene products, and of two differentiation-related markers and laminin receptors. Immunoreactive cells were detected in the bone marrow of 62 of the 197 patients tested (31%) without any correlation with clinical parameters such as tumour size or lymph node metastasis, whereas a significant (P < 0.01) correlation was found with enhanced monomeric laminin receptor expression in the primary tumour. In fact, this receptor was expressed in respectively 63% and 38% of primary tumours from patients with and without immunoreactive cells in the bone marrow aspirates. Thus, the presence of immunoreactive cells in bone marrow correlates with the expression in the primary tumour of a marker of the metastatic potential of the tumour, the 67 kDa laminin receptor.