Isolated breast cancer cell and micrometastasis in sentinel lymph node. (a) Individual isolated tumour cell (→) and (b) small micrometastatic group of tumour cells (→) in the sentinel lymph node of two different breast cancer patients, as detected with anticytokeratin (AE1/AE3) antibodies (400×). The clinical relevance of (a) versus (b) is at present unclear.
Chambers et al. Breast Cancer Res 2000 2:400-407 doi:10.1186/bcr86