[Technical aspects of immunocytochemical detection of disseminated tumor cells in bone marrow]

Early and clinically occult hematogenous dissemination of tumour cells is considered a sign of systemic tumour progression, since recent data suggest that these cells are seminal precursors of subsequent distant metastasis. Single isolated tumour cells can be detected by means of immunocytochemical and molecular techniques at frequencies as low as 10(-5) to 10(-6) exploring different body compartments, such as bone marrow, peripheral blood and lymph nodes. This review summarises the currently available data on techniques that can be used to detect metastatic breast cancer cells in bone marrow and values their opportunities and limitations.