Circulating tumor cells: not all detected cells are bad and not all bad cells are detected.

摘要

More than 90% of cancer deaths result from the development of hematogenously disseminated metastasis. The presence of circulating tumor cells (CTCs) in patients with cancer was first reported in 1869. More recently, methods have been developed to detect, isolate, and characterize CTCs in multiple different malignancies that arise in solid organs. The most widely used method, designated CellSearch (Veridex, Raritan, NJ), relies on immuno-magnetic capture of CTCs using antibodies against the epithelial cell adhesion molecule (EpCam), which is expressed on the cell surface of many epithelial malignancies, followed by additional characterization with 4',6-diamidino-2-phenylindole staining (to demonstrate that the detected event is a nucleated cell), and by immu-nofluorescence analysis with antibodies against cytokeratin (to demonstrate it is epithelial) and CD45 (to demonstrate it is not a leukocyte). Numerous studies have shown that the presence of elevated CTC levels, as determined by CellSearch, is negatively correlated with prognosis in patients with metastatic cancers of the breast, prostate, and colon.