The ScreenCell Cyto device is devoted to all techniques of cytology: cytomorphology, immunocytology, and 2D or 3D FISH technics. The fixed cells retained on the membrane show a well-preserved morphology. The filters can be directly examined under the microscope after staining by a nucleo-cytoplasmic coloration like May-Grunwald-Giemsa or hematoxylin-eosin or Papanicolaou. The same filters can be discolored and handled for immunocytology, allowing a correlation with the cells morphologically identified. The cells are analyzed according to classical criteria of malignancy in order to distinguish normal leucocytes from atypical cells concordant with circulating tumor cells (CTCs). Furthermore, the ScreenCell technique makes it possible to identify clusters of CTCs as well as large atypical macrophages named CAMLs (Cancer-Associated Macrophage-Like) and platelets mixed with CTC clusters in microemboli.