FISH analysis of CECs in patients with MM. Multicolour FISH analysis of immunomagnetically sorted CECs by means of Dynabeads shows 1 CEC (bottom left) with a 13q14 deletion (1 red signal, bottom left arrow) and a normal diploid copy number of chromosome 10 (2 green signals), and 1 cytogenetically normal CEC (top right) with 2 red (top 2 arrows) and 2 green signals. In patients with MM, most CECs are EPCs because they express CD133, a marker gradually lost during EC differentiation (positive red staining for PE-conjugated murine anti-CD133 monoclonal antibody). Note that several Dynabeads are attached to the cells. Scale bar equals 10 μm.