We found that leukemia cell lines as well as clonogenic blasts isolated from primary chronic myelogenous leukemia (CML) and acute myelogenous leukemia (AML) patients express receptors for C3a and C5a on their cell surfaces and respond by chemotaxis and increased adhesion to stimulation by both ComC cleavage fragments [31]. This evidence concerns the gene C3 and chronic myelogenous leukemia, BCR-ABL1 positive.