KIT and chronic myelogenous leukemia, BCR-ABL1 positive: These markers include the 2D7 antigen and the BB1 antigen, also known as basogranulin.48, 49 In addition, immature BM basophils express KIT and tryptase.50 It has also been described that basophils in CML can be detected and enumerated by 2D7 or BB1 staining and that the numbers of 2D7+ and BB1+ cells (basophils) correlate with the phase of CML.48, 49 However, both antibodies may also react with immature eosinophils in the leukaemic BM (P. Valent and H.‐P.