MPIG6B and myelofibrosis: To confirm G6B as a potential marker of HSPCs derived from the malignant clone, G6B-positive and -negative cells were FACS-isolated from healthy donor and myelofibrosis patient MNCs and the expression of mutant versus wild-type JAK2 was determined by quantitative real-time PCR (Moliterno et al., 2006).