AFF1 and acute lymphoblastic leukemia: Aoki et al. reported that the CD34+CD38−CD19−CD33− bone marrow fraction of infant t(4;11) MLL-AF4 pro-B ALL patients contained normal haematopoietic stem and progenitor cells since they gave rise to normal myelopoiesis and lymphopoiesis in xenotransplantation [72].