Interestingly, six out of eight mice receiving GMPs co-transduced with BCR/ABL- and Myb-expressing viruses developed myeloid leukemia in six months after transplantation while mice transplanted with GMP cells that were singly transduced with either BCR/ABL or Myb expressing retrovirus remained healthy during the same period (Figure 5A). This evidence concerns the gene MYB and myeloid leukemia.