Pulmonary extramedullary hematopoiesis in patients with myelofibrosis undergoing allogeneic stem cell transplantation.

was not generated in this three-way translocation. Translocation t(8;18;16)(p11;q21;p13), another three-way translocation variant of t(8;16)(p11;p13) found in a 15month-old boy with AML M5b, also has a structure that could not generate CBP-MOZ but MOZ-CBP, while RTPCR was not performed in this case. Moreover, Murati et al. reported a 72-year-old man with AML M5a having a complex t(8;16)(p11;p13), in whom only MOZ-CBP but not CBP-MOZ was detected as expected because of the insertion of 8q material between 16p and 8p on the der(16). These results clearly show that the CBP-MOZ fusion transcripts are not essential for the development of AML with t(8;16)(p11;p13) and its variants. We find for the first time that MOZ-CBP fusion transcripts are expressed in a case of infant leukemia with a variant of t(8;16)(p11;p13), and the fusion transcripts were shown to be two novel variants. Although predicted MOZCBP fusion proteins lack a protein interaction domain, C/H1 (cysteine/histidine-rich domain 1), compared to previously reported ones, these fusion proteins retain most of the other functional domains of CBP, including the bromodomain and the HAT domain (Figure 2c) which were reported to be important for MOZ-CBP to inhibit the Runx1-mediated transcription and myeloid cell differentiation. This suggests that the novel MOZ-CBP proteins are also leukemogenic and contribute to leukemic development in this case. While the reason for the favorable outcome of infant leukemia with t(8;16)(p11;p13) is not clear, secondary mutations may be required to develop aggressive disease as observed in adult patients. The difference of MOZ-CBP structures between infant and adult patients might also be related to the different outcomes. To clarify these questions, more cases of both infant and adult AML with t(8;16)(p11;p13) need to be analyzed.