PPBP and acute megakaryoblastic leukemia: The second segment was specific of non-DS AMKL samples and included the two olfactive receptor genes OR10A5 and OR10A4. The only significantly under-expressed segment included the region on chromosome 4 (4q12-q21) highly enriched in MK-specific loci (PF4, PPBP, CXCL5 and CXCL3) as in the case of DS AMKL samples, and was extended to PF4V1 locus.