Specific cytogenetic abnormalities can be found in many people with AML ; the types of chromosomal abnormalities often have prognostic significance . The chromosomal translocations encode abnormal fusion proteins , usually transcription factors whose altered properties may cause the " differentiation arrest " . For example , in acute promyelocytic leukemia , the t ( 15 ; 17 ) translocation produce a PML @-@ RARα fusion protein which bind to the retinoic acid receptor element in the promoters of several myeloid @-@ specific genes and inhibit myeloid differentiation .