A high JAK2(V617F) allele burden was correlated with the transformation to myelofibrosis (p<0.0001), but not with the transformation to acute leukemia.
JAK2 V617F mutation was detected after transformation to CMML in 1 of them; in the other, a novel translocation t(5;12)(p13;q24) was observed at the time of progression to acute leukemia.