BCR and chronic myelogenous leukemia, BCR-ABL1 positive: During the second year from the diagnostic of CML the patient was assessed monthly for hemograms and we observed a switch to polycythemic phenotype, with increasing in hematocrit and haemoglobin range, without signs of clonal evolution for CML: the BCR/ABL transcript level remain undetectable at 24 months, but it was detected JAK2V617F mutation in homozygous state (Fig. 3).