BCR and chronic myelogenous leukemia, BCR-ABL1 positive: BCR-PDGFRα fusions: several authors reported that, unlike the common BCR-ABL1 chimeric gene found in CML [62,63], the BCR-PDGFRα fusion detected in HES associates with different hematological diseases, such as atypical CML and pre-B ALL [64,65,66].