“…13,14 Despite the biological, molecular and clinical heterogeneity of leukemia, the occurrence of alterations is clear since the beginning of the hematopoietic differentiation program. However, while for acute and chronic myeloid leukemia a population of leukemic stem cells is responsible for their development and recurrence, 15,16 for lymphoblastic leukemias, their undifferentiated nature appears not to be phenotypic and may be related to the tumor microenvironment, 17,18 which contributes to the disease pathogenesis.…”