The 2016 revision of WHO classification added a provisional entity called Early T-cell precursor (ETP) ALL. This subset is characterized by a unique immunophenotypic (reduced expression of T-cell markers, CD1a, CD8, and CD5) and genetic profile, indicating only limited early T-cell differentiation, with retention of some myeloid and stem cell characteristics (2). This evidence concerns the gene CD5 and acute lymphoblastic leukemia.