The B-cell lymphoma (Bcl-2) gene is highly expressed in CD34 positive (CD34+) T-cell progenitors and gradually decreased during differentiation with the lowest value, also for the protein, in CD4+CD8+ Double Positive (DP) T-cells [23], which are included, according to the immunologic classification of T-ALL, in the third subgroup, which contains cortical T-cells. This evidence concerns the gene CD34 and acute lymphoblastic leukemia.