Most oncogenes identified in T-cell acute leukemia (T-ALL) encode factors either regulating stage-specific thymocyte development, comprising NOTCH1, LMO2 and HOXA genes, or ectopically activated factors, including TAL1 and NK-like homeobox genes (NKLs) [15]. This evidence concerns the gene NOTCH1 and T-cell acute lymphoblastic leukemia.