We were able to define a new molecular classification for the overall cohort of adult T-ALL based on the prognostic value of molecular subgroups into good risk (TLX1, NKX2-1, LMO1), intermediate risk (HOXA), and poor risk (LYL1/LMO2, TAL1/LMO, HOXA13, TLX3). This evidence concerns the gene TAL1 and acute lymphoblastic leukemia.