Description
Genetic studies have shown that human T-ALLs can be divided into subgroups that are characterized by unique gene expression signatures and relate to stages of T-cell differentiation at which the leukemic cells arrest. Each molecular subgroup has characteristic genetic abnormalities that cause aberrant activation of specific T-ALL transcription factor oncogenes, including LYL1/MEF2C, HOXA, TLX1, TLX3 and TAL1/LMO2. Notably, the recently described Early T-cell Precursor ALL (ETP-ALL) patients have leukemic cells that show an early block in T-cell differentiation and significantly overlap with LYL1-positive T-ALL and MEF2C-dysregulated immature T-ALL. We studied the gene expression profiles of 64 primary T-ALL samples and found a high BCL-2 expression in immature T-ALL patients compared to patients belonging to other subgroups.