TAL1 and acute lymphoblastic leukemia: In intricate T-ALL networks where both NOTCH and TAL1 deregulation can coexist, we find that while NOTCH patients are associated with a favourable prognosis, monoallelic, but not biallelic TAL1, expression tends to convert the clinical outcome towards more adverse prognosis in the Notch subgroup, and to further aggravate the bad prognosis of Notch1WT patients.