Depiction of 3 distinct categories of patients with T-ALL. The 3 categories include those with IL-7Rp mutations with constitutive pathway activation (“mutants”), those with IL-7R expression with ectopic IL-7Rp activation (“expressers”), and those with silenced IL-7Rp signaling (“nonexpressers”). “Mutant” and “expresser” groups constitute approximately 70% of patients with T-ALL and are characterized by activation of JAK/STAT signaling and reinforced BCL2 activation. Patients in these groups are predicted to be sensitive to the JAK inhibitor ruxolitinib and the BCL2 inhibitor venetoclax.