Abt et al. [291] demonstrated that acute lymphoblastic leukemia cells (T-ALL) (Figure 6A, upper), differently from other immune lineages (such as B-lymphoblastic cells or acute myeloid leukemia cells) (Figure 6A, lower), were sensitive to PNP inhibition, with a loss of cell viability and the activation of the caspase cascade. This evidence concerns the gene PNP and acute lymphoblastic leukemia.