MTOR and leukemia: Canonically, ASNase efficacy is linked to the mTOR mediated block of protein synthesis, dependent on the absence of Asn-loaded tRNA which, in turn, depends on the inability of leukemia cells to produce ex novo Asn because of their phenotype deficient in Asparagine Synthetase (ASNS), the only enzyme capable of synthesizing Asn [37,38].