ASNS and cancer: Researches, using multi-step selected human cancer cell lines resistant to ASNase, have demonstrated that many adaptive changes occur in ASNase-resistant cells, including: 1) an increase in AsnS mRNA and protein expression; 2) a decrease in Asn efflux through Na+-independent exchange system; 3) a production of aspartic acid, the substrate for Asn synthesis by AsnS, via transamination; 4) a higher Gln synthetase (GlnS) activity through post-transcriptional regulation; 5) an activation of the Gln transporter9, 10, 11, 16, 17, 18.