In most normal and cancer cell types investigated thus far, ASNS mRNA and protein expression is rapidly increased upon Asn deprivation, as a result of the transcriptional response to the AAR (see below) but, while the fast increase in mRNA occurs also in ALL cells (22), the increase in protein is severely delayed, suggesting the existence of an active translational silencing mechanism. This evidence concerns the gene ASNS and acute lymphoblastic leukemia.