To determine if Rylaze-induced serine upregulation is mediated by the AAR pathway, we treated AML cell lines with Rylaze alone (0.1 μg/mL) or in combination with a small molecule inhibitor for GCN2 (GCN2-IN-1) and examined the effect on AAR pathway proteins and PHGDH expression, the enzyme that catalyzes the first step in the serine biosynthesis pathway. This evidence concerns the gene PHGDH and acute myeloid leukemia.