PSAT1 and Burkitt lymphoma: In Burkitt lymphoma primary cells, ATF4 is transcriptionally regulated by MYC and is inducing the overexpression of PHGDH and PSAT1. In these cells, SSP supports the production of the antioxidant glutathione (through glycine) and the methyl donor SAM (through the folate/methionine cycles), and is therefore beneficial in reducing oxidative stress and increasing global histone H3 and DNA methylation, including methylation of certain tumor suppressor genes (60).