Both ATF4 and its binding partner CEBPB (Ameri and Harris, 2008; Vinson et al., 1993) were upregulated in arginine-starved THP1 cells (Figure 2B), and ATF4 is upregulated in primary blasts from ASS1-expressing AML patients (Figure 2C). The gene discussed is CEBPB; the disease is acute myeloid leukemia.