CEBPA and acute promyelocytic leukemia: As shown in Figure 5A, ATRA upregulated C/EBPα, C/EBPβ, and C/EBPε, whereas simultaneous knockdown of C/EBPα and C/EBPβ reduces ATRA-induced upregulation of C/EBPε, suggesting that C/EBPα and C/EBPβ are upstream regulators during APL cell differentiation.