ATF4 and mantle cell lymphoma: Ishizawa et al. [13] found the effect of ONC201 in acute myeloid leukemia and mantle cell lymphoma cells was not dependent on either caspase-8 activation or Foxo3a-dependent transcription of TRAIL. Gene expression profiling analysis revealed that ONC201 induces endoplasmic reticulum (ER) stress or integrated stress response (ISR)-related genes, such as Activating Transcription Factor 4 (ATF4) and C/EBP-homologous protein (CHOP).