Western blot analysis showed that inhibition of PKCδ by rottlerin (4 μM) markedly blocked ATRA-induced phosphorylation of eIF2α in HSCs, HL60 myeloblastic (AML-M2), and THP1 monocytic AML cells (AML-M5) (Figures 6(a)–6(c)). This evidence concerns the gene EIF2A and acute myeloid leukemia.