ATF4 has also been demonstrated to facilitate anti-neoplastic agent bortezomib‐induced upregulation of anti‐apoptotic myeloid cell leukemia-1 (Mcl-1) protein, which is an anti-apoptotic Bcl-2 family protein that plays essential roles in multiple myeloma survival and drug resistance in many tumor types (Figure 2) (Hu et al., 2012). This evidence concerns the gene MCL1 and neoplasm.