ATF4 and hepatocellular carcinoma: Although we were surprised to find that the acutely acrolein-induced lung cell death was not associated with a loss of lung tissue VEGF expression (Figure 1B), this fact is not unprecedented and supports our observation that acrolein induces ER stress; Pan et al. showed in hepatoma cells that ER stress (likely via ATF4) increases VEGF transcription [47], Roybal et al. showed increased VEGF transcription in ER stressed retinal pigmented epithelial cells [48] and Li et al. in tunicamycin-stressed retinal capillary endothelial cells [49].