ATF4 and neoplasm: The ability of IRF7 to promote PDL1 transcription may be not as potent as IRF1, and the effect of PD1/PDL1 reverse signaling on eIF2α/ATF4 activation with subsequent inhibition of IRF7 expression may result in a negative correlation between the protein levels of IRF7 and PDL1 in the tumor tissue of SCC.