EIF2AK2 and cancer: Moreover, PKR also regulates some tumour suppressors and protein kinases involved in cancer pathways such as the signal transducers and activators of transcription factors (STATs), activating transcription factors (ATFs), tumour suppressor p53 (Tp53), the phosphatase and tensin homologue tumour suppressor (PTEN), the mitogen-activated protein kinases (MAPKs), and the toll-like receptors (TLRs), among others [4,7,8,13].