Like mTORC1, GCN2 is also an appealing target for cancer drugs, which is based on the rationale that in contrast to mTOR, GCN2 is nonessential in normal cells and animals but that malignant cells have exaggerated amino acid dependencies and therefore use the GCN2-ISR as an adaptive survival and metabolic defense mechanism (42, 43). The gene discussed is EIF2AK4; the disease is cancer.