In fact, cancer cells have peculiar characteristics able to strengthen viral replication [124]: (i) they oppose apoptosis causing indefinite proliferation [125]; (ii) they are lacking in cellular antiviral response pathways [126,127]; (iii) they create a hypoxic environment in which OVs can replicate [128,129,130]; (iv) they usually show an over-active RAS signalling pathway, which allows viruses such as reovirus and vaccinia virus to specifically replicate and lyse tumor cells, in which the PKR pathway is not active. The gene discussed is EIF2AK2; the disease is cancer.