Could Oncolytic Viruses Provide a Breakthrough in Oncology?

Despite long-standing and large-scale studies on the nature of cancer and the development of numerous antitumor drugs, the incidence of cancer is growing and the five-year survival rate of cancer patients diagnosed at the advanced stages of the disease remains unacceptably low. The author considers the causes of such failures, which lie in the very nature of malignant cells: they can adapt to and resist practically any systemic therapeutic intervention. In this context, considerable hopes are pinned on oncolytic viruses, which are medical agents of a new type, able to produce an integrated effect on the disease. In addition to their direct ability to kill tumor cells selectively, oncolytic viruses stimulate natural processes of immune surveillance and removal of cancer cells. Besides, oncolytic viruses can kill tumor-initiating cancer stem cells that are highly resistant to chemo- and radiotherapy, and overcome the immunosuppression of the tumor microenvironment. These features make oncolytic viruses unique anticancer agents that combat cancer cells by multiple natural mechanisms. To incorporate viral cancer therapy into mainstream medical practice, it is necessary to intensify basic research on viral oncolysis mechanisms, to develop new therapeutic viral strains and tests for their personalized selection, and to improve methods of the local and systemic delivery of oncolytic viruses to tumor locations. Trials of drugs that would accelerate the introduction of new viral strains into medical practice will also require cardinal changes. Achievements in this sphere will help to overcome many old problems in the therapy of metastatic forms of malignant diseases.