Could oncolytic viruses provide a breakthrough in oncology?

Abstract

Despite the long-term and intensive studies of the nature of cancer and the development of numerous anti-cancer drugs, the incidence of cancer is growing, and the five-year survival of cancer patients diagnosed at the advanced stages of the disease remains unacceptably low. The author examines the causes of the failures in cancer therapy, which are rooted in the very nature of malignant cells, as these cells can adapt and acquire resistance to almost any systemic therapy. In this regard, considerable hopes are associated with oncolytic viruses, which represent a distinct type of remedies capable of complex influences on the disease. In addition to their ability to directly kill cancer cells, oncolytic viruses can stimulate the natural processes of immune surveillance and elimination of cancer cells. Furthermore, oncolytic viruses can kill tumor-initiating cancer stem cells, that are highly resistant to chemo- and radiotherapy, and overcome the immune suppression of the tumor micro-environment. These features make oncolytic viruses unique anti-cancer agents that fight cancer cells by multiple natural mechanisms. To implement virus-mediated cancer therapy into broad medical practice the following are required: intensified studies on viral oncolysis are required and which would include a development of new advanced therapeutic viral strains; development of tests for predicting which virus strains from therapeutic panels are suitable for the patient; and, improvement of technologies for local and systemic delivery of oncolytic viruses to the tumor and metastases. Major changes would be also required in the practices of testing therapeutic drugs that accelerate the introduction of new viral strains into medical practice. Achievements in this direction help to overcome many old problems in the therapy of metastatic forms of malignant diseases.