Cancer genetics and response to oncolytic virus treatment for ovarian cancer

Ovarian cancers (OCs) are often defined as poorly immunogenic tumors that have low response rates to current immunotherapies and frequently develop resistance to chemotherapies. Oncolytic viruses (OVs) are an emerging therapeutic approach that is favored due to its multifactorial mechanism of action; OVs aim to enhance immune cell recovery and infiltration into the tumor, in addition to assisting the immune system to identify and target evasive tumors. While many different OVs have been studied, this review focuses on the four that have been extensively tested in preclinical models and clinical trials with OC patients: vaccinia viruses, vesicular stomatitis virus, herpes simplex 1, and adenoviruses. We will first explore how these viruses have been developed, modified and tested as monotherapies in OCs, with limited success. The various combinatorial approaches involving OVs that are currently being investigated to improve the outcomes for OC patients will then be addressed. Attention will be given to how the genetics of OC cells may influence response to OVs and how that has led to genetic modifications of OVs that improve the cancer specificity and efficacy of these therapies.