It is well known that viruses are obligatory parasites that infect cells for replication. The interferon pathway is activated in the infected cells to produce signals for non-infected cells to protect them from the infection. Cancer cells have shown to have a defect in the interferon pathway, making them vulnerable to virus infection and replication. This can also be utilized as the main concept of smart targeting for naturally occurring oncolytic viruses as well as many other mechanisms.

Recombinant oncolytic viruses were created to increase both selectivity and killing effect. Further evidence from preclinical experiments showed that oncolytic viruses work synergistically with conventional cancer therapeutics which then made way for many clinical trials. Many RNA and DNA viruses were tested in preclinical studies for their oncolytic activity and found to be promising. All these results have driven attention to oncolytic virotherapy as the future therapy for cancer as it is defined as smart therapy due to it being selective, effective, and safe.

In this Special Issue, we are seeking to highlight the advances in the field of oncolytic virotherapy by using viruses as cancer therapeutics. A special platform can help researchers exchange knowledge and have more impact. We welcome the submissions of original research and review articles.

Potential topics include but are not limited to the following:

• Improving classical cancer therapeutics through combination with virotherapy
• Enhancing virotherapy through nanotechnology
• Increasing the killing efficiency of viruses through arming with new inserts
• Recombinant viruses for cancer targeting
• Using viruses for cancer imaging
• Immunotherapy by oncolytic viruses
• In-vitro new models for testing the efficacy of oncolytic viruses