Abstract

Cancer is a complex disease and is difficult to treat. Until the early twentieth century, it was treated by surgical removal which later on was combined with chemotherapy, radiotherapy and immunotherapy. However advances in molecular biology and genetics lead to the establishment of virotherapy. The geneticmodification of oncolytic viruses have improved their tumorspecificity, targeted delivery and increased efficacy, leading to thedevelopment of new weapons for the war against cancer especially in those cancer patients in which tumor is inoperable. In this review, we describe the basis of oncolyticvirotherapy and how the genetically modified tumor-specific viruses are developed. Utility of oncolytic virotherapy to treat cancer, clinical trials and their success rate are also discussed. We conclude with current and future challenges in oncolyticvirotherapy and the safety concerns raised by the trialsconducted so far.