Viral cancer therapy

In spite of the advances achieved in cancer therapeutics, conventional ther apies still face problems such as toxicity to normal tissues and low effica cy in advanced phases of the disease. One of the most recent options, albei t experimental, is gene therapy. This strategy shows higher specificity tha n conventional therapies, but the low efficiency of gene transduction is a hurdle yet to be overcome, and the clinical trials have not shown the expec ted efficacy. Recently, oncolytic viruses have revived as an alternative in the field of cancer therapeutics. By virtue of the advances in virology an d molecular biology techniques, the manipulation of viral genomes to attenu ate their pathogenicity and the modification of their life cycle to allow t umor specific viral replication are now possible. At the moment, adenovirus and herpes simplex type I mutants are the most commonly employed viruses. Recent clinical trials using these mutant viruses have shown safety and eff icacy. Moreover, viral therapy has been combined with radiotherapy or chemo therapy demonstrating additive antineoplastic effects. In this manuscript, we review the biology behind this therapy, the obstacles, and the ongoing c linical trials.