I recently ran across an article describing virotherapy.  Nicoletta Lanese, a Live Science contributor gave information on the early days of virotherapy and how it works.

Some of the viruses have a natural preference for attacking tumors and now the scientists are developing them into promising cancer treatments. This has been known for over a century but has only made advancements in genetic engineering to enable viruses to become a viable cancer therapy, with the hopes that this treatment will someday go viral.

Viruses prefer to attack the cancerous tissues rather than healthy ones so oncolytic virotherapy is taking advantage of this. It alerts the host immune system to a cancer’s presence in addition to killing off tumor cells. Dr. Antonio Chiocca, neurosurgeon-in-chief and chairman of the department of neurosurgery at Brigham and Women’s Hospital in Boston says our immune systems recognize pathogens well but have not evolved to recognize tumors very well.

Oncolytic viruses, or viruses that infect and kill cancer cells, can likely be used in the treatment of brain cancer. By placing a viral infection in the tumor it should alert and wake up the immune system to the fact there is a tumor there. Immunotherapy was being experimented with in the late 1800s. William Coley, a surgeon, became famous in the early 1900s for his attempts to fight cancer by exposing patients to extractions drawn from infected tissue. The vaccine was called Coley’s toxins and worked by inducing fever, chills and inflammation in the patient.  

In the 40s and 50s there was a resurgence of virotherapy research that was in a review in the journal Nature Biotechnology. Hundreds of cancer patients in clinical trials were exposed to the mumps, hepatitis and West Nile with results varying widely. In the 80s the modern era of oncolytic virotherapy appeared, and the field’s prospects are looking up.

Virotherapy has advanced significantly in the past few decades but research still remains difficult. Picking the right virus and deciding how to arm it and deliver it is the challenge, according to Grant McFadden, director of the Biodesign Center for Immunotherapy, Vaccines and Virotherapy at Arizona State University. Oncolytic viruses have the potential to morph into runaway viruses that adapt after administration or recombine with human pathogens already present in a patient then begin ferociously infecting healthy tissue.

While scientists continue searching for new and powerful oncolytic viruses, virotherapy seems destined to continue to expand.

Dr Fredda Branyon