Viruses and Cancer

There is a long history of using viruses to treat cancer beginning with anecdotal reports of temporary cancer remission after natural viral infections or viral vaccinations. The earliest report seems to be a 1912 account of the regression of cervical cancer in a patient vaccinated for rabies. Similar results were seen in cancer patients receiving small pox vaccinations, or following natural virus infections such as mumps or measles. Based on these reports as well as animal data, inoculations of live viruses into patients for cancer treatment were initiated in the late 1940s and early 1950s. The usual experience, however, was that after occasional temporary tumor regression, the tumor regrew and the patient died. These inoculations seldom resulted in long-lasting complete remissions. In 1957, Albert B. Sabin, M.D., who developed the live oral polio vaccine commented, “The most disappointing aspect is the fact that even when a virus is oncolytic and it punches a hole in a tumor, the immune response of the individual to the virus occurs so fast that the effects are quickly wiped out and the tumor continues to grow.” By 1970, interest in the direct action of viruses was fading and attention began to shift to using oncolysates, or viral-infected tumors, as vaccines. Influenza was one of the first viruses tested with sarcoma and malignant melanoma cells. Use of Newcastle disease virus, vaccinia, and vesicular stomatitis virus lysates for treating various tumors, followed. A phase III trial was completed in 1996 treating melanoma patients with vaccinia virus oncolysates from melanoma cell lines. Initial results showed an anti-tumor effect in a small subset of patients.