On Tech Nation Health, it’s the power of viruses – against cancer. Moira speaks with Dr. Harry Gruber, the President for Science and Innovation at Tocagen about their genetically engineered viruses. Their first, glioblastoma, has received breakthrough therapy designation from the FDA. Tocagen is also working on colorectal, breast, lung, pancreatic and renal cancers, as well as melanoma. Dr. Gruber explains how the virus works.