Using Virii to Kill Cancer

There's an interesting article about studies that are attempting to use modified cold, smallpox, or herpes virii to kill cancer cells. The one attempts to use a 1-2 punch to knock out the cancer. First, the modified virus kills most of the cancer cells. After that, the immune system is boosted to mop up the rest. Interesting idea, though it sounds like one of those "crazy enough it might work" ideas. Then again inoculations are based off of weakened virii, so maybe it's not so crazy.