Feed A Cold, Starve A Tumor

It has afflicted human beings since the beginning of time, but now researchers say the common cold virus could help them fight a bigger plague: cancer.

Research presented at a medical conference Monday suggests that genetically altered cold viruses have the potential to kill cancer cells without harming healthy cells the way chemotherapy does.

"We're using a live virus to directly target and kill cancer," explained Dr. Daniel Sze of the Stanford Medical Center.

CBS News Medical Correspondent Elizabeth Kaledin reports in trials involving 35 patients whose colon cancer had spread to the liver, a genetically engineered cold virus was injected into the body and was able to recognize and destroy only the cancerous cells while leaving healthy cells unaffected.

Dr. Sze says in many cases the tumors shrank and life was prolonged.

"After 7 months you can see the tumors have almost disappeared," he said.

Cancer specialists say the results, though preliminary, throw open the window on a brand new field.

"These are the first steps that show us we can use these viruses safely," said Dr. Yuman Fong from Memorial Sloan Kettering Cancer Center.

The use of viruses to fight cancer was discovered accidentally about a hundred years ago when scientists noticed that tumors shrank in patients given the rabies vaccine. Today, in addition to the common cold, researchers are trying to harness the power of several other viruses.

Dr. Fong is leading research into whether the herpes virus can also kill cancer cells. He believes herpes might be a better candidate because the body has such an effective immune response to the common cold.

But overall he believes the whole field has great promise.

"One of these viruses may very well change how we treat cancer," he said.

Which one and when will continue to be the focus of much intense research.