Haidong Dong, M.D. Ph.D.

One reason cancer tumors are able to thrive and grow is because they can switch off parts of the body's immune system. The line of defense known to immunologists as T cells - can't do their job because the cancer has taken over the regulatory systems and, in essence, ordered them to stand down. Mayo researchers, such as Haidong Dong, M.D. Ph.D., believe they can re-start T cell immunity to fight back against the tumors.

Dr. Dong and his colleagues are trying to discover how the T cell's molecular switch actually works, how sets of T cells and tumor cells interact, and what is needed to help T cells grow, survive and function.

Eugene Kwon, M.D.

They believe one of the key regulators is the inhibitory molecule (called B7-H1) used by tumor cells that dampens the T cell activity through its receptors on immune cells. This suppressive feedback pathway has been identified and validated in animal models, and they found that blocking this pathway can improve tumor immunotherapy.

Eugene Kwon, M.D., is working the clinical end of this equation. By using tissues donated by Mayo cancer patients he has been able to correlate the existence of certain inhibitory proteins (such as B7-H1) in patients where cancer tumors had neutralized T cell activity. Thereby, not only validating the concept at another level, but identifying biomarkers that may be used to predict tumor growth.

The team is now collaborating with industry in attempt to confirm they have found a way to restart T cell immunity in humans.