The research examined the levels of an immunosuppressive protein called CD200 in kidney cancer patient tissue, to determine its effects on the body’s natural anti-cancer immune responses. CD200 is cut from the cell surface by an enzyme to create a functionally active soluble form known as sCD200, however it is unknown which enzymes are responsible for this.
CD200 is overexpressed in kidney cancer compared to normal tissue. High CD200 levels were found to significantly alter the anti-cancer immune response, including by protecting tumour cells from being killed by Natural Killer (NK) cells. Gemma found that an enzyme called ADAM9 could be partly responsible for the cleavage of CD200 from the cell surface. The research also showed that sCD200 is still able to protect tumour cells from NK cell killing, even after cleavage from the cell surface.
CD200 is able to suppress normal anti-cancer immune responses, therefore anti-CD200 drugs may have some benefits for kidney cancer patients by reinvigorating their immune systems to fight off cancer cells.
The levels of sCD200 in patient urine or blood could be used to diagnose kidney cancer in its early stages.