The Archdiocese of Chicago on Friday announced that Francis George, an American cardinal of the Catholic Church, will participate in a clinical research trial of a new cancer treatment drug, which is being conducted at the University of Chicago (UC) Medicine.

According to the Archdiocese, George was initially diagnosed with bladder cancer in 2006. In August of 2012, he learned that the disease has returned to his kidney and liver.

He recently underwent a regular medical procedure to replace a stent in his ureter. The procedure has been done routinely every six months over the last few years.

The form of cancer that struck George in 2006, called carcinoma in situ, was relatively unusual, accounting for about 10% of bladder cancer cases. The tumor was considered superficial - a flat growth limited to the wall of the bladder. But the cancer cells were of an aggressive type that could have spread rapidly to other parts of the body.

Doctors believed that the cancer won't spread so easily. However, patients suffering from bladder cancer are prone to developing cancer in kidney or liver. This will activate cells of the immune system, enabling them to attack cancer cells. This approach differs from traditional chemotherapy in which toxic drugs are used against cancer cells.

So far, this new drug's trial has shown good potential and promising results in patients who have the same type of cancer as Cardinal George.

Dr. Thomas Gajewski, leader of the immunology and cancer program at UCs' Comprehensive Cancer Center, said, "In a similar study unveiled in Chicago in June, about three in ten patients with advanced bladder cancer experienced tumor shrinkage when treated with an experimental drug".