Patients with advanced cancers who have a complete response to immunotherapy in which their tumors disappear and the cancer becomes undetectable after treatment have more effective immune cells than most people, a study conducted in Denmark has discovered.
Scientists had believed that so-called killer T-cells only recognized a single target on cancer cells. The new research, published on Monday in Cell, shows that patients who have successfully cleared advanced solid tumors have a superior form of killer T-cells capable of recognizing and attacking multiple cancer-associated targets simultaneously.
The researchers studied 31 patients with late stage solid cancer who received tumor-infiltrating lymphocyte (TIL) therapy, in which immune cells are removed from a patient's tumor, grown in large numbers in a laboratory, and returned to the patient to help the immune system kill the cancer cells.
All of the cells given back to these patients were T-cells.
"By looking at the blood of people whose cancer had totally cleared after TIL therapy, we were able to track down the successful T-cells," study leader Andy Sewell of Cardiff University School of Medicine in Wales said in a statement.
Researchers tested those cells on a patient's own cancer, cancer from other patients and against other cancer types.
"A multipronged killer T-cell from a cancer survivor was shown to be substantially better at recognizing cancer than a normal anti-cancer killer T-cell," Sewell said.
"Importantly, we have seen large numbers of multipronged T-cells in the blood of cancer survivors. To date, we have not found such multipronged T-cells in people where cancer progresses," he said, adding that it is possible multipronged T-cells "might be associated with complete remission or cancer clearance."
Eventually, the researchers hope to engineer multipronged T-cells in their lab to see whether they can be used to treat cancers.
