When Failure Is Worse Than Giving Up: The Case of CTL.

Although much emphasis is given to the use of immune checkpoint inhibitors to restore the functionality of exhausted lymphocytes, very little is known about the fate of cancer cells that escape from the cytotoxic activity of T cells. In a previous issue of Cancer Research, Stein and colleagues investigated the response of cancer cells to CD8+ T cells disarmed of their killing activity. Spared cancer cells acquired stem cell-like features and displayed an enhanced capacity to form tumors and metastasize. These increased tumorigenic properties could represent the other side of the coin of T-cell surveillance seen in wound healing in which recognition of damaged tissue as "self" gives the green light for healing process.See related article by Stein and colleagues; Cancer Res 79(7):1507-19.