Tiny ROS Boost Enables T Cells to Fight Tumors, Study Finds

New research from OHSU and Cambridge shows cancer-fighting T cells rely on small amounts of reactive oxygen species (ROS) to attack tumors; tumors counter this by exporting PRDX1, an antioxidant that neutralizes ROS in the tumor microenvironment, dampening T cell activity. Deleting PRDX1 in cancer cells reduced tumor growth and, in some models, restored sensitivity to immune checkpoint therapies. Analyses of human tumors corroborate PRDX1 release, revealing a new redox checkpoint and suggesting therapies that block tumor antioxidants or protect ROS-dependent T cell function.