DNA (IMAGE) UT Southwestern Medical Center Caption A UT Southwestern study discovered the molecular mechanism by which tumors defective in DNA mismatch repair respond to immunotherapy. This illustration depicts how cells use a programmed mismatch repair deficiency-activated system (robot) to detect and eliminate tumors (yellow cells). Credit Illustration by Yipin Wu Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.