Lene Juel Rasmussen is Professor at the University of Copenhagen and Managing Director of the interdisciplinary aging center, Center for Healthy Aging, residing within the faculty of Health and Medical Sciences. Her research aims to unravel the complex molecular basics of aging and the development of aging associated diseases. Within this context, her research group focuses on the molecular understanding of mitochondrial dysfunction and how cells achieve to preserve mitochondrial and nuclear DNA integrity as well as DNA repair. Mutations in DNA mismatch repair genes (MMR) predispose to inherited colorectal cancer Lynch syndrome/HNPCC. A particularly interesting repair component that her laboratory has identified is a novel MMR protein named the human exonuclease 1 (EXO1). The fact that this protein has now been recognized as a novel MMR gene proves that our approach to understand the basic molecular biology of DNA repair can have a significant impact in understanding the molecular pathology of human disease.