Paul Brennan leads the Genomic Epidemiology branch at the International Agency for Research on Cancer (IARC). He leads several studies that combine genomics and large scale population based epidemiology to better understand causes of cancer, as well as the mechanisms underlying these causes. He has a particular focus on trying to understand causes of esophageal cancer (with a focus on high risk regions such as North East Iran and central China), as well as renal and pancreas cancer (in central Europe), and also causes behind the increasing incidence of colorectal cancer in young adults.