We hypothesize that BRCA1- and BRCA2-mediated pancreatic ductal adenocarcinoma progresses through the PanIN route, as seen in both BRCA1 and BRCA2 murine models of pancreatic cancer. We further hypothesize that BRCA1 mutations may enable an additional pre- neoplastic pathway through MCN, and that IPMN may embody yet another pre- neoplastic pathway.