In 1995, the Collaborative Group of the Americas on Inherited Colorectal Cancer (CGA-ICC) was established to improve understanding of the basic science of inherited colorectal cancer and the clinical management of affected families. The CGA focuses on families with rare forms of inherited colorectal cancer: familial adenomatous polyposis (FAP), MYH-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis, other hamartomatous polyposes, serrated polyposis, and hereditary nonpolyposis colorectal cancer (HNPCC)/Lynch syndrome.