Tumour spectrum of non-polyposis colorectal cancer (Lynch syndrome) on the island of Tenerife and influence of insularity on the clinical manifestations.

Colorectal cancer is a complex disease from a genetic point of view because both genetic and environmental factors interact in its development. Only familial adenomatous polyposis (FAP) follows mendelian genetics, in that mutations of the APC gene lead to development of the tumours. Lynch syndrome is the most frequent form of hereditary colorectal cancer and appears to be associated with other types of extracolonic cancers.