Abnormal gene expression changes in phenotypically normal, cultured epithelial and stromal cells have been demonstrated in a number of autosomal dominant cancer syndromes, including the Li-Fraumeni syndrome (LFS) [1], BRCA1 and 2, [2], the von Hippel-Lindau (VHL) and the tuberous sclerosis complex (TSC) [3] and familial adenomatous polyposis (FAP) patients [4]. This evidence concerns the gene VHL and Familial adenomatous polyposis.