Pediatric and adult ACCs differ in genetics and many other ways (89, 90), as will be further discussed in Section “Pediatric ACCs: TP53, SF1, and Related Mouse Models.” Although most ACCs arise sporadically, an increased incidence of ACCs has been reported in some genetic syndromes, such as familial adenomatous polyposis (FAP), characterized by mutations in APC and elevated Wnt/β-catenin signaling, and Beckwith–Wiedemann syndrome (BWS), characterized by elevated expression of insulin-like growth factor-2 (IGF2) (91, 92). This evidence concerns the gene APC and Familial adenomatous polyposis.