APC and Familial adenomatous polyposis: For example, the observed association with hepatoblastoma is supported by the well-established link between APC-related familial adenomatous polyposis and hepatoblastoma29 and between familial adenomatous polyposis and tooth anomalies.30 We also observed associations with other extracranial embryonal tumors in childhood (eg, neuroblastoma and nephroblastoma), and estimates for these cancer types changed little in our sensitivity analysis; this consistency further supports the validity of our findings.