In accordance with this important role, overexpression of TRα1 in the intestinal epithelium (vil‐TRα1 mice) in a mutated‐Apc background (vil‐TRα1/Apc+/1638N mice) is responsible for the acceleration of tumor appearance, progression, and aggressiveness compared with Apc‐only mutants [14]. This evidence concerns the gene APC and neoplasm.