Novel methods of treating neuroendocrine tumors are provided. In one embodiment, the method comprises administering to a subject in need thereof a therapeutically effective dose of a Wnt antagonist. In one embodiment, the Wnt antagonist is an anti-FZD antibody. In another embodiment, the Wnt antagonist is a soluble FZD receptor polypeptide. In a further embodiment, the Wnt antagonist is an anti-Wnt antibody.