In contrast to human colon carcinomas and a variety of other tumors, in which Wnt activation involves genetic mutations in downstream signaling components, APC or β-catenin, resulting in upregulation of this pathway [17, 18], our findings have implied that an autocrine Wnt signaling loop plays a role in the etiology of human bone sarcomas. The gene discussed is APC; the disease is colon carcinoma.