In addition to the independent roles of Wnt and Notch signaling pathways intumorigenesis in the colon, the findings that tumor development in Apc-deficientmice is enhanced upon simultaneous activation of Notch and Wnt signals [29] and that manyintestinal tumors display abnormal activation of both pathways [3] suggest a molecular interplaybetween Notch and Wnt signaling in the formation of CRC. The gene discussed is APC; the disease is colorectal carcinoma.