At present, it is obvious that FAT1 is abnormally expressed in many kinds of malignant tumors, such as cholangiocarcinoma, breast cancer, oropharyngeal squamous cell carcinoma, diffuse astrocytoma, glioblastoma, acute lymphoblastic leukemia, and so on.[23] RNAi technique was applied to knock down the expression of FAT1 gene in human MB cell line Daoy.[24] It was clear that the proliferation ability of tumor cells is significantly enhanced, suggesting that FAT1 gene may play a role as a tumor suppressor gene in the pathogenesis of MB children. The gene discussed is FAT1; the disease is breast carcinoma.