Among the 40 cases of CD133-positive expression, the well-differentiated tumors were stained mostly on the membrane or on the both membrane and in the cytoplasm (17 of 19, 89%) but the majority of moderately and poorly differentiated tumors were stained in the cytoplasm or both on the membrane and in the cytoplasm (8/10, 80% and 10/11, 91%, respectively); moreover, by statistical anlysis, the different subcellular localization of CD133 correlated with the differentiation status of the tumor (P = 0.009, Table 2). The gene discussed is PROM1; the disease is neoplasm.