For the 9 renal tumors with overlapping morphologic features of MA and WT, WT1 and CD57 were positively expressed in both MA-like areas and epithelial WT-like areas, and Ki-67 indices of MA-like areas were 1-5%, less than that in epithelial WT-like areas (5-30%). The gene discussed is WT1; the disease is kidney neoplasm.