We then histologically analyzed a total of 16 resected RCC specimens from Akita University for WT1 antigen expression and 13 cases were found to be WT1+ (Figures 4A and 4B), confirming previous reports that RCC express WT1 antigen (Nakatsuka et al., 2006, Iiyama et al., 2007). This evidence concerns the gene WT1 and renal cell carcinoma.