WT1 and Nephroblastoma: On the other hand, although WT1 behaves as a tumor suppressor gene in Wilms’ tumors, increasing data suggest a role for WT1 as an oncogene in both leukemia and solid tumors (Osaka et al., 1997; Sera et al., 2008; Desmedt et al., 2009; Brett et al., 2013).