MEF2C and Nephroblastoma: In addition, a significant enrichment of the process network, “Cardiac development_BMP_TGFbeta signaling” (mean FDR 6.4e‐05), was identified with increased expression of genes expressed in immature and mature cardiomyocytes including TNNT2, TNNC1, TNNC1, MYL2, MYH6, MYH7, MEF2C, IRX4, and ACTC1. These results show that chemotherapy caused an induction of genes from multiple myocyte differentiation programs in WT1‐mutant Wilms tumor cells in vivo.