Genistein also reduced TOPflash reporter activity in RCC cells and decreased luciferase activity in secreted frizzled related protein 1 (sFRP1), Dickkopf WNT signaling pathway inhibitor 2 (Dkk2), and SMAD Family Member 4 (Smad4) target genes. The gene discussed is DKK2; the disease is renal cell carcinoma.