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. This evidence concerns the gene SFRP1 and renal cell carcinoma.