The Mesd C-terminal region peptide and the full-length Mesd protein block Wnt3a-induced Wnt/β-catenin signaling in LRP5- and LRP6-expressing cells, inhibit Wnt/β-catenin signaling in human breast HS578T cells and prostate cancer PC-3 cells, and inhibit cancer cell proliferation [105]. The gene discussed is WNT3A; the disease is cancer.