PPARD and melanoma: However, in experiments where B16-F10 mouse melanoma cells in which PPAR-δ was downregulated using shRNA were subcutaneously injected into syngeneic (C57BL/6) WT or PPAR-δ germline knockout mice [74], PPAR-δ downregulation in either cancer or noncancer cells inhibited metastasis, although this effect was stronger when PPARδ expression was suppressed in cancer cells [86].