In fact, ovarian (ID8) and melanoma (B16) cell lines were transformed to express high levels of PD-L1 or PD-L1 was silenced; PD-L1 promoted cell proliferation in vitro and in vivo, whereas the silenced PD-L1 tumor cells resulted in slower proliferation rates in vitro and tumor load in mice [73]. Here, CD274 is linked to melanoma.