PECAM1 and melanoma: Considering the increased intercalation of YUMM1.1-BrM4 melanoma cells into PECAM-1-ko pMBMECs in vitro, we asked whether YUMM1.1-BrM4 melanoma cells also showed increased extravasation across the BBB in PECAM-1-ko C57BL/6J mice in vivo.