PECAM1 and neoplasm: Immunohistochemistry analysis revealed a downregulation of both the proliferation marker Ki67 and the endothelial marker CD31 (indicating vascular density) from tumor tissues of A549 and H1299 when overexpressing FAM210B (Fig. 2J, K, Fig. S2E), suggesting that FAM210B suppressed xenograft tumor growth and angiogenesis.