PECAM1 and malignant colon neoplasm: To study whether colon adenocarcinoma cells can differentiate into endothelial cells at different levels of differentiation, we cultured three representative colon cancer cells, including HCT116 (poorly differentiated), SW480 (moderately differentiated), and HT29 (well differentiated), in endothelial-inducing conditioned medium (basal medium with 10 ng/mL EGF, 10 ng/mL VEGF, and 5 ng/mL) for 5, 10, and 15 days and examined expressions of endothelial markers, such as CD31, CD34, and VE-cadherin.