['Angiogenic molecular markers such as vascular endothelial growth factor and tumor microvessel density reflect prognosis of human cancers. The present study clarified the usefulness of endothelial marker endoglin (CD 105) by assessing microvessel density in esophageal squamous cell carcinoma (ESCC).', 'We immunohistochemically investigated CD105, CD31, and vascular endothelial growth factor-A VEGF-A expression in primary esophageal squamous cell carcinoma specimens from 142 patients.', 'Microvessel density was 35.9±21.2 for CD105 and 46.3±25.4 for CD31. CD105 microvessel density was significantly associated with tumor length, tumor invasion depth, lymph node metastasis, stage, lymphatic invasion, venous invasion, and VEGF-A expression; its correlation with almost all clinicopathological parameters was stronger than CD31 microvessel density. And significantly better prognosis was achieved in patients with low, compared to high CD105, microvessel density.'] Is endoglin ( CD105 ) a useful marker for evaluating microvessel density and predicting prognosis in esophageal squamous cell carcinoma?