NOTCH1 and esophageal squamous cell carcinoma: We found that in Matrigel plug assays, the conditioned medium from the culture of ESCC cells without NOTCH1 expression suppressed the pro-angiogenic capacity as indicated by decreased hemoglobin content and microvascular density; however, the conditioned medium from the culture of ESCC cells with NICD1 expression significantly enhanced this angiogenic phenotypes, suggesting a critical pro-angiogenic role of Notch signaling in ESCC (Fig. 2d).