Effect of low dose metronomic cyclophosphamide therapy on vascular VEGFR2 status. Examples of VEGFR2 positive blood vessels (chevrons) and VEGFR2 negative blood vessels (arrows) are shown in WM239 (A) treated and (B) control and SW480 (C) treated and (D) control subcutaneous xenografts. Scale bar = 50 μm. Quantification of immunofluorescence showed significant decreases in the density of VEGFR2 positive vessels in CTX treated SW480 (E) and WM239 (F) tumors (*p < 0.05). Total VEGFR2 protein levels in tissue lysates were significantly reduced in SW480 tumors treated with CTX (*p < 0.05), but not in treated WM239 tumors (G, H).