In vivo effects of pazopanib on the HCCLM3 xenograft model. Pazopanib inhibited in vivo tumor growth and intratumoral angiogenesis in a subcutaneously implanted HCCLM3 model. Three weeks after the treatment, tumor growth was significantly delayed as compared with the control (A). Microvessels evidenced by anti-CD31 immunostaining were lower in the pazopanib-treated tumors than the tumors treated with vehicle only (B). Endothelial cells formed dilated, disorganized, and tortuous networks in the control, while looking straight and regular in pattern in the pazopanib-treated tumors (B). The density of alpha-smooth muscular actin (α-SMA)-positive pericytes were increased by pazopanib treatment (C). The intratumoral microvessel density reversely correlated with the mean transit time of the contrast flowing through the xenograft tumors detected in the hotspot areas by contrast-enhanced ultrasonography (D). Bars, SD.