Histologicaly, microvessel density assessed by immunostaining of PECAM was significantly increased in PBS treated Dll4+/- tumors compared to PBS treated Dll4+/+ insulinomas, while sEphB4-Alb treatment in RT2 Dll4+/+ mice caused a statistically significant decrease of tumor vessel density (Figure 3C). Here, ALB is linked to pancreatic insulinoma.