According to Science Daily a research group at Karolinska Institutet has developed a DNA-vaccine against DLL4 (a protein which has recently been identified as an important component in regulating the formation of new blood vessels) and the blood vessel tip cells. They have shown that the vaccination against DLL4 causes an immunological antibody response to DLL4, which hinders the growth of breast cancer in mice. Tumors from the vaccinated mice had a tightly packed network of non-functional blood vessels, and poor blood supply. The vaccination did not cause any undesired effects and did not affect the animal’s capacity for wound healing.