New blood vessels can grow from existing blood vessels in a process called angiogenesis. Limiting new blood vessel growth is a promising approach to treating cancer because tumours require a blood vessel supply to grow larger than two to three millimetres or to metastasize (spread) to other sites. But much remains to be learned about the molecular mechanisms of angiogenesis in tumours. In earlier research, Dr. Michela Noseda and colleagues have shown that a protein called Notch4 can inhibit angiogenesis. Notch arrests growth in the endothelial cells that line the inside of blood vessels, but it's not known how this process occurs. In her current research project, Michela will investigate how the Notch protein prevents endothelial cells from proliferating. Ultimately, she wants to discover whether manipulating Notch activity in tumour blood vessels can induce tumour regression and limit metastasis.