Hypertension in Breast Cancer Patients Receiving Bevacizumab

This research study will look at the effect of an anti-angiogenesis medication called Bevacizumab on blood vessels. Anti-angiogenesis medicines fight cancer by cutting off a tumor's blood supply, starving the tumor of nutrients and oxygen. Previous studies have shown these types of drugs can cause hypertension. The purpose of this study is to help researchers better understand why these drugs cause hypertension. This information will assist researchers in learning how to control this side effect.

* Participants will begin this research study within 14 days of starting Bevacizumab, either as part of standard treatment or as part of another clinical trial. * Participants will have an ultrasound test done at baseline, and after completion of their first and second cycles of therapy. * Vital signs and blood tests will be performed a the start of the study, and after completion of the first and second cycles of therapy.