Dr. Macara studies the development of the ducts that form breast tissue, and the mechanisms that can result in the initiation and spread of breast cancer. Most types of cancer arise from epithelial cells. These cells form many of the organs in the body, and arrange themselves into either sheets (such as the skin) or branching ducts (such as kidney, or mammary glands). Epithelial cells are polarized - they have a top and bottom, which differ from one another in form and function. Dr. Macara is studying how polarization occurs, how this process might be disrupted in breast cancer, and how defects in polarization contribute to invasive behavior and metastasis.