Dr. Siziopikou serves as Professor and Vice Chair of Pathology for Research at the Department of Pathology and Laboratory Medicine at the University of Arizona. She was also appointed the Inaugural Director of the Ginny L. Clements Breast Cancer Research Institute at University of Arizona Comprehensive Cancer Center, both in Tucson, AZ and holds the Ginny Clements Breast Cancer Clinical Endowed Chair. Before joining the University of Arizona Dr. Siziopikou served as Professor of Pathology and Medicine (Hematology & Oncology), and the Director of Breast Pathology at Northwestern University’s Feinberg School of Medicine and the Robert H. Lurie Comprehensive Cancer Center in Chicago, IL (2009-2025). Dr. Siziopikou established the first subspecialty Breast Pathology Section in The City of Chicago to support the multidisciplinary Breast Cancer Program at Northwestern and the Lurie Cancer Center. Dr. Siziopikou also established the Breast Pathology Fellowship Program at Northwestern and served as the Director of the fellowship from 2010-2022.

Dr. Siziopikou holds numerous national and international leadership roles. She serves in a number of capacities at the United States and Canadian Academy of Pathology (USCAP), the College of American Pathologists (CAP) and the International Society of Breast Pathology (ISBP) as well as on the Lynn Sage Breast Cancer Symposium scientific planning committee. She is an editorial board member for Breast Cancer Research and Treatment and section editor for breast pathology for the Archives of Pathology & Laboratory Medicine.

Dr. Siziopikou is a content expert for the sixth edition of the WHO Classification of Breast Tumors. She has held appointments with the American Association for Cancer Research (AACR), including service on its Pathology in Cancer Research Task Force and since 2022 on the Breast Cancer Research Grants Scientific Review Committee. Dr Siziopikou was a scientific committee member for the European Society for Medical Oncology (EMSO) 2024 and 2025 Congress. She also served on the Program Committee of the San Antonio Breast Cancer Symposium (SABCS) for multiple years and is the current Panel Chair for Pathology at SABCS. Her research area of excellence is translational breast cancer research where state-of-art scientific discovery drives impactful clinical decision making.