Dr. Siu has been a senior medical oncologist at Princess Margaret Cancer Centre since 1998, and has been a professor of Medicine at the University of Toronto since 2009. She is the director of the Phase I Program and codirector of the Bras and Family Drug Development Program at Princess Margaret Cancer Centre, and holds the BMO chair in precision genomics (2016-2021). She is also the clinical lead for the Tumor Immunotherapy Program at Princess Margaret Cancer Centre. Dr. Siu served on the Board of Directors of the American Society of Clinical Oncology for a four-year term (2012-2016). She also served as a member of the Nominating Committee of the American Association for Cancer Research (2014-2016). Her areas of interest are in experimental therapeutics including immuno-oncology agents, head and neck malignancies, and clinical trial designs. She is a scientific editor for Cancer Discovery.