Theo originally hails from Kalamazoo, Michigan. She earned her M.D. and Ph.D. from Washington University in St. Louis and then did her internal medicine residency at the Brigham and Women's Hospital and her oncology fellowship at the Dana-Farber Cancer Institute all in Boston.

Her first job was at the University of Michigan in Ann Arbor where her clinical work focused on the care of breast cancer patients and her laboratory studied the role of the HIP1 family of proteins in normal and neoplastic biology.

She is an enthusiastic advocate of breast cancer research and MST programs and served as the associate director for the Michigan MSTP. Hence, her UTSW laboratory will expand its horizons to make discoveries in breast cancer genetics and her experiences with the Michigan and Wash U MSTPs will be shared with the UTSW MSTP.