Dr. Warner obtained her MD and internal medicine training at the University of Toronto and did a medical and radiation oncology fellowship at the Hadassah Ein Karem in Yerushalayim. Since 1993 she has been a staff medical oncologist at the Sunnybrook Odette Cancer Centre and she is a Professor of Medicine at the University of Toronto.

Dr. Warner’s clinical practice and research are devoted entirely to patients with breast cancer. She started the first genetic testing program in Toronto for breast cancer patients and their families, and ran a Canadian study examining the frequency of BRCA1 and BRCA2 mutations in Ashkenazi Jewish women with breast cancer. She was principal investigator of the study that led to the adoption of  breast MRI plus mammography as the standard of care in Canada for screening women at very high risk for developing breast cancer.  Dr. Warner is also the founder and director of PYNK: Breast Cancer Program for Young Women, that addresses the unique clinical, supportive and educational needs of women diagnosed with breast cancer at age 40 or younger. The PYNK leadership team also actively initiates and collaborates on research focusing specifically on  young breast cancer patients.

Dr. Warner is still actively involved in breast cancer research but retired from clinical practice at the end of last August so that she can join the 3 of her 4 children who now live in Israel.