Dr. John Dick, Princess Margaret Cancer Centre (image) University Health Network Share Print E-Mail Caption Cancer researchers led by stem cell scientist Dr. John Dick have discovered a pre-leukemic stem cell that may be the first step in initiating disease. Credit UHN Usage Restrictions Credit UHN for photo. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.