Why Tumors that Return Are So Tough (3 of 3) (image) American Association for the Advancement of Science Share Print E-Mail Caption Low-grade tumors have very few actively dividing cells (brown stained cell). After malignant transformation however, they show a dramatic increase in the number of actively dividing cells. This image relates to a paper that appeared in the 12 Dec., 2013, issue of Science Express, published by AAAS. The paper, by Brett E. Johnson at the University of California, San Francisco in San Francisco, CA, and colleagues was titled, "Mutational Analysis Reveals the Origin and Therapy-Driven Evolution of Recurrent Glioma." Credit [Image courtesy of Joseph Costello and Shaun Fouse] Usage Restrictions Please cite the owner of the image when publishing. This image may be freely used by reporters as part of news coverage, with proper attribution. Non-reporters must contact Science for permission. 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.