tumor cells (IMAGE) Ural Federal University Caption The lighter the cells, the higher the antitumor activity of the substance. Credit UrFU / Ilya Safarov. Usage Restrictions Photos may be freely used to illustrate this topic, but please credit the author of the image: UrFU / Ilya Safarov. License Original content 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.