Targeting the Microtubules (image) University of Warwick Caption Researchers at Warwick Medical School have found that the minuscule tracks of a cellular railway system have a line of weakness, which tends to crack and cause the tracks to dissolve. Cancer drugs already target these microscopic railway tracks, which are called microtubules and are a thousand times thinner than a human hair. Credit Prof. Robert Cross, Warwick Medical School Usage Restrictions This image may only be used with appropriate caption or credit. 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.