Susan Horwitz

Susan Horwitz elucidated the mechanism of paclitaxel (Taxol) action — demonstrating that it stabilizes microtubules (preventing depolymerization) rather than inhibiting their assembly, causing mitotic arrest. This discovery established a new mechanism of anticancer drug action and explained why paclitaxel was effective against cancer cells. Paclitaxel, isolated from the Pacific yew tree by Monroe Wall and Mansukh Wani, has become one of the most important cancer drugs, widely used in breast, ovarian, lung, and other cancers.