Cancer would be far less threatening a condition if metastasis could be reliably blocked: "Like microscopic inchworms, cancer cells slink away from tumors to travel and settle elsewhere in the body. Now, [researchers report] that new anti-cancer agents break down the looping gait these cells use to migrate, stopping them in their tracks. Mice implanted with cancer cells and treated with the small molecule macroketone lived a full life without any cancer spread, compared with control animals, which all died of metastasis. When macroketone was given a week after cancer cells were introduced, it still blocked greater than 80 percent of cancer metastasis in mice. ... macroketone targets an actin cytoskeletal protein known as fascin that is critical to cell movement. In order for a cancer cell to leave a primary tumor, fascin bundles actin filaments together like a thick finger. The front edge of this finger creeps forward and pulls along the rear of the cell. Cells crawl away in the same way that an inchworm moves. Macroketone latches on to individual fascin, preventing the actin fibers from adhering to each other and forming the pushing leading edge."