A cancer cell breaks away from a primary tumor and settles in a new location, where it once again divides. Pharmaceutical companies typically use simplistic two-dimensional assays for this process, which is known as metastasis, to evaluate anti-cancer therapeutics. In these assays, cells crawl across the surface of a matrix, traveling in a single plane. But a new study indicates that this approach misses some crucial phenomena. (Proceedings of the National Academy of Sciences)
