Tumor cells go with the flow

Like the proverbial donkey that follows the carrot, tumor cells follow chemical attractants. Unlike the donkey, however, the tumor cells even make their own carrots, according to a report by Melody Swartz, Jacqueline Shields, Mark Fleury (École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland), and colleagues.

The group was interested in how tumor cells migrate to lymphatic vessels—the first step in malignancy for most carcinomas. Migrating tumor cells express receptors for attractants that lymphatics normally produce to lure immune cells. Shields et al. now show that tumor cells don't need to rely on lymphatics to make the attractants they follow; they can produce the chemicals themselves.

A tumor cell would make no progress, however, if its secreted attractants were all around it. The group therefore...