Cancer: Micromanagement of metastasis

Patricia S. Steeg¹

Although they were discovered only in the early 1990s, many regulatory functions of microRNAs — naturally occurring short RNA sequences — have already been reported. The latest news is that they mediate cancer spread.

To successfully spread, or metastasize, a tumour cell must complete a complex set of processes, including invasion, survival and arrest in the circulatory system, and colonization of foreign organs¹. How are these events regulated? In a paper published in this issue (page 682), Ma et al.² propose that microRNAs (miRNAs), which regulate levels of messenger RNAs (mRNAs), coordinate some of the intricate gene-expression programmes implicated in cancer metastasis.

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