Small RNAs as Probes into the Biology of Metastasis
Aberrant microRNA (miRNA) expression is a defining feature of human malignancy. Specific miRNAs have been identified as promoters or suppressors of metastatic progression—the primary cause of death from solid cancers. These miRNAs control metastasis by divergent or convergent regulation of metastatic gene pathways. Interestingly, such miRNA-regulatory networks can govern cell-autonomous cancer phenotypes or modulate the cell-extrinsic composition of the metastatic microenvironment. The use of small RNAs as probes into the molecular and cellular underpinnings of metastasis has provided surprising insights into the complexity of the metastatic cascade. These basic studies have also revealed attractive candidates for therapeutic targeting.