MicroRNAs: The Jack of All Trades

Focusing on the pervasive role of microRNAs (miRNAs), we review the multiple steps of malignant transformation, outlining the common hallmarks of tumorigenesis: self-sufficiency in growth signals, insensitivity to growth-inhibitory signals, evasion of apoptosis, limitless replicative potential, sustained angiogenesis, and tissue invasion and metastasis. For each of these traits, we provide examples of miRNA contribution to the acquisition of a malignant phenotype. Finally, through an overview of the remarkable ability of miRNAs to regulate entire pathwaysas a result of the multiplicity of their targets, we highlight the attractive potential of developing miRNAtargeted therapies, which should affect all the aspects of tumorigenesis.