MicroRNAs (miRNAs) play important biological roles in cancer development and progression. During the past decade, widespread use of novel high-throughput technologies for miRNA profiling (e.g., microarrays and next-generation sequencing) has revealed deregulation of miRNA expression as a common hallmark of human cancer. Furthermore, miRNAs have been found to be a new class of promising cancer biomarkers with potential to improve the accuracy of diagnosis and prognosis in several hematologic and solid malignancies, as well as to predict response to specific treatments. Recent studies have identified exosome-associated tumor-derived miRNAs in, e.g., blood samples from cancer patients, suggesting that miRNAs may be useful as circulation biomarkers for noninvasive diagnostic testing. In this chapter, we review the current state of development of miRNAs as cancer biomarkers with examples from common human malignancies and discuss remaining barriers to clinical translation. Finally, we describe new emerging classes of noncoding RNAs, including long noncoding RNAs (lncRNAs), with potential as cancer biomarkers. Conceivably, these could be used in combination with miRNAs in molecular diagnostic tests in the future.
Advances in Delivery Science and Technology, 2012, p. 259-298