The Implication of miRNA Signature in the Characteristic Features and Diagnosis of Lung Cancer

MicroRNAs (miRNA) are noncoding ribonucleic acids (RNAs) that contain ~20–24 nucleotides in length. miRNAs are mainly involved in the posttranscriptional regulation of gene expression. More than 50% of miRNA genes are positioned in cancer-linked genomic regions, which suggests that miRNAs might play a vital role in the development of cancers. Lung cancer (LC) is a well-known malignant growth of tissues or cells in the respiratory organ, which causes death in humans around the world. However, the regulation of differential expressed miRNA remains largely unidentified. In this chapter, we survey the possible implication of miRNAs in targeting certain characteristics that are specific to LC, such as sustaining proliferative signaling (e.g., miRNA-133a, miRNA-346), evading growth suppressors (miRNA-192, miRNA-155), resisting cell death (miRNA-145, miRNA-183), enabling replicative immortality, inducing angiogenesis (miRNA-1, miRNA-135a), activating invasion and metastasis (miRNA-378, miRNA-135b), deregulating cellular energetic (miRNA-143, miRNA-124), evading the immune system (miRNA-141, miRNA-23a), tumor-promoting inflammation (miRNA-101), and genome instability and mutation (miRNA-532-3p, miRNA-500a-3p). Further, experimental advances have facilitated the potential use of miRNA signatures as noninvasive biomarkers for diagnosis of LC. In this chapter, we focus on applications of miRNA biomarkers on diagnosis, histological subtype identification, and differentiation of LC.