MiRNA Molecular Profiles in Human Medical Conditions: Connecting Lung Cancer and Lung Development Phenomena

MiRNAs are endogenous, single stranded ~22-nucleotide non-coding RNAs (ncRNAs) which are transcribed byRNA polymerase II and mediate negative post-transcriptional gene regulation through binding to 3’untranslatedregions (UTR), possibly open reading frames (ORFs) or 5’UTRs of target mRNAs. MiRNAs are involvedin the normal physiology of eukaryotic cells, so dysregulation may be associated with diseases like cancer,and neurodegenerative, heart and other disorders. Among all cancers, lung cancer, with high incidence andmortality worldwide, is classified into two main groups: non-small cell lung cancer and small cell lung cancer.Recent promising studies suggest that gene expression profiles and miRNA signatures could be a useful step in anoninvasive, low-cost and repeatable screening process of lung cancer. Similarly, every stage of lung developmentduring fetal life is associated with specific miRNAs. Since lung development and lung cancer phenomena sharethe same physiological, biological and molecular processes like cell proliferation, development and shared mRNAor expression regulation pathways, and according to data adopted from various studies, they may have partiallyshared miRNA signature. Thus, focusing on lung cancer in relation to lung development in miRNA studies mightprovide clues for lung cancer diagnosis and prognosis.