Proposal of a Panel of Genes Identified by miRNA Profiling as Candidate Prognostic Biomarkers in Lung Carcinoids
<b><i>Aim:</i></b> To validate the prognostic role of a panel of genes previously uncovered by our group to be specific targets of miRNAs differentially expressed in lung carcinoids with aggressive pathological features. <b><i>Methods:</i></b> Four genes, namely, cyclic AMP response element binding protein-1 (<i>CREBP1</i>), activin A receptor type 2B (<i>ACVR2B</i>), LIM homeobox 2 (<i>LHX2</i>), and Krüppel-like factor 12 (<i>KLF12</i>), were identified in a previous study by our group using in silico analysis to be regulated by 3 miRNAs (miR-409-3p, miR-409-5p, and miR-431-5p) that were shown to be downregulated in aggressive lung carcinoids. These genes were analyzed using real-time PCR in a cohort of 102 lung carcinoids. Fifty high-grade lung carcinomas served as control group. Their expression was correlated with the expression of miR-409-3p, miR-409-5p, and miR-431-5p and with clinical pathological parameters and disease-free survival. <b><i>Results:</i></b> The expression of all but <i>CREBP1</i> gene was significantly different between lung carcinoids and high-grade neuroendocrine carcinomas. <i>ACVR2B</i> and <i>LHX2</i> were significantly inversely correlated with miR-409-3p and miR-409-5p. High levels of <i>ACVR2B</i> and <i>LHX2</i> were significantly associated with atypical histotype, high tumor grade, and higher proliferation Ki-67 index (all <i>p</i> < 0.05). Low levels of <i>KLF12</i> were significantly associated with the presence of necrosis and positive nodal status (all <i>p</i> < 0.05). Finally, low <i>KLF12</i> expression was associated with shorter disease-free survival in lung carcinoids as a whole and in atypical carcinoids, only (all <i>p</i> < 0.001). <b><i>Conclusions:</i></b> <i>ACVR2B</i>, <i>LHX2</i>, and <i>KFL12</i> are novel potential biomarkers associated with aggressive features in lung carcinoids.