Lung Cancer 83 (2014) 272–278 Contents lists available at ScienceDirect Lung Cancer jou rn al h om epa g e: www.elsevier.com/locate/lungcan Positive prognostic impact of miR-210 in non-small cell lung cancer Marte Eilertsen a,∗ , Sigve Andersen a,b , Samer Al-Saad c,d , Elin Richardsen c,d , Helge Stenvold a,b , Sigurd M. Hald a , Khalid Al-Shibli c,e , Tom Donnem a,b , Lill-Tove Busund c,d , Roy M. Bremnes a,b a Department of Clinical Medicine, University of Tromso, Norway b Department of Oncology, University Hospital of North Norway, Tromso, Norway c Department of Medical Biology, University of Tromso, Norway d Department of Clinical Pathology, University Hospital of North Norway, Tromso, Norway e Department of Pathology, Nordland Central Hospital, Bodo, Norway a r t i c l e i n f o Article history: Received 20 June 2013 Received in revised form 10 October 2013 Accepted 6 November 2013 Keywords: NSCLC Prognosis miR-210 Tumor stromal cells Cancer cells Biomarker a b s t r a c t Objectives: miR-210 is an important regulator of the cellular response to hypoxia. Therefore, we aimed to explore the prognostic significance of miR-210 in non-small cell lung cancer (NSCLC) patients with stage I-IIIA disease. Materials and methods: In addition to clinicopathological and demograpic information, tumor tissues were collected and tissue micro arrays (TMAs) were constructed from 335 patients with stage I-IIIA NSCLC. Expression of miR-210 in cancer cells and stromal cells of the tumor was assessed by in situ hybridization. Results: In univariate analyses, high cancer cell (p = 0.039) and high stromal cell expression (p = 0.008) of miR-210 were both significantly associated with an improved disease-spesific survival (DSS). High co- expression of miR-210 in cancer and stromal cells was also a positive prognostic factor for DSS (p = 0.010). In multivariate analysis, miR-210 in stromal cells (p = 0.011), and miR-210 co-expressed in cancer and stromal cells was an independent prognosticator for DSS (p = 0.011). Conclusions: We show that miR-210 in stromal cells, and co-expressed in cancer cells and stromal cells mediates an independent prognostic impact. It is a candidate marker for prognostic stratification in NSCLC. © 2013 Elsevier Ireland Ltd. All rights reserved. 1. Introduction In industrialized countries, lung cancer has one of the most dis- mal prognoses of all cancers, only 16% will live five years after diagnosis in the United States [1]. Non-small cell lung cancer (NSCLC) constitutes 85% of all lung cancers. The best prognostic system for overall survival in NSCLC is still the TNM (Tumor, Node, Metastasis) staging system [2]. To achieve better treatment and overall NSCLC survival, new predictive and prognostic molecular markers are highly warranted. Micro-ribonucleic acids (microRNA/miRNA) are short sequences of non-protein coding RNA, approximately 22 nucleotides in length [3], that have been researched since their discovery two decades ago [4,5]. miRNAs regulate gene expression by directing a group of enzymes, RNA-induced silencing complex (RISC), to the miRNAs sequence-matching messenger RNA (mRNA) ∗ Corresponding author at: Department of Clinical Medicine, University of Tromso, NO-9037 Tromso, Norway. Tel.: +47 91 12 63 02; fax: +47 77 62 67 79. E-mail address: marte.eilertsen@uit.no (M. Eilertsen). [3]. miRNAs are important regulators in numerous biological processes, including tumorigenesis, and studies have shown that miRNAs are often dysregulated in cancers and can act as both tumor suppressors or oncogenes [6]. microRNA-210 (miR-210) appears as an important regulator of the cellular response to hypoxia and has been called the “micro- manager of the hypoxia pathway” [7]. In malignant disease, hypoxia evolves because of insufficient vasculature supporting the grow- ing number of cancer cells. Regulation of miR-210 is reported to be dependent on the transcription factor HIF1 [8], while others report that miR-210 can be regulated by HIF2 in the absence of HIF1 [9]. The target genes of miR-210 are involved in cell cycle regulation, DNA damage repair, mitochondrial metabolism, tumor growth, apoptosis and angiogenesis [7]. miR-210’s role in cancer is only starting to be clarified and its overall functional impact is reported both as an oncomiR or a tumor suppressor, depending on cancer type [7]. Our research group has examined the prognostic impact in NSCLC of various molecular markers of hypoxia [10–13]. Earlier we have reported a screening study of differentially expressed miR- NAs in a small NSCLC patient cohort, and miR-210 was one of 0169-5002/$ – see front matter © 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.lungcan.2013.11.005