Altered integrin expression patterns shown by microarray in human cutaneous melanoma Laura Vizkeleti a,b , Timea Kiss a,b , Viktoria Koroknai a,b , Szilvia Ecsedi a,b , Orsolya Papp a , Istvan Szasz a,b , Roza Adany a,b and Margit Balazs a,b A large variety of molecular pathways in melanoma progression suggests that no individual molecular alteration is crucial in itself. Our aim was to define the molecular alterations underlying metastasis formation. Gene expression profiling was performed using microarray and qRT-PCR to define alterations between matched primary and metastatic melanoma cell lines. These data were integrated with publicly available unmatched tissue data. The invasiveness of cell lines was determined by Matrigel invasion assays and invasive clones from primary melanoma-derived cell lines were also selected. Two metastatic cell line models were created: the regional lymph node WM983A–WM983A INV –WM983B and the distant lung WM793B–WM793B INV –1205Lu metastatic models. The majority of metastasis genes were downregulated and enriched in adhesion and ITGA6-B4 pathways. Upregulation of immune pathways was characteristic of distant metastases, whereas increased Rap1 signaling was specific for regional (sub)cutaneous metastases. qRT-PCR analysis of selected integrins (A2, A3, A4, A9, B5, B8, A6, B1, and B3) highlighted the possible importance of ITGA3/4 and B8 in the metastatic process, distinguishing regional and distant metastases. We identified functionally relevant gene clusters that influenced metastasis formation. Our data provide further evidence that integrin expression patterns may be important in distant metastasis formation. Melanoma Res 27:180–188 Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. Melanoma Research 2017, 27:180–188 Keywords: cell line invasivity, gene expression microarray, integrins, melanoma metastasis a Department of Preventive Medicine, Faculty of Public Health and b MTA-DE Public Health Research Group, University of Debrecen, Debrecen, Hungary Correspondence to Margit Balázs, PhD, DSc, University of Debrecen, Faculty of Public Health, Department of Preventive Medicine, Kassai Street 26/b, 4028 Debrecen, Hungary Tel: + 36 524 60190x77151; e-mail: balazs.margit@sph.unideb.hu Received 10 May 2016 Accepted 12 December 2016 Introduction Melanocyte-derived malignant melanoma is among the most challenging malignancies to treat, with an increasing incidence and high mortality worldwide [1]. The meta- static process is the predominant cause of melanoma- specific death, markedly decreasing survival rates. Effective treatments that considerably extend the life expectancy of patients with advanced-stage melanoma are still not available [2]. Recent efforts have shown that a large variety of molecular pathways are associated with disease development and progression, thus suggesting that no individual molecular alteration is crucial in these processes. Therefore, the identification of novel metastasis-specific biomarkers is essential to improving both tumor prognosis and disease management [3,4]. The rapid development of microarray technology provides a huge opportunity to discover prognosis-related genetic and gene expression signatures [5–7]. These high-throughput screening technologies have been used extensively in cancer research to identify tumor subclasses, predict disease outcomes and define genes associated with drug resistance. However, these studies face several obstacles, including the scarcity of samples, the heterogeneous nature of this malignancy and the wide variety of platforms and statistical methods used, thus making the prediction of the clinical– biological outcome and efficacy of these patterns relative to current clinical practices uncertain [8–10]. In contrast to breast cancer, in which the breakthrough MammaPrint 70 gene signature provides an opportunity to enhance tumor classification, prognosis, and outcome prediction [11,12], such a set of prognosis-related genes does not exist for melanoma. Surgical resection and sentinel lymph node monitoring remain the leading treatment option. Classical prognostic markers for melanoma have only limited pre- dictive power at the individual level and do not directly aid in decision-making between the limited treatment options [8,13]. In recent years, efforts have been made to evaluate and standardize methodical approaches to enable compar- ison of results derived from different microarray studies [14–16]. Because of the limited availability of cryopreserved tissue samples, relatively few genetic and gene expression studies in matched primary and metastatic melanomas have been carried out [17–20]. In the present study, our aim was to define molecular alterations underlying metastasis formation and to determine the extent to All supplementary digital content is available directly from the corresponding author. 180 Original article 0960-8931 Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/CMR.0000000000000322 Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.