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BioMed Research International
Volume 2017 (2017), Article ID 9150402, 11 pages
https://doi.org/10.1155/2017/9150402
Research Article

Expression, Mutation, and Amplification Status of EGFR and Its Correlation with Five miRNAs in Salivary Gland Tumours

1Department of Molecular Genetics, Institute of Pathology, Faculty of Medicine, University of Ljubljana, Zaloška Cesta 4, 1000 Ljubljana, Slovenia
2Department of Otorhinolaryngology and Cervicofacial Surgery, University Medical Centre Ljubljana, Zaloška Cesta 2, 1000 Ljubljana, Slovenia
3Institute of Pathology, Faculty of Medicine, University of Ljubljana, Korytkova 2, 1000 Ljubljana, Slovenia

Correspondence should be addressed to Metka Volavšek; is.jl-inu.fm@kesvalov.aktem

Received 14 October 2016; Revised 9 January 2017; Accepted 23 January 2017; Published 9 March 2017

Academic Editor: Gang Liu

Copyright © 2017 Emanuela Boštjančič et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Malignant salivary gland tumours are rare histologically and clinically heterogeneous group of tumours, missing prognostic factors and therapeutic targets. MicroRNAs (miRNAs), small noncoding RNAs, and posttranscriptional regulators of mRNA are poorly described in different subtypes of salivary gland tumours. Epidermal growth factor receptor (EGFR), an important therapeutic target and target of certain miRNAs (i.e., miR-133b), shows variable degrees of expression in salivary gland tumours. Our study included 70 parotid gland tumours of different histological subtypes. Expression, mutations, and copy number variations (CNVs) of EGFR were determined using immunohistochemistry, single-stranded conformation polymorphism, quantitative polymerase chain reaction (qPCR), and fluorescence in situ hybridization. Expression of miR-99b, miR-133b, miR-140, miR-140-3p, and let-7a was analysed using qPCR. Expression of EGFR was observed in 37% of tumours with low and 40% of tumours with high malignant potential. There were no mutations, with the majority of samples showing polysomy of chromosome 7. Based on histological subtypes, we found differential expression of all five miRNAs. We confirmed association of reactivity of EGFR, miR-133b, miR-140, miR-140-3p, and let-7a with CNV of EGFR and a positive association between miR-133b/let-7a and reactivity of EGFR. Age and need for postoperative radiotherapy were characterized as significant in multivariate survival analysis.