Survivin Delta Ex3 Overexpression in Thyroid Malignancies Joanna Waligo ´ rska-Stachura 1 , Miroslaw Andrusiewicz 2 , Nadia Sawicka-Gutaj 1 , Maciej Biczysko 3 , Anna Jankowska 2 , Marta Kubiczak 2 , Agata Czarnywojtek 1 , Elz _bieta Wrotkowska 1 , Marek Ruchala 1 * 1 Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan ´ , Poland, 2 Department of Cell Biology, Poznan University of Medical Sciences, Poznan ´ , Poland, 3 Department of General, Gastroenterological and Endocrine Surgery, Poznan University of Medical Sciences, Poznan ´, Poland Abstract Context: Thyroid cancer incidence has increased significantly during the past decades and is the most common type of endocrine malignancy. Many factors in thyroid cancers were studied as independent predictors of a poor prognosis. Objective: The objective of the study was to evaluate survivin expression – BIRC5 and its splice variants: survivin delta Ex3 and survivin 2B in benign and malignant thyroid nodules. Design: Thyroid tissues samples from a group of 50 patients consisting of: 29 patients with thyroid cancers (including medullary, papillary, follicular and undifferentiated types), as well as from 21 patients with non-cancerous thyroid tissues (including: 11 benign thyroid lesions and 10 healthy thyroid samples). Main Outcome Measures: The analysis of the survivin gene expression and evaluation of the level of splice variants were performed using quantitative RT-PCR. Results: A statistically significant higher level of expression of survivin gene – BIRC5 was detected in thyroid malignant nodules, when compared with benign lesions and healthy thyroid samples. Moreover, the comparison of survivin relative expression in different staged tumors (pT1, pT3, and pT4) revealed a much higher amount of BIRC5 transcripts in tumor tissues of pT3/pT4. The comparison of survivin expression between benign thyroid nodules and healthy thyroid did not reveal significant differences. Importantly, high expression rate of the survivin delta Ex3 splice variant characterized thyroid carcinomas. Conclusion: The results suggest that survivin, especially survivin delta Ex3 splice variant being overexpress, is a characteristic feature of thyroid malignancy. Citation: Waligo ´ rska-Stachura J, Andrusiewicz M, Sawicka-Gutaj N, Biczysko M, Jankowska A, et al. (2014) Survivin Delta Ex3 Overexpression in Thyroid Malignancies. PLoS ONE 9(6): e100534. doi:10.1371/journal.pone.0100534 Editor: Anthony W.I. Lo, The Chinese University of Hong Kong, Hong Kong Received March 12, 2014; Accepted May 23, 2014; Published June 19, 2014 Copyright: ß 2014 Waligo ´ rska-Stachura et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This paper was supported by The Polish Committee for Scientific Research Award nr N N402 523640. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * Email: mruchala@ump.edu.pl Introduction Thyroid cancer is the most common type of endocrine malignancy [1]. Well-differentiated thyroid cancers arise from follicular cells and encompass papillary, follicular and Hu ¨rthle cell carcinomas. Several different tumor-associated antigens have been described for endocrine malignancies. Clinical and histopatholog- ical parameters affecting the course of disease and patient prognosis such as male gender, advanced age, large tumor size, differentiation status and lymph node or distant metastases, have been studied for thyroid cancer [2]. The best known molecules involved in thyroid tumorigenesis include those of RTK/RAS/ BRAF/MAP kinase pathway, which is suggested to be involved in the development of papillary thyroid carcinoma (PTC) - the most common type of thyroid cancer. In fact, RAS oncogenes were the first ones to be associated with thyroid cancer, and their mutations were found in benign and malignant follicular neoplasms and in follicular variant PTC [1]. The BRAF mutations are the most common genetic disorder in PTC, found in about 83% of studied cases [3]. However, there are mutations in other genes such as: proto-oncogene RET, MET and VEGFR leading to medullary thyroid cancer [4]. Recently, survivin gene polymorphism and its expression as a prognostic value in thyroid cancer was postulated [5,6,7]. Survivin is an anti-apoptotic protein abundantly expressed in a variety of neuroendocrine cancer cells, including pheochromocytoma and GEP tumor cells [8,9]. Its presence was shown also in various human benign neoplasms, such as breast adenomas, Bowen’s disease, colon polyps and benign tumors, derived from the nervous system [10,11,12,13]. In malignant tumors, survivin expression correlates with poor prognosis, local recurrence and shorter, disease-free survival [14,15,16,17,18,19]. Therefore, it is suggested PLOS ONE | www.plosone.org 1 June 2014 | Volume 9 | Issue 6 | e100534