Gene Signature of the Post-Chernobyl Papillary Thyroid Cancer
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CORE Metadata, citation and similar papers at core.ac.uk Provided by Spiral - Imperial College Digital Repository Eur J Nucl Med Mol Imaging DOI 10.1007/s00259-015-3303-3 ORIGINAL ARTICLE Gene signature of the post-Chernobyl papillary thyroid cancer Daria Handkiewicz-Junak1 & Michal Swierniak1,2 & Dagmara Rusinek1 & Małgorzata Oczko-Wojciechowska1 & Genevieve Dom 3 & Carine Maenhaut3 & Kristian Unger4,5 & Vincent Detours 3 & Tetiana Bogdanova 6 & Geraldine Thomas4 & Ilya Likhtarov7 & Roman Jaksik8 & Malgorzata Kowalska1 & Ewa Chmielik9 & Michal Jarzab10 & Andrzej Swierniak11 & Barbara Jarzab1 Received: 11 August 2015 /Accepted: 29 December 2015 # The Author(s) 2016. This article is published with open access at Springerlink.com Abstract Human Genome U133 2.0 Plus) with the aim of identifying Purpose Following the nuclear accidents in Chernobyl and molecular differences between radiation-induced (exposed to later in Fukushima, the nuclear community has been faced Chernobyl radiation, ECR) and sporadic PTC. All participants with important issues concerning how to search for and diag- were resident in the same region so that confounding factors nose biological consequences of low-dose internal radiation related to genetics or environment were minimized. contamination. Although after the Chernobyl accident an in- Results There were small but significant differences in the crease in childhood papillary thyroid cancer (PTC) was ob- gene expression profiles between ECR and non-ECR PTC served, it is still not clear whether the molecular biology of (global test, p < 0.01), with 300 differently expressed probe PTCs associated with low-dose radiation exposure differs sets (p < 0.001) corresponding to 239 genes. Multifactorial from that of sporadic PTC. analysis of variance showed that besides radiation exposure Methods We investigated tissue samples from 65 children/ history, the BRAF mutation exhibited independent effects on young adults with PTC using DNA microarray (Affymetrix, the PTC expression profile; the histological subset and patient Daria Handkiewicz-Junak and Michal Swierniak contributed equally to this work. Electronic supplementary material The online version of this article (doi:10.1007/s00259-015-3303-3) contains supplementary material, which is available to authorized users. * Barbara Jarzab 6 Institute of Endocrinology and Metabolism, Kiev, Ukraine [email protected] 7 Radiation Protection Institute, Academy of Technological Sciences of Ukraine, Kiev, Ukraine 1 Department of Nuclear Medicine and Endocrine Oncology, Maria 8 Systems Engineering Group, Faculty of Automatic Control, Skłodowska-Curie Memorial Cancer Center and Institute of Electronics and Informatics, Silesian University of Technology, Oncology, Gliwice Branch, Wybrzeze Armii Krajowej 15, Gliwice, Poland 44-101 Gliwice, Poland 9 2 Genomic Medicine, Department of General, Transplant and Liver Department of Tumour Pathology, Maria Skłodowska-Curie Surgery, Medical University of Warsaw, Warsaw, Poland Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland 3 Institute of Interdisciplinary Research, Université libre de Bruxelles (ULB), Bruxelles, Belgium 10 IIIrd Department of Radiation Therapy, Maria Skłodowska-Curie 4 Human Cancer Studies Group, Division of Surgery and Cancer, Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Imperial College London Hammersmith Hospital, London, UK Gliwice, Poland 5 Research Unit Radiation Cytogenetics, Helmholtz-Zentrum, 11 Department of Automatic Control, Silesian University of Munich, Germany Technology, Gliwice, Poland Eur J Nucl Med Mol Imaging age at diagnosis had negligible effects. Ten genes (PPME1, time of the Chernobyl accident and resident in the HDAC11, SOCS7, CIC, THRA, ERBB2, PPP1R9A, HDGF, contaminated areas of Ukraine and Russia. The prospective RAD51AP1,andCDK1) from the 19 investigated with quan- nature of the collection means that it now includes patients titative RT-PCR were confirmed as being associated with ra- with thyroid cancer who were born after the radioactive diation exposure in an independent, validation set of samples. iodine released from the accident had decayed in the Conclusion Significant, but subtle, differences in gene ex- environment. The results of two recent studies using pression in the post-Chernobyl PTC are associated with pre- samples provided by the CTB [18, 19] on the gene vious low-dose radiation exposure. expression phenotype of PTC developing after low-dose radiation exposure have been reported. However, differ- Keywords Papillary thyroid cancer . Children . Adolescents . ences were reported only in normal thyroid tissue [19]or Radiation . Gene expression . Transcriptome between tumour and normal tissue in relation to radiation dose, but not as global differences [18, 20]. In contrast, this study searched for global differences in Introduction molecular profiles in tumour tissue from patients who were either exposed to Chernobyl radiation as children (exposed to Following the nuclear accidents in Chernobyl and 25 years Chernobyl radiation, ECR) or were born after 1 January 1987 later in Fukushima, the nuclear community has been faced andthereforenotexposedtoradiation(notexposedto with two important issues: first how to manage radiation con- Chernobyl radiation, non-ECR). Both groups resided in the tamination, and second how to search for and diagnose bio- same areas so that potential confounding factors (e.g. environ- logical consequences of low-dose internal radiation contami- ment) were minimized. Gene expression profiles with respect nation. The biological consequences of radioiodine contami- to intrinsic potential confounding factors including age at PTC nation after the Chernobyl accident were observed as early as diagnosis, mutational status and histological subtype of PTC a few years after the accident when an increase in childhood were also investigated. The study was performed as part of the papillary thyroid carcinomas (PTCs) was demonstrated [1, 2]. GENRISK-T project (EU grant FP6 36495) the aim of which Since then, approximately 5,000 thyroid cancer cases have is to establish whether individual genetic factors influence the occurred in the contaminated regions of Belarus, Ukraine risk of developing cancer of the thyroid after exposure to and Russia, with a persisting increased risk of PTC develop- ionizing radiation. ment in irradiated children [3]. Although the increase in PTC incidence in contaminated regions is well demonstrated, it is still not clear whether the molecular phenotype of PTCs asso- Materials and methods ciated with low-dose radiation exposure differ from that of sporadic PTC. The biological material for gene expression analysis was pro- In small-scale molecular studies comparing radiation- vided by the CTB as aliquots of total RNA from carefully associated thyroid cancers with sporadic ones in patients of selected PTC tumour samples paired with RNA extracted similar age, no differences were observed in the overall fre- from the normal thyroid tissue of the same patient quency of RET/PTC rearrangements, events crucial for the (Supplementary Figure S1), after histopathological review of activation of MAPK cascade [4–12], or in relation to the ra- specimens. After control for RNA and microarray quality, 65 diation dose to the thyroid [13]. On the other hand, some PTC samples were analysed. All biological material was ob- studies have shown only distinct types of RET/PTC rearrange- tained with the informed consent of either the patient or his/ ment in patients with radiation-associated and sporadic cancer her guardian, and following approval of this project by the [10, 11] or a difference between radiation-induced and spo- CTB’s External Review Panel. The CTB samples were sup- radic PTC using immunohistochemical, genomic and proteo- plemented by 24 tumour samples (Supplementary Figure S1) mic approaches [14–16]. However, these results could have collected from Polish patients with differentiated thyroid can- been biased by many confounding factors (for review see cer (DTC) born between 1 January 1987 and 1994, who were Maenhaut et al. [17]) since, except in one study [15], they included in the non-ECR group (only for the validation and were not controlled for the potential impact of genetic and exon array study). All samples were taken during surgery with environmental factors, patient age, histological variant or the approval by local Ethics Committee and informed consent stage of disease. was obtained from all patients. Such a well-balanced comparison study was not possible until the establishment of the Chernobyl Tissue Bank (CTB). 3′ Oligonucleotide microarray study Since 1998, the CTB (www.chernobyltissuebank.com) has been prospectively collecting samples of thyroid tissue taken The study included 33 PTC samples from the ECR group and from surgical specimens from patients aged under 19 at the 32 samples from the non-ECR group, all obtained from the Eur J Nucl Med Mol Imaging CTB. In the ECR group, the patients received a mean thyroid de Bruxelles, Belgium, and the Institute of Oncology in radiation dose of 288 mGy (range 45.4 to 4,595). In seven Gliwice, Poland. Briefly, a subset of 19 Affymetrix CEL files patients (21 %) the radiation dose was higher than 1 Gy and was analysed in both laboratories, Bruxelles and Gliwice, and only in five (15 %) lower than 100 mGy. At the time of PTC the results from the two laboratories for the same tumour and diagnosis, the ECR patients were slightly