Chernobyl Tissue Bank Research Articles

Comparative Analysis of Driver Mutations and Transcriptomes in Papillary Thyroid Cancer by Region of Residence in South Korea.

Radiation exposure is a well-known risk factor for papillary thyroid cancer (PTC). South Korea has 24 nuclear reactors in operation; however, no molecular biological analysis has been performed on patients with PTC living near nuclear power plants. We retrospectively included patients with PTC (n=512) divided into three groups according to their place of residence at the time of operation: inland areas (n=300), coastal areas far from nuclear power plants (n=134), and nuclear power plant areas (n=78). After propensity score matching (1:1:1) by age, sex, and surgical procedure, the frequency of representative driver mutations and gene expression profiles were compared (n=50 per group). Epithelial-mesenchymal transition (EMT), BRAF, thyroid differentiation, and radiation scores were calculated and compared. No significant difference was observed in clinicopathological characteristics, including radiation exposure history and the frequency of incidentally discovered thyroid cancer, among the three groups. BRAFV600E mutation was most frequently detected in the groups, with no difference among the three groups. Furthermore, gene expression profiles showed no statistically significant difference. EMT and BRAF scores were higher in our cohort than in cohorts from Chernobyl tissue bank and The Cancer Genome Atlas Thyroid Cancer; however, there was no difference according to the place of residence. Radiation scores were highest in the Chernobyl tissue bank but exhibited no difference according to the place of residence. Differences in clinicopathological characteristics, frequency of representative driver mutations, and gene expression profiles were not observed according to patients' region of residence in South Korea.

Abstract 980: Genomic characterization of lymph node metastases in papillary thyroid carcinoma following the Chernobyl accident reveals an expression profile specific to metastatic process

Abstract Following the Chernobyl nuclear power plant explosion in Ukraine in 1986, increased childhood exposure to radioactive iodine (131I), which occurred primarily through contaminated food sources, has been consistently associated with increased risk of developing papillary thyroid carcinoma (PTC). Increased frequency of cervical lymph node metastases (LNM) is well recognized in pediatric PTC, including pediatric cases following the Chernobyl accident. We recently leveraged the collection of fresh-frozen tumor tissues from the Chernobyl Tissue Bank to conduct a genomic landscape analysis of 440 cases of PTC that provided new insights into radiation-related molecular characteristics of PTC occurring after the accident (Morton et al., Science 2021). Here, we extend that study to conduct a genomic landscape analysis of LNMs for a subset of 48 PTC cases to investigate the specific genomic alterations occurring in LNM. The analysis set comprised 144 samples, including fresh-frozen treatment-naïve primary and LNM PTC tumor samples as well as matched normal tissue or blood. Overall, the mutational load was highly concordant between primary and metastatic PTC. On average, 50% of somatic single nucleotide variants and 97% structural variants were shared between primary and metastatic PTCs. In contrast, the burden of somatic copy number alterations (SCNA) between primary tumor and LNM pairs was less concordant, particularly for copy number gains, whereas most of the copy number loss was found to be shared between matched pairs. PTC is usually driven by one driver mutation, most often involving the mitogen-activated protein kinase (MAPK) pathway. All driver mutations were shared between primary and metastatic PTC and were clonal; thus, no additional driver mutations were detected in metastatic PTC. Notably, however, the matched pairs in this study disproportionately had fusion drivers (77%), whereas only 23% of the drivers were BRAF V600E and none were RAS mutations. Transcriptome analysis revealed differentially expressed genes (DEGs) in metastatic PTC compared to primary PTC; three-quarters of the DEGs were overexpressed in metastatic PTC. Half of the LNM overexpressed DEGs were members of the HOXC family, which has been linked with epithelial-mesenchymal transition in cancer progression. There was also reduced expression in LNM for the DLX family, which relates to TGF-beta signaling. Our findings did not reveal a relationship between radiation dose and expression profiles in the LNM, comparable to our findings for the primary PTCs. We still observe that the efficiency of the radiation-induced PTC is paramount and subsequent events are directly related to the drivers in the MAPK pathway. For the cervical LNMs, we observed expression profiles not observed in the primary PTC that could give new insights into PTC local metastases. Citation Format: Olivia W. Lee, Danielle M. Karyadi, Chip Stewart, Tetiana I. Bogdanova, Jieqiong Dai, Stephen W. Hartley, Sara J. Schonfeld, Vidushi Kapoor, Marko Krznaric, Meredith Yeager, Amy Hutchinson, Belynda D. Hicks, Casey L. Dagnall, Julie M. Gastier-Foster, Jay Bowen, Mitchell J. Machiela, Elizabeth K. Cahoon, Kiyohiko Mabuchi, Vladimir Drozdovitch, Sergii Masiuk, Mykola Chepurny, Liudmyla Y. Zurnadzhy, Amy Berrington de González, Gad Getz, Gerry A. Thomas, Mykola D. Tronko, Lindsay M. Morton, Stephen J. Chanock. Genomic characterization of lymph node metastases in papillary thyroid carcinoma following the Chernobyl accident reveals an expression profile specific to metastatic process [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 980.

Genetic characterization of medullary thyroid cancer in childhood survivors of the Chernobyl accident

BackgroundRadiation-associated fusion oncogenes play a direct role in papillary thyroid cancer development and pathogenic fusions have recently been reported in medullary thyroid cancer. To date, no studies have evaluated oncogenic events in medullary thyroid cancer in a radiation-exposed population. MethodsSomatic and germline alterations, including RET fusions, were evaluated in paired medullary thyroid cancer tumor and normal samples from the Chernobyl Tissue Bank, a heavily screened population affected by the Chernobyl disaster. ResultsTissue was available for 49 individuals. The median age of diagnosis was 26 years (range 9 to 43 years); 16 were radiation-exposed at a median age of 6 (range 2 days to 17 years). A total of 21 patients harbored germline RET mutations (codons 634[13], 918[5], 790[1], 609[1], and 620[1]); 4 had family history. Sporadic medullary thyroid cancer was identified in 27 patients (RET[18], KRAS[1], RET+KRAS[1], TP53[1], wild type [6]), with 1 RET fusion (1/49;2%). The age at operation for patients with hereditary medullary thyroid cancer was not different than sporadic medullary thyroid cancer (23.5 vs 28 years, P = .063). In sporadic medullary thyroid cancer, radiation was not associated with a difference in age at operation, tumor size, or tumor stage (P > .05). ConclusionIn a heavily screened cohort, genetic analysis revealed germline RET mutations in previously unrecognized probands and a remarkable number of sporadic medullary thyroid cancer cases with a young age at presentation.

Integration of a radiation biomarker into modeling of thyroid carcinogenesis and post-Chernobyl risk assessment.

Strong evidence for the statistical association between radiation exposure and disease has been produced for thyroid cancer by epidemiological studies after the Chernobyl accident. However, limitations of the epidemiological approach in order to explore health risks especially at low doses of radiation appear obvious. Statistical fluctuations due to small case numbers dominate the uncertainty of risk estimates. Molecular radiation markers have been searched extensively to separate radiation-induced cancer cases from sporadic cases. The overexpression of the CLIP2 gene is the most promising of these markers. It was found in the majority of papillary thyroid cancers (PTCs) from young patients included in the Chernobyl tissue bank. Motivated by the CLIP2 findings we propose a mechanistic model which describes PTC development as a sequence of rate-limiting events in two distinct paths of CLIP2-associated and multistage carcinogenesis. It integrates molecular measurements of the dichotomous CLIP2 marker from 141 patients into the epidemiological risk analysis for about 13 000 subjects from the Ukrainian-American cohort which were exposed below age 19 years and were put under enhanced medical surveillance since 1998. For the first time, a radiation risk has been estimated solely from marker measurements. Cross checking with epidemiological estimates and model validation suggests that CLIP2 is a marker of high precision. CLIP2 leaves an imprint in the epidemiological incidence data which is typical for a driver gene. With the mechanistic model, we explore the impact of radiation on the molecular landscape of PTC. The model constitutes a unique interface between molecular biology and radiation epidemiology.

Reconstruction of individual thyroid doses to the Ukrainian subjects enrolled in the Chernobyl Tissue Bank

The Chernobyl Tissue Bank (CTB) is an organisation that collects and stores samples of tumoral thyroid tissue obtained from Ukrainian and Russian subjects who were treated surgically for a thyroid cancer and had been exposed to (131)I from the Chernobyl accident. By 2012, the CTB had collected specimens of thyroid tissue from 2267 residents of Ukraine for the purpose of radiation research. Arithmetic mean thyroid doses and uncertainties have been estimated for all but 24 subjects for whom residence at the time of exposure was not found. The subjects have been classified into six groups or sub-groups according to the type of dosimetry-related information that is available for each of them. Excluding the 325 subjects with negligible radiation exposure, the arithmetic mean of the thyroid dose over all subjects is estimated as 0.4 Gy, with individual values ranging from <1 mGy to 13 Gy. The uncertainties in the individual thyroid dose estimates, characterised by the geometric standard deviations of their probability distributions, range from 1.3 to 8.7, with an arithmetic mean of 3.2.

Iodine-131 Dose Dependent Gene Expression in Thyroid Cancers and Corresponding Normal Tissues Following the Chernobyl Accident

The strong and consistent relationship between irradiation at a young age and subsequent thyroid cancer provides an excellent model for studying radiation carcinogenesis in humans. We thus evaluated differential gene expression in thyroid tissue in relation to iodine-131 (I-131) doses received from the Chernobyl accident. Sixty three of 104 papillary thyroid cancers diagnosed between 1998 and 2008 in the Ukrainian-American cohort with individual I-131 thyroid dose estimates had paired RNA specimens from fresh frozen tumor (T) and normal (N) tissue provided by the Chernobyl Tissue Bank and satisfied quality control criteria. We first hybridized 32 randomly allocated RNA specimen pairs (T/N) on 64 whole genome microarrays (Agilent, 4×44 K). Associations of differential gene expression (log2(T/N)) with dose were assessed using Kruskall-Wallis and trend tests in linear mixed regression models. While none of the genes withstood correction for the false discovery rate, we selected 75 genes with a priori evidence or P kruskall/P trend <0.0005 for validation by qRT-PCR on the remaining 31 RNA specimen pairs (T/N). The qRT-PCR data were analyzed using linear mixed regression models that included radiation dose as a categorical or ordinal variable. Eleven of 75 qRT-PCR assayed genes (ACVR2A, AJAP1, CA12, CDK12, FAM38A, GALNT7, LMO3, MTA1, SLC19A1, SLC43A3, ZNF493) were confirmed to have a statistically significant differential dose-expression relationship. Our study is among the first to provide direct human data on long term differential gene expression in relation to individual I-131 doses and to identify a set of genes potentially important in radiation carcinogenesis.

The Chernobyl Tissue Bank — A Repository for Biomaterial and Data Used in Integrative and Systems Biology Modeling the Human Response to Radiation

The only unequivocal radiological effect of the Chernobyl accident on human health is the increase in thyroid cancer in those exposed in childhood or early adolescence. In response to the scientific interest in studying the molecular biology of thyroid cancer post Chernobyl, the Chernobyl Tissue Bank (CTB: www.chernobyltissuebank.com) was established in 1998. Thus far it is has collected biological samples from 3,861 individuals, and provided 27 research projects with 11,254 samples. The CTB was designed from its outset as a resource to promote the integration of research and clinical data to facilitate a systems biology approach to radiation related thyroid cancer. The project has therefore developed as a multidisciplinary collaboration between clinicians, dosimetrists, molecular biologists and bioinformaticians and serves as a paradigm for tissue banking in the omics era.

The Chernobyl Tissue Bank: integrating research on radiation-induced thyroidcancer

The only unequivocal radiological effect of the Chernobyl accident on human health is theincrease in thyroid cancer in those exposed in childhood or early adolescence.Cancer is a complicated disease and it is unclear whether the mechanism by whichradiation gives rise to cancer differs from that involved in the generation of cancersof the same type by other environmental stimuli. The Chernobyl Tissue Bankwas established in response to the scientific interest in studying the molecularbiology of thyroid cancer after Chernobyl to address this question. The project issupported by the governments of Ukraine and Russia, and financially supported (intotal around US$3 million) by the European Commission, the National CancerInstitute of the USA and the Sasakawa Memorial Health Foundation of Japan.The project began collecting a variety of biological samples from patients on 1October 1988, and has supplied material to 23 research projects in Japan, the USAand Europe. The establishment of the Chernobyl Tissue Bank has facilitatedco-operation between these research projects and the combination of clinical andresearch data provides a paradigm for cancer research in the molecular biologicalage.

Gene Expression Profiles for Radiation-induced Thyroid Cancer

The question whether radiation-induced thyroid cancer differs by its molecular biology from sporadic disease still remains. Studies on tissue from patients who developed thyroid cancer after the Chernobyl accident have provided a unique opportunity to look for biological consequences of low-dose irradiation by comparing the gene expression profile of sporadic papillary thyroid cancer (PTC), whose aetiology is unknown, and PTC induced by internal radiation. So far, four transcriptomic studies comparing radiation-induced and sporadic thyroid cancer have been reported. However, no final conclusion has been drawn regarding the presence of a radiation signature, as either no difference was noted or the reported differences were not sufficiently convincing due to the low number of cases analysed or to the presence of confounding factors. The list of putative biological and clinical factors that may influence the PTC gene expression profile is long, but there are sufficient data reported in the literature to link expression profiles with differing pathological variants of PTC. The comparison of expression profiles in the tumour samples allows the search for a radiation signature, whereas the comparison of expression profiles of the normal contralateral tissues offers a substantial opportunity for assessing the existence of a susceptibility to radiation that could be responsible for tumour development. We have undertaken this analysis as part of a European Union-funded project, GENRISK-T. Gene expression profiles were investigated in tumours that have arisen in the population exposed to fallout from Chernobyl (i.e. born before 26 April 1986) and were compared with profiles of tumours of similar pathology arising in an age-matched population, residing in the same geographical area (same ethnicity) and born after 1 January 1987. RNA samples from these tumours and their contralateral normal tissues were obtained from the Chernobyl Tissue Bank. Several lines of evidence suggest that the predisposition to developing cancer after radiation exposure is variable in the general population and may be measurable from gene expression.

Integrating Research on Thyroid Cancer after Chernobyl — The Chernobyl Tissue Bank

The only unequivocal radiological effect of the Chernobyl accident on human health is the increase in thyroid cancer in those exposed in childhood or early adolescence. In response to the scientific interest in studying the molecular biology of thyroid cancer after Chernobyl, the Chernobyl Tissue Bank was established. The project is supported by the governments of Ukraine and Russia, and financially supported (in total around US$3million) by the European Commission, the National Cancer Institute of the USA and the Sasakawa Memorial Health Foundation of Japan. The project began collecting a variety of biological samples from patients on 1 October 1988, and has supplied material to 21 research projects in Japan, the USA and Europe. The establishment of the Chernobyl Tissue Bank has facilitated co-operation between these research projects and the combination of clinical and research data provides a paradigm for cancer research in the molecular biological age.

PP94 The Chernobyl Tissue Bank – a model for integrating “omics” research on single blocks of tissue

Reelin is the protein defective in reeler mutant mice [I. Bar, C. Lambert de Rouvroit, I. Royaux, D.B. Krizman, C. Dernoncourt, D. Ruelle, M.C. Beckers, A.M. Goffinet, A YAC contig containing the reeler locus with preliminary characterization of candidate gene fragments, Genomics 26 (1995) 543–549; G. D'Arcangelo, G.G. Miao, S.C. Chen, H.D. Soares, J.I. Morgan, T. Curran, A protein related to extracellular matrix proteins deleted in the mouse mutant reeler, Nature 374 (1995) 719–723; S. Hirotsune, T. Takahara, N. Sasaki, K. Hirose, A. Yoshiki, T. Ohashi, M. Kusakabe, Y. Murakami, M. Muramatsu, S. Watanabe, K. Nakao, M. Katsuki, Y. Hayashizaki, The reeler gene encodes a protein with an EGF-like motif expressed by pioneer neurons, Nature Genet. 10 (1995) 77–83]. In the Orleans allele of reeler (symbol: Relnrl-Orl), a 220 nucleotide deletion is present in the 3′ region of the Reelin message, resulting in a frame shift with production of a predicted protein amputated from its C-terminal amino acids. In this study, we first show that the predicted truncated protein indeed exists in Orleans reeler mice, using several anti-Reelin antibodies. Three antibodies are directed against epitopes located in the N-terminal region of the protein, namely: monoclonal antibody CR-50 [M. Ogawa, T. Miyata, K. Nakajima, K. Yagyu, M. Seike, K. Ikenaka, H. Yamamoto, K. Mikoshiba, The reeler gene-associated antigen on Cajal-Retzius neurons is a crucial molecule for laminar organization of cortical neurons, Neuron 14 (1995) 899–912] (epitope region between Reelin residues 251–407), monoclonal antibody G10 (epitope located between amino acids 199 and 244) and the polyclonal antipeptide rp4 (positions 381–399). A fourth antibody, antipeptide rp5, reacts with the C-terminal (3443–3461) Reelin sequence. In normal embryos, all four antibodies stained cells in the marginal zone with features of Cajal-Retzius cells. While N-terminal specific antibodies detected Reelin immunoreactivity in mouse embryos homozygous for the reeler-Orleans mutation, no staining was obtained with the rp5 antibody, showing the presence of a truncated protein. Moreover, although Reelin could be detected at the surface of living Cajal-Retzius cells of normal mice, it was not revealed after vital staining of embryonic cortex from Orleans reeler mice. These results indicate that the C-terminal region of Reelin is essential for its secretion and suggest that the Orleans reeler phenotype is due to defective Reelin secretion rather than to secretion of an inactive protein.

LONG-TERM HEALTH IMPLICATIONS OF THE CHERNOBYL ACCIDENT AND RELEVANT PROJECTS OF THE WORLD HEALTH ORGANIZATION

The past two decades have witnessed dramatic changes in public health governance and international cooperation on the Chernobyl Nuclear Power Plant accident, especially after the end of the Cold War. The World Health Organization (WHO) has committed itself deeply to the public health issues around Chernobyl and has participated in various health projects such as health monitoring and cancer screening. WHO has also been engaged in research activities such as the Chernobyl Tissue Bank, in close collaboration with the Ministries of Health in Belarus, Russia, and Ukraine. In addition to the official report of the Chernobyl Forum "Health Expert Groups" in 2005, the task of WHO is to not only analyze and clarify the global burden of Chernobyl-related illness, but also to promote the well-being of the local residents who suffered chronic low-level radiation exposure from radiation fallout.

Genome-wide gene expression profiling suggests distinct radiation susceptibilities in sporadic and post-Chernobyl papillary thyroid cancers

Papillary thyroid cancers (PTCs) incidence dramatically increased in the vicinity of Chernobyl. The cancer-initiating role of radiation elsewhere is debated. Therefore, we searched for a signature distinguishing radio-induced from sporadic cancers. Using microarrays, we compared the expression profiles of PTCs from the Chernobyl Tissue Bank (CTB, n=12) and from French patients with no history of exposure to ionising radiations (n=14). We also compared the transcriptional responses of human lymphocytes to the presumed aetiological agents initiating these tumours, γ-radiation and H2O2. On a global scale, the transcriptomes of CTB and French tumours are indistinguishable, and the transcriptional responses to γ-radiation and H2O2 are similar. On a finer scale, a 118 genes signature discriminated the γ-radiation and H2O2 responses. This signature could be used to classify the tumours as CTB or French with an error of 15–27%. Similar results were obtained with an independent signature of 13 genes involved in homologous recombination. Although sporadic and radio-induced PTCs represent the same disease, they are distinguishable with molecular signatures reflecting specific responses to γ-radiation and H2O2. These signatures in PTCs could reflect the susceptibility profiles of the patients, suggesting the feasibility of a radiation susceptibility test.

The Chernobyl Tissue Bank, an international collaboration to investigate the relationship between the exposure to radiation in childhood and thyroid cancer

The only unequivocal radiological effect of the Chernobyl accident on human health is the increase in thyroid cancer in those exposed in childhood. In response to the scientific interest in studying the molecular biology of thyroid cancer post-Chernobyl, the Chernobyl Tissue Bank (CTB: www.chernobyltissuebank.com) was established. The project is supported by the governments of Ukraine and Russia, and financially supported (US$3 M) by the European Commission, the National Cancer Institute of the USA, the Sasakawa Memorial Health Foundation of Japan and the World Health Organization. Full informed consent is obtained from donors; each case is subject to pathological review by an international panel. Aliquots of extracted nucleic acid (RNA and DNA from tissue, DNA from blood) serum are made available to researchers worldwide. Quality control is carried out on each extracted tissue and blood sample; the presence of tumour is confirmed by frozen section prior to extraction. 1605 cases have been pathologically reviewed so far; frozen samples are available on 1254. The majority of the cases are papillary carcinomas (924). Paired tumour-normal samples are available; extracted nucleic acid is available on 337 cases. Samples of blood are available from 711 of the 1605 reviewed cases. Material from the project is currently being used for a variety of scientific projects in Europe, the US and Japan, using techniques from cDNA array and comparative genomic hybridization to immunocytochemistry. More than 2000 aliquots of nucleic acid and 5000 paraffin sections have been released. Researchers using the resource agree to provide their results back to the project on a case-by-case basis for entry into the project database in Swansea.

Chernobyl Tissue Bank Project: Pathology Review

Chernobyl Tissue Bank Project: Pathology Review

The Chernobyl Tissue Bank—integrating international research on thyroid cancer

The Chernobyl Tissue Bank (CTB) is a research resource for both ongoing and future studies of the health consequences of the Chernobyl accident. To date, the only cancer to have shown a verified increase is thyroid cancer. The research so far suggests that it is primarily those who were youngest at the time of the accident who show the greatest risk, and the increase is largely restricted to one particular type of cancer of the thyroid follicular cell, papillary carcinoma. The CTB seeks to maximise the amount of information obtained from small pieces of tumour by providing multiple aliquots of RNA and DNA extracted from well documented pathological specimens to a number of researchers world-wide and to conserve this valuable material for future generations of scientists. It exists to promote collaborative, rather than competitive, research on a limited biological resource. The project ensures (a) the best possible diagnostic service is provided to patients and that appropriate ethical consent is obtained for each biological sample; (b) that specimens of thyroid cancer operated on or after 1 October 1998 (the start date of the project) are properly described and sampled; and (c) that materials (frozen tissue, fixed tissue sections, extracted DNA/RNA and blood samples) are available for appropriate research studies. It also provides a diagnosis agreed by internationally recognized pathologists and an archive of material that can be used for current and future studies on radiation related thyroid cancer.

Post Chernobyl NIS thyroid tissue, nucleic acid and data banks and integrated research

The increased incidence of thyroid carcinoma in patients, resident in the contaminated areas of Belarus, Ukraine and Russia and who were aged under 19 at the time of the Chernobyl accident has provided a unique opportunity for the scientific study of a human tumour of known radiation aetiology. It is important that not only the interests of the patients concerned come first, but also that information is not lost that may inform our response to a future accident, or could improve prognosis for those affected. We have therefore set up the first international cooperation—the Newly Independent States Chernobyl Tissue Bank (known by the acronym NISCTB)—that makes available a collection of biological samples from tumours and normal tissues from these patients. Full ethical permission is obtained for each sample and the project is carried out with the agreements of the governments of Belarus, Ukraine and Russia. A full description of the specimen; its location within the thyroid; whether other tumours are present in the gland and the relative locations of material from which RNA and DNA is extracted after frozen section confirmation, together with an internationally agreed diagnosis is recorded on the project database. The database also contains anonymised basic clinical information on each patient donating material to the project. Researchers who obtain material from the NISCTB agree to provide their results to the Coordinating Centre on a case by case basis on completion of their project. We hope that this project will become a paradigm for investigations on the mechanisms of human cancer, and provide a basis that fosters international collaboration in thyroid research.