The Chernobyl (Chornobyl in Ukrainian) Tissue Bank (CTB) is a repository of biological material and data from patients with thyroid tumors who were exposed as children or adolescents to radioactive fallout from the April 26, 1986, accident at the Chernobyl nuclear power plant in Ukraine. The CTB also houses a digital collection of data derived by researchers using our samples.

Since CTB was found in October 1998, the project has been supported by a number of sponsors including the European Commission, the World Health Organization, the U.S. National Cancer Institute (NCI), and the Sasakawa Health Foundation of Japan (SHF). At the time of its founding, the CTB established a Coordinating Center at Imperial College, London, UK. In 2023, the Coordinating Center moved to the Division of Cancer Epidemiology and Genetics at the NCI, part of the National Institutes of Health, which now funds and coordinates the CTB in collaboration with the V.P. Komisarenko Institute of Endocrinology (IEM) and Metabolism of the National Academy of Medical Sciences of Ukraine in Kiev, with the full support of the Government of Ukraine. Initially, Belarus and Russia were included in the project, but those collaborations are currently suspended for political reasons.

The objective of the CTB is to provide a research resource for studies of the health consequences of the Chernobyl accident. It aims to:

• Ensure that specimens of thyroid cancer removed on or after October 1, 1998, are consistently described and sampled; that the materials (extracted tumor and normal DNA/RNA, blood samples, and in some cases fixed tissue sections) along with the demographic, clinical and pathological information, are available for appropriate research studies; and that all specimens and data are collected and shared with appropriate informed consent.
• Review tumor specimens and provide a consensus diagnosis by an international committee of expert pathologists for all cases. Diagnostic information is available to research groups carrying out molecular biological, therapeutic, epidemiological, and other studies.
• Maximize the amount of information obtained from small pieces of tumor and promote collaborative, rather than competitive, research on a limited biological resource.
• Ensure that knowledge pertaining to the consequences of this accident may benefit the patients affected and be of value in responding to future nuclear accidents as well as in understanding and treating thyroid tumors more generally.

The tissue bank is located at the V.P. Komisarenko Institute of Endocrinology and Metabolism (IEM) in Kiev, Ukraine. The staff of the CTB obtains informed consent from patients and prepares and stores their donated materials. (Historically, a separate tissue bank was also maintained in Russia.) The CTB maintains a database of samples and data that are shared via an integrated database managed by the coordinating center. The CTB staff work closely with the coordinating center staff who make key information available to researchers wishing to access the material.

The CTB obtains informed consent for each sample collected and ensures proper description, sampling, and preservation of donated materials (frozen tissue, fixed tissue sections, extracted DNA/RNA and blood samples). The CTB has in place a robust security system to protect patient privacy while ensuring their valuable information is available for research studies.

Each specimen is given a unique identifier. The age, sex, age at operation, oblast, and a measured or calculated dose received are recorded. All data accessible by researchers are anonymized. Standard operating procedures, approved by relevant authorities for each country involved, are followed to ensure privacy.

The CTB currently includes material and information from patients with thyroid carcinomas and cellular follicular adenomas from the contaminated oblasts of Ukraine (Kiev, Kiev city, Cherkasse, Chernigov, Rovno, Zhitomyr and Sumy) who were born after April 26, 1967, (i.e., younger than 19 years of age at the time of the Chernobyl accident), were treated with surgery on or after October 1,1998, at the Institute of Endocrinology and Metabolism in Kiev, Ukraine, and who consent to donate to the project. The CTB also includes patients who were born after the accident, and thus were not exposed to radioactive iodine, as a comparison.

The CTB collects a variety of biospecimen from patients undergoing operations for thyroid cancer or adenoma. Tissue collection follows an approved standard operating procedure (SOP) and is snap frozen whenever possible; the presence or absence of tumor is verified by frozen section. A representative paraffin block is also obtained for each case. Where appropriate, the CTB also collects fresh and paraffin-embedded tissue from loco-regional metastases.

Histological slides from all tumors are reviewed by the CTB Pathology Panel, an international group of expert thyroid pathologists, and a consensus diagnosis agreed before any materials are released to researchers.

Available samples include frozen aliquots of DNA and RNA extracted from normal and neoplastic thyroid tissue and DNA extracted from blood. A frozen section is taken from each portion of tissue before extraction to verify its nature. Quality control is performed on nucleic acid extracted from all tissues and blood samples. In addition, paraffin sections and tissue microarrays are available. Researchers who request access to samples are provided with extracted nucleic acid from thyroid tissue, rather than a small piece of tissue. This maximizes the amount of data that can potentially be obtained from a single specimen and enables multiple molecular biological studies to be carried out for each case. Aliquots of serum are also available.

The CTB website is equipped with a robust search function that allows researchers wishing to access biomaterials to select cases from which they would wish to receive samples. The search function returns information on specimen type, patient characteristics, tumor characteristics, and, for certain tumor specimens, the driver mutation(s) identified to date.

All data generated with samples from the CTB are collected and maintained in an online archive that can be accessed for future studies. Researchers who obtain material from the CTB agree to provide the results of their investigation on a case-by-case basis. This information will not be available until after publication of their findings.