The only unequivocal radiological effect of the Chernobyl Nuclear Power Plant accident in 1986 on human health is the increase in thyroid cancer in those exposed in childhood or early adolescence. The Chernobyl Tissue Bank, (CTB: www.chernobyltissuebank.com), was established in 1998 to facilitate access by international scientists to biospecimens and data from patients diagnosed with thyroid tumors post Chernobyl. It has already released more than 11,252 biospecimens to the worldwide research community. The CTB works with the Eastern European Institutes, where patients with thyroid cancer are treated, to collect, document and store samples of tissue and blood from patients. Thyroid cancers are usually small, and much of the tissue is required for an accurate diagnosis for the patient. However, leftover material can be used, with the patient's consent, in research studies. The Coordinating Centre works with the Eastern European Institutes to extract analytes (such as RNA and DNA) from these precious samples, so that many different research projects using different techniques can get access to samples from the same patient. In addition to release of samples, the CTB also collates research data from projects using the Bank, and makes these available to future researchers, which enriches the value of remaining samples from the same patient and enables an integrated or "systems" biology approach to understanding the mechanism involved in thyroid cancer. Thyroid cancer is increasing in incidence worldwide, and information gained from the continued issue of samples and collation of research and clinical outcome data from this project will be of value in the longer term in identifying which patients are at risk of recurrence and death from their disease .The CTB is at the forefront of human tissue banking for research, and the current proposal seeks to widen the use of samples and data stored in the bank to facilitate ongoing and future research projects, including those funded by the NIH.