Gene signature of the post-Chernobyl papillary thyroid cancer

Purpose: Following the nuclear accidents in Chernobyl and later in Fukushima, the nuclear community has been faced with important issues concerning how to search for and diagnose biological consequences of low-dose internal radiation contamination. Although after the Chernobyl accident an increase in childhood papillary thyroid cancer (PTC) was observed, it is still not clear whether the molecular biology of PTCs associated with low-dose radiation exposure differs from that of sporadic PTC. Methods: We investigated tissue samples from 65 children/young adults with PTC using DNA microarray (Affymetrix, Human Genome U133 2.0 Plus) with the aim of identifying molecular differences between radiation-induced (exposed to Chernobyl radiation, ECR) and sporadic PTC. All participants were resident in the same region so that confounding factors related to genetics or environment were minimized. Results: There were small but significant differences in the gene expression profiles between ECR and non-ECR PTC (global test, p < 0.01), with 300 differently expressed probe sets (p < 0.001) corresponding to 239 genes. Multifactorial analysis of variance showed that besides radiation exposure history, the BRAF mutation exhibited independent effects on the PTC expression profile; the histological subset and patient age at diagnosis had negligible effects. Ten genes (PPME1, HDAC11, SOCS7, CIC, THRA, ERBB2, PPP1R9A, HDGF, RAD51AP1, and CDK1) from the 19 investigated with quantitative RT-PCR were confirmed as being associated with radiation exposure in an independent, validation set of samples. Conclusion: Significant, but subtle, differences in gene expression in the post-Chernobyl PTC are associated with previous low-dose radiation exposure

Major Factors Affecting Incidence of Childhood Thyroid Cancer in Belarus after the Chernobyl Accident: Do Nitrates in Drinking Water Play a Role?

One of the major health consequences of the Chernobyl Nuclear Power Plant accident in 1986 was a dramatic increase in incidence of thyroid cancer among those who were aged less than 18 years at the time of the accident. This increase has been directly linked in several analytic epidemiological studies to iodine-131 (131I) thyroid doses received from the accident. However, there remains limited understanding of factors that modify the 131Irelated risk. Focusing on post-Chernobyl pediatric thyroid cancer in Belarus, we reviewed evidence of the effects of radiation, thyroid screening, and iodine deficiency on regional differences in incidence rates of thyroid cancer. We also reviewed current evidence on content of nitrate in groundwater and thyroid cancer risk drawing attention to high levels of nitrates in open well water in several contaminated regions of Belarus, i.e. Gomel and Brest, related to the usage of nitrogen fertilizers. In this hypothesis generating study, based on ecological data and biological plausibility, we suggest that nitrate pollution may modify the radiationrelated risk of thyroid cancer contributing to regional differences in rates of pediatric thyroid cancer in Belarus. Analytic epidemiological studies designed to evaluate joint effect of nitrate content in groundwater and radiation present a promising avenue of research and may provide useful insights into etiology of thyroid cancer

DOSIMETRY, RADIOEPIDEMIOLOGICAL AND REHABILITATION PROBLEMS AT THE LATE STAGE OF THE CHERNOBYL ACCIDENT

The specification and current status of the dosimetry problems in Ukraine at the late stage of the Chernobyl accident is given. There are: the permanent monitoring of the Chernobyl exposure doses for the inhabitances of the contaminated areas; the improvement of the retrospective dosimetry of whole body exposure at the early stage of the Chernobyl accident; the improvement of the retrospective thyroid dosimetry; dosimetric support of the radioepidemiological studies; the dosimetric maintenance and radiological control of the works for the stabilization and reconstruction of the Object Shelter

ДОЗИМЕТРИЧЕСКИЕ, РАДИОЭПИДЕМИОЛОГИЧЕСКИЕ И РЕАБИЛИТАЦИОННЫЕ ПРОБЛЕМЫ ПОЗДНЕГО ПЕРИОДА ЧЕРНОБЫЛЬСКОЙ АВАРИИ

The specification and current status of the dosimetry problems in Ukraine at the late stage of the Chernobyl accident is given. There are: the permanent monitoring of the Chernobyl exposure doses for the inhabitances of the contaminated areas; the improvement of the retrospective dosimetry of whole body exposure at the early stage of the Chernobyl accident; the improvement of the retrospective thyroid dosimetry; dosimetric support of the radioepidemiological studies; the dosimetric maintenance and radiological control of the works for the stabilization and reconstruction of the Object Shelter.Приводится перечень и современное состояние основных дозиметрических проблем позднего периода Чернобыльской аварии на Украине. К таким проблемам отнесены: постоянный мониторинг доз "чернобыльского" облучения населения; совершенствование системы ретроспективной дозиметрии общего облучения в ранний период Чернобыльской аварии; совершенствование ретроспективной дозиметрии внутреннего облучения щитовидной железы; дозиметрическая поддержка радиоэпидемиологических исследований; дозиметрическое сопровождение и радиологический контроль работ по стабилизации и преобразованию объекта "Укрытие"