1. ¹Institute of Interdisciplinary Research, School of Medicine, Univertisté Libre de Bruxelles (ULB), Campus Erasme, CP602, route de Lennik 808, Brussels B-1070, Belgium
2. ²Institute of Endocrinology and Metabolism, Kiev 04114, Ukraine
3. ³Service d'Anatomie et de Cytologie Pathologiques, APHP (Hôpital Ambroise Paré), Faculté de Médecine Paris Ile de France Ouest, Université Versailles Saint-Quentin en Yvelines, 9 Avenue Charles de Gaulle, Boulogne 92100, France
4. ⁴South West Wales Cancer Institute/Swansea Clinical School, Singleton Hospital, Sketty Lane, Swansea SA2 8QA, UK

Correspondence: Dr V Detours, E-mail: vdetours@ulb.ac.be

⁵These authors contributed equally to this work.

Received 8 May 2007; Revised 24 July 2007; Accepted 24 July 2007; Published online 21 August 2007.

Abstract

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, -radiation and H₂O₂. On a global scale, the transcriptomes of CTB and French tumours are indistinguishable, and the transcriptional responses to -radiation and H₂O₂ are similar. On a finer scale, a 118 genes signature discriminated the -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 -radiation and H₂O₂. These signatures in PTCs could reflect the susceptibility profiles of the patients, suggesting the feasibility of a radiation susceptibility test.