Radiation exposure during childhood is the only well-established risk factor for papillary thyroid carcinoma (PTC). To better define the biologic profile of radiation-induced and sporadic PTC, we compared in these two groups of PTC the expression of cell cycle regulatory proteins and telomere length.
Cell cycle markers (cyclin A, B1, D1, E, and Ki67) were evaluated on 100 PTC specimens (26 radiation-induced and 74 sporadic PTCs). The expression of cell cycle regulators was studied using immunohistochemistry; telomere length heterogeneity was studied using in situ hybridization in a subset of 16 formalin-fixed samples (8 radiation-induced and 8 sporadic PTCs).
At multivariate analysis, only cytoplasmic cyclin E staining was overexpressed in sporadic cases (P = 0.006). The other cell cycle markers and telomere length did not differ significantly between sporadic PTC and radiation-induced PTC.
These markers cannot be used to differentiate radiation-induced from sporadic PTCs.
From the *Laboratoire de Radiobiologie et Oncologie, DSV/DRR/Commissariat à l’Energie Atomique, Villejuif, France; Departments of †Medicine, §Biopathology, and ¶Nuclear Medicine, Institut Gustave Roussy, Villejuif, France; and ‡Unit 605, National Institute of Health and Medical Research (INSERM), Institute Gustave Roussy, University Paris XI, Villejuif, France.
Supported by a grant from Institute Gustave Roussy in the frame of the Diplôme Universitaire Européen de Recherche en Cancérologie Clinique (to M.A). This study was also supported in part by a grant from Electricité de France (to J.C.S.). H. Boukheris received a fellowship from the International Agency for Research on Cancer.
Reprints: Jean Charles Soria, MD, PhD, Department of Medicine, Institute Gustave Roussy, 94805 Villejuif, Cédex, France. E-mail: email@example.com.