2005 Volume 50 Issue Supplement1 Pages S87-S89
Radiation etiology is well known in thyroid carcinogenesis. Ret rearrangement is the commonest oncogenic alterations in Chernobyl-related papillary thyroid cancer (PTC). To evaluate whether there is a radiation signature, we analyzed Ret rearrangement in radiation-associated thyroid cancers with fluorescence in situ hybridization (FISH) and reverse transcriptase-polymerase chain reaction (RT-PCR). The FISH analysis demonstrated segmental jumping translocation (SJT) of Ret gene in radiation-associated thyroid cancers but not in sporadic well differentiated PTC. Furthermore, Ret SJT was commonly observed in anaplastic thyroid cancer (ATC) including both radiation-associated and sporadic cancers. In PTC, Ret SJT was restricted to radiation-associated or high-grade cases. Because Ret SJT was not observed in sporadic, well differentiated and low-grade cases of PTC, Ret SJT might be a molecular marker for radiation-induced and/or aggressive cases of PTC. SJTs are unbalanced translocations involving a donor chromosome arm or chromosome segment that has fused to multiple recipient chromosome, and mainly reported in treatment-related leukemias, while very rare in solid cancers. We found SJT in radiation-induced and high-grade thyroid cancers, suggesting chromosomal instability. This is the first report showing SJT in thyroid cancer, and probably the third report showing SJT in solid cancer in vivo.
