RET rearrangements in familial papillary thyroid carcinomas

Familial papillary thyroid carcinoma (FPTC) is an inherited tumor character ized by a more aggressive phenotype than that of its sporadic counterpart. Its mode of inheritance as well as its genetic and molecular bases are stil l poorly understood. On the contrary, genetic alterations in sporadic papil lary thyroid carcinoma (PTC) are better characterized, the most common one involving the activation of the proto-oncogene RET through somatic rearrang ements. In the present study, we investigated by interphase fluorescence in situ hybridization the presence of RET rearrangements in a series of 20 FP TC. We show that one FPTC and the adenoma from the same patient carry a RET rearrangement (type PTC1) and that this rearrangement is absent in the ger maline. Furthermore, we excluded a RET haplotype sharing in two brothers of the same family. These results show that RET rearrangements can indeed be found in FPTC and confirm that RET is not involved in the inherited predisp osition to FPTC. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved .