title: RET/PTC rearrangements arising from a small population of papillary thyroid carcinoma cells, possible candidate for passenger mutation.
abstract: RET rearrangements (RET/PTC) is a major genetic alteration in papillary thyroid carcinomas. However, the prevalence of RET/PTC differs considerably among investigators, and its impact on cancer progression has been controversial. In the current study, we applied interphase fluorescence in situ hybridization (FISH) to touch imprint cytology of 14 papillary thyroid carcinomas along with reverse-transcription polymerase chain reaction (RT-PCR) analysis. FISH DNA probes included RET locus, and PCR primers were designed targeting RET/PTC1 or RET/PTC3. Split FISH signals of RET was observed in 78.6% (11/14) of tumors. Proportions of tumor cells having split RET signals ranged from 1.8% to 19.6% (mean 9.7%) in those 11 tumors. In RT-PCR analysis, RET/PTC was found in 28.6% (4/14) of tumors. Among tumors with split RET signals, 36.4% (4/11) of tumors exhibited detectable messenger RNA of RET/PTC1 or RET/PTC3. The remaining seven tumors with split RET signals had no RET/PTCs amplicon. In conclusion, the current study disclosed that RET/PTCs occur in a small population of tumor cells in papillary thyroid carcinomas. Even though RET/PTC is a specific genetic event in the carcinomas, our results suggested the possibility of RET/PTC as "passenger" abnormalities rather than "driver" oncogenic mutation during thyroid cancer progression, warranting further studies on mechanisms and implication of RET gene instability.
authors.affiliation: Department of Pathology, University of Yamanashi Interdisciplinary Graduate School of Medicine and Engineering, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan. tadaon@yamanashi.ac.jp
authors.forename: Tadao
authors.initials: T
authors.lastname: Nakazawa
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Murata
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kondo
authors.forename: Dongfeng
authors.initials: D
authors.lastname: Niu
authors.forename: Kunio
authors.initials: K
authors.lastname: Mochizuki
authors.forename: Tomonori
authors.initials: T
authors.lastname: Kawasaki
authors.forename: Tetsu
authors.initials: T
authors.lastname: Yamane
authors.forename: Nobuki
authors.initials: N
authors.lastname: Nakamura
authors.forename: Ryohei
authors.initials: R
authors.lastname: Katoh
mesh_terms: D000328:Adult; D002291:Carcinoma, Papillary / Q000235:genetics*; D002879:Chromosomes, Human, Pair 10; D005260:Female; D015321:Gene Rearrangement; D006657:Histones / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D009154:Mutation; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D013964:Thyroid Neoplasms / Q000235:genetics*
chemical_list: D006657:Histones; D015514:Oncogene Proteins, Fusion; D011505:Protein-Tyrosine Kinases; C093573:ret-PTC fusion oncoproteins, human