Mochizuki Kunio, Kondo Tetsuo, Oishi Naoki, Tahara Ippei, Inoue Tomohiro, Kasai Kazunari, Nakazawa Tadao, Okamoto Takahiro, Shibata Noriyuki, Katoh Ryohei
Department of Pathology, University of Yamanashi, Yamanashi, Japan.
Pathol Int. 2015 May;65(5):250-3. doi: 10.1111/pin.12270. Epub 2015 Feb 23.
Paired-box gene 8 (PAX8)-peroxisome proliferator-activated receptor-γ (PPARγ) gene fusion has been identified at significant frequency in follicular thyroid carcinomas (FTCs) with cytogenetically detectable translocation t(2;3)(q13;p25). This represents a possible specific molecular marker for follicular carcinoma. In this study, we examined PAX8-PPARγ rearrangement in 24 FTC samples from Japanese patients by reverse transcribed-polymerase chain reaction (RT-PCR) using two upstream PAX8 primers located in exons 7 and 8 and a downstream primer in exon 1 of PPARγ. The fusion gene was detected in only one of 24 FTCs (4%). The FTC with PAX8-PPARγ rearrangement from a 56-year-old man showed a product consistent with fusion between exon 8 of PAX8 and exon 1 of PPARγ. It was confirmed by direct sequencing. This FTC was histologically encapsulated, composed of trabeculae and small follicles and had complete penetration of the capsule by tumor tissues (minimally invasive type). The frequency of the fusion gene in this study was much lower than the 29-63% noted in reports from other countries suggesting that FTCs in Japanese patients may have a special genetic background, and that the high iodine intake from a typical Japanese diet might influence the frequency of the fusion gene in FTCs.
配对盒基因8（PAX8）-过氧化物酶体增殖物激活受体γ（PPARγ）基因融合在细胞遗传学上可检测到易位t(2;3)(q13;p25)的滤泡状甲状腺癌（FTC）中以显著频率被发现。这代表了滤泡状癌一种可能的特异性分子标志物。在本研究中，我们通过逆转录-聚合酶链反应（RT-PCR），使用位于PAX8外显子7和8的两条上游引物以及PPARγ外显子1中的一条下游引物，检测了24例来自日本患者的FTC样本中的PAX8-PPARγ重排情况。在24例FTC中仅1例（4%）检测到融合基因。来自一名56岁男性的具有PAX8-PPARγ重排的FTC显示出与PAX8外显子8和PPARγ外显子1之间融合一致的产物。通过直接测序得以证实。该FTC在组织学上有包膜，由小梁和小滤泡组成，肿瘤组织完全穿透包膜（微侵袭型）。本研究中融合基因的频率远低于其他国家报告中指出的29%-63%，这表明日本患者的FTC可能具有特殊的遗传背景，并且典型日本饮食中的高碘摄入可能会影响FTC中融合基因的频率。
