Akaishi Junko, Onda Masamitsu, Okamoto Junichi, Miyamoto Shizuyo, Nagahama Mitsuji, Ito Kouichi, Yoshida Akira, Shimizu Kazuo
Department of Molecular Biology, Institute of Gerontology, Nippon Medical School, Kanagawa, Japan.
BMC Cancer. 2006 Nov 1;6:260. doi: 10.1186/1471-2407-6-260.
Anaplastic thyroid cancer (ATC) is one of the most aggressive human malignancies and appears to arise mainly from transformation of pre-existing differentiated thyroid cancer (DTC). However, the carcinogenic mechanism of anaplastic transformation remains unclear. Previously, we investigated specific genes related to ATC based on gene expression profiling using cDNA microarray analysis. One of these genes, transcription elongation factor A (SII)-like 4 (TCEAL4), encodes a member of the transcription elongation factor A (SII)-like gene family. The detailed function of TCEAL4 has not been described nor has any association between this gene and human cancers been reported previously.
To investigate the role of TCEAL4 in ATC carcinogenesis, we examined expression levels of TCEAL4 in ACLs as well as in other types of thyroid cancers and normal human tissue.
Expression of TCEAL4 was down-regulated in all 11 ACLs as compared to either normal thyroid tissues or papillary and follicular thyroid cancerous tissues. TCEAL4 was expressed ubiquitously in all normal human tissues tested.
To our knowledge, this is the first report of altered TCEAL4 expression in human cancers. We suggest that loss of TCEAL4 expression might be associated with development of ATC from DTC. Further functional studies are required.
间变性甲状腺癌（ATC）是最具侵袭性的人类恶性肿瘤之一，似乎主要由先前存在的分化型甲状腺癌（DTC）转变而来。然而，间变性转化的致癌机制仍不清楚。此前，我们使用cDNA微阵列分析基于基因表达谱研究了与ATC相关的特定基因。其中一个基因，转录延伸因子A（SII）样4（TCEAL4），编码转录延伸因子A（SII）样基因家族的一个成员。TCEAL4的详细功能尚未描述，此前也未报道该基因与人类癌症之间的任何关联。
为了研究TCEAL4在ATC致癌过程中的作用，我们检测了TCEAL4在间变性甲状腺癌（ACLs）以及其他类型甲状腺癌和正常人体组织中的表达水平。
与正常甲状腺组织或乳头状和滤泡状甲状腺癌组织相比，所有11例间变性甲状腺癌（ACLs）中TCEAL4的表达均下调。TCEAL4在所有检测的正常人体组织中均有普遍表达。
据我们所知，这是首次报道人类癌症中TCEAL4表达改变。我们认为TCEAL4表达缺失可能与DTC发展为ATC有关。需要进一步进行功能研究。
