一个国际科研团队31日公布研究报告称，在野生袋獾种群中肆虐了10多年的致命癌症——袋獾面部肿瘤起源于雪旺细胞，这一发现将有助于开发针对这一恶性肿瘤的疫苗和疗法。

雪旺细胞是神经嵴的衍生物，形成了周围神经髓磷脂轴突的髓鞘。它环绕在末梢神经轴突的轴上，沿着轴突节形成一层髓磷脂髓鞘。雪旺细胞对末梢神经的发育、功能和再生起着重要作用。

科学家从分布在澳大利亚塔斯马尼亚岛14处的袋獾群落中采集了25个袋獾面部肿瘤样本，进行基因分析，结果惊奇地发现，袋獾面部肿瘤起源于雪旺细胞，在大约20年前，袋獾雪旺细胞内的某种基因变异导致了这一癌变。

科学家还发现，袋獾面部肿瘤有别于普通癌症，它能通过互相撕咬或其他身体接触而传播。患病袋獾撕咬或接触其他袋獾后，其体内的癌细胞可以“移植到”对方体内，并在后者体内形成同样的肿瘤。

袋獾面部肿瘤是一种独特癌症，常出现于袋獾面部或嘴部，但通常会扩散至袋獾的内脏，它与另外一种在犬类中传播的恶性肿瘤是世界上仅有的两种可通过上述方式传播的癌症。

“我们的发现在拯救袋獾免于灭绝的赛跑中迈出了一大步。”论文第一作者、澳大利亚国立大学科学家伊丽莎白·默奇森表示。

袋獾是目前世界上体型最大的有袋类食肉动物，主要分布在塔斯马尼亚岛上。自上个世纪90年代以来，袋獾面部肿瘤开始肆虐，致使野生袋獾数量减少了60％。科学家警告说，如不进行干预，这种疾病可能会在未来25年至35年内将野生袋獾消灭殆尽。2009年5月，澳大利亚将袋獾列为濒危物种。

这项研究成果将刊登在2010年1月1日出版的美国新一期《科学》杂志上。

原始出处：

Science 1 January 2010:DOI: 10.1126/science.1180616

The Tasmanian Devil Transcriptome Reveals Schwann Cell Origins of a Clonally Transmissible Cancer

Elizabeth P. Murchison,1,2,*, Cesar Tovar,3 Arthur Hsu,4 Hannah S. Bender,1,2 Pouya Kheradpour,5 Clare A. Rebbeck,1 David Obendorf,3 Carly Conlan,1 Melanie Bahlo,4 Catherine A. Blizzard,3 Stephen Pyecroft,6 Alexandre Kreiss,3 Manolis Kellis,5,7 Alexander Stark,5,7, Timothy T. Harkins,8 Jennifer A. Marshall Graves,2 Gregory M. Woods,3 Gregory J. Hannon,1 Anthony T. Papenfuss4

The Tasmanian devil, a marsupial carnivore, is endangered because of the emergence of a transmissible cancer known as devil facial tumor disease (DFTD). This fatal cancer is clonally derived and is an allograft transmitted between devils by biting. We performed a large-scale genetic analysis of DFTD with microsatellite genotyping, a mitochondrial genome analysis, and deep sequencing of the DFTD transcriptome and microRNAs. These studies confirm that DFTD is a monophyletic clonally transmissible tumor and suggest that the disease is of Schwann cell origin. On the basis of these results, we have generated a diagnostic marker for DFTD and identify a suite of genes relevant to DFTD pathology and transmission. We provide a genomic data set for the Tasmanian devil that is applicable to cancer diagnosis, disease evolution, and conservation biology.

1 Watson School of Biological Sciences, Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
2 Research School of Biology and the ARC Centre of Excellence in Kangaroo Genomics, The Australian National University, Canberra, ACT 0200, Australia.
3 Menzies Research Institute, The University of Tasmania, Hobart, Tasmania 7000, Australia.
4 Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria 3052, Australia.
5 Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
6 Mt. Pleasant Animal Health Laboratories, Department of Primary Industries and Water, Kings Meadows, Tasmania 7249, Australia.
7 Broad Institute of MIT and Harvard, Cambridge, MA 02141, USA.
8 Roche Applied Sciences, Indianapolis, IN 46250, USA.