A naturally high rate of genetic mutation in cancers regularly leads to non-functional genes in the CTVT mitochondria, which causes them to lose productivity.

肿瘤自然的高基因突变率通常导致ctvt线粒体基因不能正常工作，造成它们失去了繁殖力。

youdao

Found in most canine breeds throughout the world, the scientists think CTVT is very similar to the transmissible but more fatal cancer seen in the endangered Tasmanian devils of Australia.

在世界各地的大多数犬类身上都有发现CTVT，科学家认为它与澳大利亚濒危动物袋獾身上见到的一种传染性的、但更加致命的肿瘤相似。

youdao

Although it is true in the Tasmanian devil and also in dogs, there is this cancer called Canine Transmissible Venereal Tumor, CTVT, that is essentially a sexually transmitted disease.

NPR: Startling New Evidence Cancer Is Contagious