Gee A, Specht J M, Kerk D, Moore J D, Drum A S, Elston R A
Department of Biology, Pacific Lutheran University, Tacoma, WA 98447.
Mol Mar Biol Biotechnol. 1994 Feb;3(1):7-12.
Disseminated neoplasia is a leukemia-like disease that occurs in many species of bivalve molluscs worldwide, including the bay mussel (Mytilus trossulus). The etiology of the disease is undetermined, but an early report proposed that the anomalous bivalve cells were actually an invasive parasite rather than cancerous cells of host origin. Comparison of partial sequences of small subunit rRNA from normal and putative cancer cells was performed to resolve this issue. These studies showed a close phylogenetic relationship of the different forms of cancer cells to each other (similarity coefficient, 0.982), to the normal hemocytes (similarity coefficient, 0.990, 0.992), and to the oyster, Crassostrea virginica (similarity coefficient, 0.895-0.927). A large phylogenetic distance separates all 3 mussel hemocyte types from several representative protists (similarity coefficient, 0.702-0.761). These results indicate that the disseminated neoplastic cells in mussels are indeed proliferative host cells and not unicellular parasites.
播散性肿瘤是一种类似白血病的疾病，在世界各地的许多双壳贝类软体动物中都有发生，包括海湾贻贝（Mytilus trossulus）。该疾病的病因尚未确定，但早期报告提出，异常的双壳贝类细胞实际上是一种侵袭性寄生虫，而非宿主来源的癌细胞。为了解决这个问题，对正常细胞和疑似癌细胞的小亚基rRNA的部分序列进行了比较。这些研究表明，不同形式的癌细胞彼此之间（相似系数为0.982）、与正常血细胞（相似系数为0.990、0.992）以及与牡蛎（Crassostrea virginica）（相似系数为0.895 - 0.927）都有密切的系统发育关系。所有3种贻贝血细胞类型与几种代表性原生生物之间存在很大的系统发育距离（相似系数为0.702 - 0.761）。这些结果表明，贻贝中的播散性肿瘤细胞确实是增殖性的宿主细胞，而非单细胞寄生虫。
