Van Beneden R J
Duke University Medical Center, Durham, North Carolina, USA.
Environ Health Perspect. 1994 Dec;102 Suppl 12(Suppl 12):81-3. doi: 10.1289/ehp.94102s1281.
An increase in both the numbers and types of tumors found in finfish and shellfish has been noted in the past several decades. In many cases, while the increase in tumor incidence can be correlated with increases in aquatic toxicant levels, causality cannot be definitively proven. One recent epidemiologic investigation identified the prevalence of gonadal cancers as high as 40% in softshell clams (Mya arenaria) in Maine and 60% in hardshell clams (Mercenaria spp.) from Florida. A second study of these same geographic areas identified human mortality rates due to ovarian cancer as significantly greater than the national average. The rise in mortality rates in humans correlated with the increased use of herbicides in these areas as well as with the appearance of significant numbers of gonadal tumors in the clams. Studies were initiated in our laboratory to examine the molecular basis of these neoplasms in bivalves. NIH3T3 transfection assays were used to examine DNA isolated from these molluscan tumors for the presence of activated oncogenes. DNAs isolated from advanced tumors in both species were able to transform NIH3T3 cells and induce tumors in athymic mice. Studies are now underway to identify the gene(s) detected by these assays and also to examine the molecular mechanisms of toxic response of herbicide-exposed clams.
在过去几十年中，人们注意到鱼类和贝类中发现的肿瘤数量和类型都有所增加。在许多情况下，虽然肿瘤发病率的增加可能与水生毒物水平的升高有关，但因果关系无法得到明确证实。最近的一项流行病学调查发现，缅因州软壳蛤（砂海螂）的性腺癌患病率高达40%，佛罗里达州硬壳蛤（ Mercenaria spp.）的患病率为60%。对这些相同地理区域的另一项研究发现，因卵巢癌导致的人类死亡率明显高于全国平均水平。人类死亡率的上升与这些地区除草剂使用的增加以及蛤类中大量性腺肿瘤的出现有关。我们实验室启动了相关研究，以检查双壳贝类中这些肿瘤的分子基础。利用NIH3T3转染试验检测从这些软体动物肿瘤中分离的DNA中是否存在激活的癌基因。从这两个物种的晚期肿瘤中分离的DNA能够转化NIH3T3细胞并在无胸腺小鼠中诱发肿瘤。目前正在进行研究，以确定这些试验检测到的基因，并研究接触除草剂的蛤类的毒性反应分子机制。
