Waalkes M P, Rehm S
Inorganic Carcinogenesis Section, National Cancer Institute, Frederick Cancer Research and Development Center, Maryland 21702-1201.
J Toxicol Environ Health. 1994 Nov;43(3):251-69. doi: 10.1080/15287399409531920.
Prostatic cancer is a common and frequently lethal malignant disease. In the United States and other countries the incidence and mortality rate of prostate cancer continue to rise. Cancer of the prostate has an extremely complex etiology and appears dependent on a variety of factors, making linkage to a single factor very difficult to detect. Cadmium is a metallic toxin of great environmental and occupational concern. Cadmium exposure has been associated with human prostatic cancer in some, but not all, epidemiologic studies. Some studies indicate that tissue levels of cadmium in the human prostate correlate with malignant disease. Any association between cadmium and prostatic cancer has been controversial, in large part because of a previous lack of relevant animal models. However, several chronic studies in rats revealing a correlation between cadmium exposure and prostatic tumors have been published over the last several years. These include a study of oral cadmium exposure, a route extremely relevant to human exposure. Several of these chronic studies indicate a hormonal dependence of cadmium-induced prostate cancer. Other supportive work continues to accumulate, such as studies showing in vitro malignant transformation of prostatic epithelial cells with cadmium exposure. In addition, there are indications that the primary biologic tolerance system for cadmium (i.e., the metallothionein gene) may be only poorly active in the specific lobes of the rat prostate in which cadmium induces tumors. The induction in rats of prostate cancer by cadmium treatment clearly supports, but does not definitively establish, a possible role for cadmium as an etiological agent in human prostate cancer. Further research, however, will be required to establish the precise role of cadmium in this important human malignancy.
前列腺癌是一种常见且往往致命的恶性疾病。在美国和其他国家，前列腺癌的发病率和死亡率持续上升。前列腺癌的病因极其复杂，似乎取决于多种因素，因此很难找出与单一因素的联系。镉是一种在环境和职业方面备受关注的金属毒素。在一些但并非所有的流行病学研究中，镉暴露与人类前列腺癌有关。一些研究表明，人类前列腺组织中的镉含量与恶性疾病相关。镉与前列腺癌之间的任何关联一直存在争议，很大程度上是因为此前缺乏相关的动物模型。然而，在过去几年里，已经发表了几项关于大鼠的慢性研究，揭示了镉暴露与前列腺肿瘤之间的相关性。这些研究包括一项关于口服镉暴露的研究，这一途径与人类暴露密切相关。其中几项慢性研究表明，镉诱导的前列腺癌存在激素依赖性。其他支持性研究也在不断积累，例如有研究表明，镉暴露可使前列腺上皮细胞在体外发生恶性转化。此外，有迹象表明，镉的主要生物耐受系统（即金属硫蛋白基因）在镉诱导肿瘤的大鼠前列腺特定叶中可能活性很低。镉处理诱导大鼠患前列腺癌，这显然支持但不能确定镉作为人类前列腺癌病因的可能作用。然而，还需要进一步的研究来确定镉在这种重要的人类恶性肿瘤中的精确作用。
