King T I, Murad T M, Waksal S
Am J Pathol. 1978 Dec;93(3):655-60.
The present study was done to ascertain whether a specific carcinogenic agent has a causal effect on the initial proliferation of only one cell type or whether it acts indiscriminately on all cells in the breast secretory unit. Enzymes histochemistry and electron microscopy were performed on DMBA-induced mammary tumors in female Sprague-Dawley rats and on virus-associated spontaneous mammary tumors in C3H/HEJ mice. The results showed that the chemical carcinogen DMBA affects initial myoepithelial cell proliferation, while virus-associated mammary carcinoma originated from ductular epithelial cell proliferation. To determine whether a specific tumor is composed of a single cell type, tumors were grown in tissue culture. The monolayer was fixed in the usual manner for electron microscopy while in Falcon tissue culture plates. The plates were dissolved in xylene and the monolayer was cut into small pieces and embedded in the plastic media. Electron microscopy performed on the tissue culture and the original tissue from the virus-induced tumors showed the presence of viruses in large numbers. It also suggested the differentiation of basal membrane to form basal lamina and apical plasma membrane into microvilli. This study strongly suggests the presence of selective cell carcinogenesis in the mammary gland.
本研究旨在确定一种特定的致癌剂是否仅对一种细胞类型的初始增殖有因果影响，或者它是否对乳腺分泌单位中的所有细胞都有不加区分的作用。对雌性斯普拉格-道利大鼠经二甲基苯并蒽（DMBA）诱导的乳腺肿瘤以及C3H/HEJ小鼠的病毒相关自发性乳腺肿瘤进行了酶组织化学和电子显微镜检查。结果表明，化学致癌物DMBA影响肌上皮细胞的初始增殖，而病毒相关的乳腺癌起源于导管上皮细胞增殖。为了确定特定肿瘤是否由单一细胞类型组成，将肿瘤在组织培养中生长。当在Falcon组织培养板中时，单层以常规方式固定用于电子显微镜检查。将培养板溶于二甲苯，将单层切成小块并包埋在塑料介质中。对病毒诱导肿瘤的组织培养物和原始组织进行的电子显微镜检查显示大量病毒的存在。这也提示了基底膜分化形成基膜，顶端质膜分化为微绒毛。这项研究有力地表明乳腺中存在选择性细胞致癌作用。
