Van Benthem J, Wild C P, Vermeulen E, Winterwerp H H, Den Engelse L, Scherer E
Division of Chemical Carcinogenesis, The Netherlands Cancer Institute, Amsterdam.
IARC Sci Publ. 1988(89):102-6.
Immunocytochemical visualization of O6-methylguanosine (meGua) and 7-meGua shows that DNA methylation by N-nitrosomethylbenzylamine(NMBzA) occurs not only in the target organs for tumour induction by this nitrosamine, the oesophagus and (occasionally) the tongue, but also in other tissues (liver, lung, trachea, tracheal glands and nasal cavity) for which no tumour induction by NMBzA has been reported. Thus, the organotropic carcinogenic action of NMBzA cannot be exclusively ascribed to differences in levels of DNA methylation. Additional determinants of the cancer risk in extra-oesophageal tissues could be the small size of the NMBzA-activating target cell population and a low proliferative activity.
O6-甲基鸟嘌呤（meGua）和7-甲基鸟嘌呤的免疫细胞化学可视化显示，N-亚硝基甲基苄胺（NMBzA）引起的DNA甲基化不仅发生在该亚硝胺诱导肿瘤的靶器官——食管和（偶尔）舌头中，还发生在其他组织（肝脏、肺、气管、气管腺和鼻腔）中，而这些组织尚未有NMBzA诱导肿瘤的报道。因此，NMBzA的器官特异性致癌作用不能完全归因于DNA甲基化水平的差异。食管外组织癌症风险的其他决定因素可能是NMBzA激活靶细胞群体的规模较小以及增殖活性较低。
