化学致癌物,除烷化剂、亚硝酰胺、碱基类似物、石棉等少数化合物外,绝大多数均需经过靶细胞的代谢活化才能引起致癌作用。苯并(a)芘(简称 Bap,下同)在未经代谢活化之前,在化学结构上是惰性的,不能和细胞大分子起反应,故称前致癌物(Procarcinogen);在代谢过程中,其代谢产物中的一部分可被转化成能与细胞大分子呈共价结合反应的活性成分,这部分活性成分即称终致癌物(Ultimatecarcinogen)。搞清化学致癌物在生物转化过程中所生成的终致癌物类型,是搞清化学致癌机制的关键问题之一。通过最近几年的研究,目前只有 Bap 等极少数物质,其终致癌物类型才得到基本肯定。现简要地加以报导如下:一、Bap 经靶细胞的代谢生成物 Chemical carcinogens, with the exception of alkylating agents, nitrosamines, base analogues, asbestos and a few other compounds, most of them require the metabolic activation of target cells to cause carcinogenesis. Benz(a)pyrene (abbreviated as Bap) is chemically inert before being activated by metabolism and cannot react with cellular macromolecules, so it is called a procarcinogen (Procarcinogen); in metabolic processes, Some of its metabolites can be converted into active ingredients that can covalently bind with macromolecules. This part of the active ingredient is called the ultimate carcinogen. It is one of the key issues to find out the mechanism of chemical carcinogenesis by ascertaining the type of carcinogens generated during the biotransformation of chemical carcinogens. Through the research in recent years, only a few substances such as Bap are currently available, and their ultimate carcinogenic types have been basically confirmed. It is briefly reported as follows: I. Metabolites of Bap by target cells