目前已证实的致癌物约有千种,分为物理的、化学的、生物的,其中化学品占多数。米勒(Miller)报道很多化学致癌物需经代谢变为有亲电性终端的致癌物,才能同DNA、RNA、蛋白质等结合,使细胞突变进入癌的启动阶段。1954年英国证实一名肝癌病人死亡的原因为亚硝 There are about 1000 kinds of carcinogens that have been confirmed so far, and they are divided into physical, chemical and biological ones, of which chemicals account for the majority. Miller reported that many chemical carcinogens need to be metabolized into electrophilic terminal carcinogens in order to combine with DNA, RNA, proteins, and so on, so that the cell mutations enter the cancer initiation phase. In 1954, the United Kingdom confirmed that the cause of death of a liver cancer patient was nitros