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多年来,肿瘤基础研究及临床实践表明,癌症的演变过程中,正常细胞不是直接转化成癌细胞的,癌症是经过几个过程或多个阶段逐步形成的.当前,癌变的二阶段学说已普遍被人们所接受.第一阶段称为引发阶段(initia-tion stage),正常细胞在致癌物质引发下变成引发性细胞(initation cell),但这种细胞在未演变成癌细胞前,如无适当的条件,一般不进一步向第二阶段发展.第二阶段称为促癌阶段(promotion stage),这时细胞分裂增加,一
Over the years, basic tumor research and clinical practice have shown that during the evolution of cancer, normal cells do not directly transform into cancer cells, and cancer is gradually formed through several processes or stages. Currently, the second-stage doctrine of cancer has become widespread. It is accepted by people. The first stage is called the initiation stage. Normal cells become initiating cells when triggered by carcinogens. However, if cells do not evolve into cancer cells, they will be The appropriate conditions are generally not further developed to the second stage. The second stage is called the promotion stage. At this time, the cell division increases.