致癌作用可以有三种情况:第一,是体细胞突变,如吸烟、放射或其他因素所造成的体细胞基因突变,这是DNA水平的永久性改变;第二,是细胞分化异常,DNA并不改变而只影响基因表达;第三,是由致癌病毒引起转化基因而成癌变。 有关RNA肿瘤病毒的研究已进行了多年,但一直未被重视。本文以Friend病毒为例谈谈RNA肿瘤病毒的作用。Friend病毒是1956年C.Friend发现的,Friend白血病病毒 There are three possible carcinogenic effects. The first is somatic mutations caused by somatic mutations, such as smoking, radiation or other factors, which are permanent changes in DNA levels. The second is abnormal cell differentiation and DNA is not Change and only affect gene expression; the third is caused by the oncogenic virus transformed into carcinogenesis. Research on RNA oncology has been around for years, but has not been taken seriously. In this paper Friend virus as an example talk about the role of RNA tumor virus. Friend virus was discovered by C. Friend in 1956, Friend Leukemia Virus