近几年来,人们对涉及人肿瘤发生的某些分子水平的变化有了较深刻的理解。其中,最有趣和最重要的发现之一,就是辨认人肿瘤细胞中特异的点突变。点突变的发现,为基因、致癌剂和癌症之间建立了紧密的联系。最初是通过转染实验发现癌细胞点突变的。人们发现,某些肿瘤细胞的DNA,具有传递受体小鼠NIH-3T3细胞改变了的生长特性的能力。一系列第一流的实验证明,负责转化作用的基因,往往存在于哺乳动物细胞的 In recent years, people have gained a deeper understanding of the changes at certain molecular levels involving human tumors. Among them, one of the most interesting and most important findings is the identification of specific point mutations in human tumor cells. The discovery of point mutations has established a close relationship between genes, carcinogens, and cancer. Initially, cancer cells were found to have been mutated by transfection experiments. It was found that the DNA of certain tumor cells has the ability to transfer the altered growth characteristics of the recipient mouse NIH-3T3 cells. A series of first-rate experiments have shown that genes responsible for transformation are often found in mammalian cells.