肿瘤的发生发展是多因素多基因长期作用的结果。克隆肿瘤相关基因的方法有多种，且根据不同的分类有不同的侧重点。本文以研究对象水平的不同概括为三大类：第一类从ＤＮＡ水平入手；第二类以ｍＲＮＡ水平为基础；第三类以蛋白质水平为基础。１　　以ＤＮＡ水平为基础肿瘤相关 The occurrence and development of tumors are the result of the long-term effects of multiple factors and multiple genes. There are many ways to clone tumor-associated genes, and there are different focuses according to different classifications. This article summarizes the differences in the level of research subjects into three categories: the first type starts with the DNA level; the second type is based on the mRNA level; the third type is based on the protein level. 1 Based on DNA level tumor related