肿瘤分子生物学、分子遗传学的研究证实，癌是由于细胞内基因突变的积累。仅对癌易感的基因突变存在生殖细胞中。更确切地说，导致癌发生的大多数突变是体细胞性的，而且仅存在于受累个体的肿瘤细胞［１］。导致肿瘤形成的突变靶基因有三类：原癌基因、ＤＮＡ修复基因和抑癌基 Cancer molecular biology, molecular genetics studies have confirmed that cancer is due to the accumulation of intracellular genetic mutations. Gene mutations that are only susceptible to cancer are present in germ cells. More precisely, most of the mutations that lead to carcinogenesis are somatic and exist only in the tumor cells of affected individuals [1]. There are three types of target genes that cause tumorigenesis: proto-oncogenes, DNA repair genes and tumor suppressor