结直肠癌是常见的人类消化道恶性肿瘤,在西方发达国家及我国部分地区,其发病率居恶性肿瘤第二位。它的发生、发展是一个涉及多基因、多步骤、多阶段参与的复杂过程,包括癌基因的激活,抑癌基因的缺失或失活,错配修复基因的突变及危险修饰基因改变等。其中抑癌基因的异常在结直肠 Colorectal cancer is a common malignant tumor of human digestive tract, which is the second most common malignant tumor in developed countries in western and some parts of China. Its occurrence and development is a complex process involved in multi-gene, multi-step and multi-stage participation, including activation of oncogenes, deletion or inactivation of tumor suppressor genes, mutation of mismatch repair genes and gene modification of risk modification. One tumor suppressor gene abnormalities in the colorectal