大肠癌是常见的恶性肿瘤之一 ,其发生发展是一个多基因多阶段的变化过程。其中癌基因突变激活及抑癌基因失活起重要作用。近年研究表明 ,Ｋ -ｒａｓ癌基因激活和 ｐ５３抑癌基因突变或缺失与大肠癌的发生及发展密切相关。本文以聚合酶链反应 -单链构象多态性 (ＰＣＲ -ＳＳＣＰ Colorectal cancer is one of the common malignant tumors, and its occurrence and development is a multi-gene and multi-stage change process. Among them, oncogene mutation activation and inactivation of tumor suppressor genes play an important role. Recent studies have shown that K-ras oncogene activation and p53 tumor suppressor gene mutation or deletion are closely related to the occurrence and development of colorectal cancer. This article uses polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP).