ABSTRACT
Metastasis is the essential character of biological behaviors in malignancies,which is also the main reason for the death of patients with tumor. So it is very important to research the metastasis for the pre-vention and treatment of carcinomas. Rectal cancer is one of the most common gastrointestinal cancer,and its prognosis is bad. lymphatic metastasis is one important factor in the determination of colon cancer' s progno-sis. More than 50% patients are found lymphatic metastasis when taking operation. The ralationship of lym-phatic metastasis and prognosis is more important than the original tumor's invasiving. So it is meaningful to study the mechanism of tumor metastasis, and to provide a scientific approach to the prediction of tumor me-tastasis, the precise assessment of prognosis and the treatment of tumor metastasis.