Abstract:In the process of colorectal cancer metastasis, the tumor microenvironment interacts with primary tumors, secondary tumors, circulating tumor cells, and disseminated tumor cells. This article introduces its dynamic evolution process. The tumor microenvironment can not only exert its host defense mechanism to kill cancer cells, but also help cancer cells metastasize and spread through changes in the composition and structure of the microenvironment. Cancer cells complete their invasion, infiltration, circulation, extravasation, and seeding processes through phenotype transformation, secretion of cytokines, and cell dormancy.