Cells in the liver microenvironment regulate the process of liver metastasis

The research of liver metastasis is a developing field. The ability of tumor cells to invade the liver depends on the complicated interactions between metastatic cells and local subpopulations in the liver (including Kupffer cells, hepatic stellate cells, liver sinusoidal endothelial cells, and immune-related cells). These interactions are mainly mediated by intercellular adhesion and the release of cytokines. Cell populations in the liver microenvironment can play a dual role in the progression of liver metastasis through different mechanisms. At the same time, we can see the participation of liver parenchymal cells and nonparenchymal cells in the process of liver metastasis of different tumors. Therefore, the purpose of this article is to summarize the relationship between cellular components of liver microenvironment and metastasis and emphasize the importance of different cells in the occurrence or potential regression of liver metastasis. In this work, we summarized the role of different cells in the liver microenvironment in liver metastasis of digestive system tumors. Different resident cells and recruitment cells in the liver can play a dual role in the process of metastasis. The balance of these effects ultimately determines whether tumor cells proliferate, colonize in new sites, enter dormancy, or even die. This review summarizes the different mechanisms of these cells, thus providing some possible therapeutic targets for the occurrence of liver metastasis of digestive system tumors.