摘要Tumor tissues contain cancer cells, other cellular and non-cellular components. Tumor microenvironments consist of cancer cells and various types of stromal cells, cancer associated fibroblasts, bone marrow-derived cells, endothelial cells, and hematopoietic cells, mainly tumor-associated macrophages and tumor-infiltrating lymphocytes. Increasing recent evidence has demonstrated that alteration of tumor microenvironments is deeply implicated in tumor progression and metastasis in gastric cancer (GC) patients. Recent investigations have provided insights into the molecular mechanisms of the interaction between tumor cells and tumor microenvironments. Interactions between cancer cells and their microenvironment with cytokines and microRNA in extracellular vesicles, such as the exosome, can have a substantial impact on tumor characteristics. Alterations in the tumor microenvironment may play a crucial role in facilitating the progression of tumor cells and metastasis, as well as the activation of cell signaling pathways, which are associated with GC cell proliferation and invasion by genetic or epigenetic alterations. In this review, significant molecular insights into the tumor microenvironment, which consist of cancer associated fibroblasts, bone marrow-derived cells, tumor-associated macrophages and tumor-infiltrating lymphocytes; the interactions between cancer cells and their microenvironment; and the clinical impacts of alterations of GC microenvironments will be discussed.