fig2

Figure 2. The tumor microenvironment promotes microbial colonization. The tumor microenvironment promotes microbial accumulation through abnormal vascular permeability, hypoxia-induced metabolic changes, and immunosuppressive conditions. These factors create a favorable niche for microbial survival and colonization within tumors. MHC: Major histocompatibility complex; PD-1: programmed cell death protein 1; PD-L1: programmed death-ligand 1; CTLA-4: cytotoxic T-lymphocyte-associated protein 4; MDSC: Myeloid-derived suppressor cell; Tregs: regulatory T cells; TGF-β: transforming growth factor beta; IL-6: interleukin-6; IL-10: interleukin-10; M2: alternatively activated macrophages.