Tumour microenvironment immune milieu (TME immune milieu)

The tumour microenvironment (TME) immune milieu refers to the complex and dynamic ecosystem of immune cells, signaling molecules, and extracellular components that surround and interact with malignant cells. This milieu includes a variety of cell types such as T cells, B cells, natural killer cells, macrophages, myeloid-derived suppressor cells (MDSCs), and fibroblasts, all of which are influenced by a network of cytokines, chemokines, and growth factors (Binnewies et al., 2018, Nature Medicine). In many cancers, the TME is characterized by an immunosuppressive state that allows the tumor to evade detection and destruction by the host immune system. This is often achieved through the upregulation of immune checkpoints, the recruitment of regulatory immune cells, and the creation of a hypoxic or nutrient-deprived environment (Pitt et al., 2016, Annals of Oncology). Therapeutic strategies targeting the TME immune milieu aim to shift the balance from a pro-tumorigenic, immunosuppressive environment to an anti-tumorigenic, immunostimulatory one. The most prominent examples are immune checkpoint inhibitors, which block proteins like PD-1 or CTLA-4 to reactivate exhausted T cells (Pardoll, 2012, Nature Reviews Cancer). Other approaches include targeting tumor-associated macrophages, inhibiting TGF-beta signaling, or using anti-angiogenic agents to normalize the tumor vasculature and enhance the delivery of immune cells and drugs. Understanding the heterogeneity and spatial organization of the TME immune milieu is critical for predicting patient response to immunotherapy and developing more effective combination treatments (Chen & Mellman, 2017, Nature).

Other names

Tumor microenvironmentTMEImmune microenvironmentTumor-infiltrating immune cellsCancer immune landscape

Drugs targeting the TME immune milieu typically work by blocking inhibitory checkpoints (e.g., PD-1/PD-L1, CTLA-4), depleting immunosuppressive cells (e.g., Tregs, MDSCs), neutralizing pro-tumor cytokines (e.g., TGF-beta, IL-6), or inhibiting angiogenesis to improve immune cell infiltration.