Fig. 1
From: Cold and hot tumors: from molecular mechanisms to targeted therapy
Illustrates the mechanisms underlying the anti-tumor immune response and immune evasion. The effectiveness of the anti-tumor immune response hinges on the activation, infiltration, and cytotoxic activity of effector T cells. These crucial processes encompass: a initiation of the T cell-mediated anti-tumor immune response through recognition of tumor-specific antigens (TSAs) in tumor microenvironment; (b) uptake and processing of tumor-specific antigens by dendritic cells (DCs); facilitation of cross-presentation in lymph node draining areas; (c) priming of naive T cells; recruitment of T cells by chemokines in blood vessels; (d) and identification and elimination of tumor cells in tumor microenvironment. Mechanisms of tumor immune evasion include characteristics that (a) diminish tumor immunogenicity, such as the absence of novel antigens, reduced expression of HLA molecules, or interference with antigen presentation to HLA molecules; b defects in antigen presentation possibly linked to dysfunctional DCs, affecting recruitment, activation, maturation, antigen cross-presentation, and T cell priming; c within the tumor microenvironment (TME), restrictions on T cell migration due to inadequate chemokine secretion and compromised chemotactic function of peripheral T cells are observed. Furthermore, abnormal vascular structures and a matrix rich in collagen/fibroblasts impede T cell infiltration. Genetic abnormalities in tumors also hinder T cell migration and infiltration; d Tumors and their immunosuppressive TME play a significant role in inducing T cell dysfunction and apoptosis. Immunotherapy is grounded in principles like tumor antigen release and presentation, T cell priming and activation, T cell migration and infiltration into tumors, and activation of T cell effector functions. Various therapeutic modalities, including chemotherapy, radiotherapy, targeted therapy, and anti-angiogenic therapy, aim to modulate the immune microenvironment and augment the efficacy of immunotherapy. In Fig. 1, the red dashed arrows symbolize effector T cells advancing anti-tumor responses, while the black dashed bars depict obstacles encountered by effector T cells during the anti-tumor response. This figure was created using Figdraw
