Immune Landscape in Tumor Microenvironment: Implications for Biomarker Development and Immunotherapy

Abstract

Integration of the tumor microenvironment as a fundamental part of the tumorigenic process has undoubtedly revolutionized our understanding of cancer biology. Increasing evidence indicates that neoplastic cells establish a dependency relationship with normal resident cells in the affected tissue and, furthermore, develop the ability to recruit new accessory cells that aid tumor development. In addition to normal stromal and tumor cells, this tumor ecosystem includes an infiltrated immune component that establishes complex interactions that have a critical effect during the natural history of the tumor. The process by which immune cells modulate tumor progression is known as immunoediting, a dynamic process that creates a selective pressure that finally leads to the generation of immune-resistant cells and the inability of the immune system to eradicate the tumor. In this context, the cellular and functional characterization of the immune compartment within the tumor microenvironment will help to understand tumor progression and, ultimately, will serve to create novel prognostic tools and improve patient stratification for cancer treatment. Here we review the impact of the immune system on tumor development, focusing particularly on its clinical implications and the current technologies used to analyze immune cell diversity within the tumor.

Melanoma Associated Chitinase 3-Like 1 Promoted Endothelial Cell Activation and Immune Cell Recruitment

“…The tumor microenvironment is actively formed by a long list of actors [ 1 ]. Different cell types beyond cancer cells accumulate within the tumor tissue ranging from endothelial cells to infiltrating immune cells such as macrophages, neutrophils or T cells.…”

Genotype of Immunologically Hot or Cold Tumors Determines the Antitumor Immune Response and Efficacy by Fully Virulent Retargeted oHSV

“…Human tumors vary greatly in the mechanisms by which they evade the immune-mediated anti-tumor protection, and in immune cell composition [ 27 , 28 , 29 , 30 , 31 , 32 ]. On one side are immunogenic tumors (also named “immunologically hot”), characterized by T cell infiltration, Th1 cytokine expression, and drivers of immune-suppression, like immune inhibitory molecules, PD-l/PDL-1 and CTLA-4 axis, IL-10, TGF, and Tregs.…”

“…An intrinsic characteristic that greatly affects tumor response to immunotherapy is the mutational neoantigen load and the related response to ICIs [ 34 , 35 ]. Altogether, in order for murine tumor models to serve as reliable predictors, it is critical that they mirror the diversity in immune landscapes seen in human tumors [ 30 ].…”

MIRS: an AI scoring system for predicting the prognosis and therapy of breast cancer

“…Specifically, each immune cell subset is computationally estimated by reference profiles based on bulk analysis of tissue samples. This is the main drawback because the transcriptional program of immunocytes exhibits high plasticity under tumor microenvironments (17).…”

“…Specifically, each immune cell subset is computationally estimated by reference profiles based on bulk analysis of tissue samples. This is the main drawback because the transcriptional program of immunocytes exhibits high plasticity under tumor microenvironments (17). Secondly, while most studies were used the immune-related characteristics to improve cancer prognosis, only one or two subsets of immunocyte are included and these subsets lack functional variation, thus the treatments based on these indicators fail to achieve satisfactory immune response effects (18).…”