Stromal contributions to the carcinogenic process

Tumor-associated stromal cells are dynamic characters that endorse the carcinogenic process in a multitude of ways. The tumor microenvironment plays a crucial role throughout the tumor progression, which includes initiation, growth, invasion, and metastasis. The tumor microenvironment consists of cellular and non-cellular components. Tumor-associated stromal cell types include the microbiome, immune cells including macrophages, dendritic and T-cells, cells associated with blood and lymphatic vessels including pericytes and endothelial cells, fibroblasts, neuronal cells, and adipocytes. The non-cellular components of the microenvironment include matrix proteins and secreted factors. The development of therapies that target the mechanisms by which stromal cells contribute to successful tumorigenesis is major goal of upcoming cancer research. The purpose of this review is to present a comprehensive discussion of the role of each of the tumor-associated stromal cell types in the carcinogenic process with a special focus on target development and therapeutic intervention. © 2016 Wiley Periodicals, Inc.