The Role of Cancer-Associated Fibroblasts in Cancer Invasion and Metastasis

Simple Summary Cancer metastasis is often associated with a dismal prognosis for the patient. It is, therefore, crucial to understand the mechanisms behind the cascade of events that lead to metastatic disease. Cancer-associated fibroblasts (CAFs) play a key role in cancer progression. Therefore, it is of importance to understand the roles of CAFs in invasion, metastasis, and therapy resistance. Here, we reviewed the crosstalk between CAFs and tumor cells to summarize the current knowledge on CAF roles in cancers to provide the necessary structure to advance the field. Cancer-associated fibroblasts (CAFs) play a key role in cancer progression by contributing to extracellular matrix (ECM) deposition and remodeling, extensive crosstalk with cancer cells, epithelial-to-mesenchymal transition (EMT), invasion, metastasis, and therapy resistance. As metastasis is a main reason for cancer-related deaths, it is crucial to understand the role of CAFs in this process. Colorectal cancer (CRC) is a heterogeneous disease and lethality is especially common in a subtype of CRC with high stromal infiltration. A key component of stroma is cancer-associated fibroblasts (CAFs). To provide new perspectives for research on CAFs and CAF-targeted therapeutics, especially in CRC, we discuss the mechanisms, crosstalk, and functions involved in CAF-mediated cancer invasion, metastasis, and protection. This summary can serve as a framework for future studies elucidating these roles of CAFs.