Fig. 2
From: Tumor-associated stromal cells as key contributors to the tumor microenvironment
Continuum of tumor-associated stromal cell phenotypes. We propose the existence of at least five tumor-associated fibroblast subtypes as distinguished by specific markers during the course of tumor progression: MSC-like is the least aggressive as evidenced by lack of remodeling of the extracellular tumor matrix and expression of MSC markers CD105, CD90, CD73, and CD44; Endothelial-like cells, which express CD31; Myofibroblast-like, which are more aggressive “activated” stroma and express alpha-smooth muscle actin (alpha SMA) and tenascin C (TnC); Pericyte-like, which express NG2 and platelet-derived growth factor receptor (PDGFr); and Matrix-remodeling, which are the most aggressive subtype indicated by extensive tumor matrix remodeling, increased expression of FAP and FSP1, and decreased expression of alpha-SMA