S100A4 and cancer: Cancer-Associated Fibroblasts (CAFs), a bulk of TME cell types, are characterized by the conversion to a synthetic phenotype which could be ascertained by the expression of markers such as α-smooth muscle actin (α-SMA), fibroblast-specific protein-1 (FSP1/S100A4), and fibroblast activation protein (FAP) (Östman and Augsten, 2009).