S100A4 and neoplasm: Many molecules are used as CAF markers, for example, alpha-smooth muscle actin (αSMA), an important marker of differentiated myofibroblasts [11, 14, 21]; S100A4, also named fibroblast specific protein-1 (FSP-1), a calcium-binding protein that has been recognized to play a key role in tumor progression and metastasis [22]; and Vimentin, an intermediate filament-associated protein [18, 23, 24].