S100A4 and cancer: Among the activated fibroblasts are cancer-associated fibroblasts (CAF), that are characterized by increased mitotic index, mutations in tumor suppressor genes such as p53 and by increased secretion of growth factors, chemokines and components of extracellular matrix (ECM) [2], [3], changes which all are involved in invasion and tumor growth [4].Widely used CAF markers include α-smooth muscle actin (α-SMA), fibroblast specific protein 1 (FSP1, also known as S100A4) and fibroblast activation protein (FAP, also known as seprase) [5].