S100A4 and neoplasm: In fact, many studies including ours have shown that downregulation of S100A4 by siRNA and antisense strategies reduce the invasion and metastatic potential of tumor cells.1–4 Studies on S100A4-interacting proteins have identified various intracellular proteins such as F-actin,5 tropomyosin,6 the heavy chain of nonmuscle myosin-IIA (NMIIA),7,8 Liprin-β1,9 the tumor suppressor p53,10,11 and MDM2.12 These effector proteins indicate an intracellular role for S100A4 in cytoskeletal dynamics, cell motility, cell adhesion, and apoptosis.