S100A4 and metastatic malignant neoplasm: Overall, our results show that the covalent phenylproline inhibitorsare effective and specific inhibitors of the S100A4-NMII interactions.Further investigation and optimization of 5b, which hasthe best solubility and structural data, could produce lead compoundsthat would help to better understand the S100A4-NMII signaling cascadeand could lead to new therapeutics against metastatic cancers.