SMAD4 and cancer: Chen et al. focused their study on the interaction between HSPB5 and vascular endothelial growth factor (VEGF) in the context of cancer, and considering previous data from our team and others on the role of the SMAD-dependent TGF-β1 pathway in pulmonary fibrosis and on the role of HSPB5 in this pathway by chaperoning SMAD4 [7], we focused our study on the impact of NCI-41356 on HSPB5/SMAD4 interaction.