FN1 and neoplasm: Importantly, endogenous FN expression in tumor cells has been found to be promoted by upregulation of vimentin during E–M plastic processes [281,282], suggesting again that elevated endogenous FN expression in metastatic CTCs results in better periFN assembly to sustain stability of microtentacles, which not only protect CTCs from mechanical stresses existing in the circulation but also pave ways for CTCs to colonize distant organs.