TM4SF1 and breast cancer: While the importance of TM4SF1 mediated signaling and protein interactions in metastasis formation have been previously identified26, 35–37 suggesting TM4SF1 as a drug target38–40, we add to the current knowledge by showing that TM4SF1 needs to be palmitoylated to have sufficient plasma membrane localization and thus functionality in breast cancer metastasis growth.