TTLL4 and breast cancer: 2020). Arnold et al. (2020) reported that TTLL4 overexpression in BC cells (MDA‐MB231 and MDA‐MB468 cells) promotes the biogenesis and secretion of EVs. These MDA‐MB231 and MDA‐MB468 cells–derived EVs then increase the permeability of BBB endothelial (hCMEC/D3) cells and enhance their adhesion to MDA‐MB231 and MDA‐M468 (Arnold et al. 2020).