TSG101 and breast cancer: Supporting these conclusions, KO of B4galnt1 (encoding GM2/GD2 synthase) in N2a cells significantly decreased EV secretion, whereas in another study, overexpression of B3GALT4 (encoding GM1 synthase) in a breast cancer cell line increased levels of the EV markers TSG101 and CD63 in EV fractions, suggesting enhanced EV release (74).