To investigate the role of GD3S in preventing p53-mediated apoptosis and promoting tumor growth in vivo, we implanted MCF7 cells stably overexpressing GD3S (MCF7-GD3S-OE) or EV control (MCF7-EV-CTRL) plasmids (2 × 106 cells/mouse) into the mammary fat pads of NSG mice (NOD.Cg-Prkdc Il2rg/SzJ; n = 10 per group) under estradiol treatment (Fig. 6A). Here, CTSG is linked to neoplasm.