In breast cancer, complex gangliosides GD3 and 9-O-acetyl-GD3 have been reported to be over-expressed in about 50% of invasive ductal breast carcinoma [13] and the GD3 synthase (GD3S) gene displayed higher expression among estrogen receptor negative breast cancer tumors [14], associated with poor pathohistological grading and a decreased free survival of patients [15]. This evidence concerns the gene ST8SIA1 and breast cancer.