Indeed, chemically synthetic HS tetrasaccharides containing unsubstituted GlcN residues, GlcAβ1-4GlcNH3+ (6-O-sulfate)α1-4GlcAβ1-4GlcNH3+ (6-O-sulfate)(TD4-143-1) (Figure 7a), accumulated in lysosomes, inhibited heparanase activity, and suppressed invasion of breast cancer cells in vitro [243]. This evidence concerns the gene HPSE and breast cancer.