A possible role of several extracellular matrix (ECM) components—heparan sulfate (HS), Syn-1(Syndecan-1) and heparanase (HPSE1)—in light of the influence of ECM alterations on the action of several compounds on the cells and cancer development, was therefore investigated in breast cancer cell resistance to trastuzumab. Here, HPSE is linked to breast carcinoma.