**3. Potential cell membrane CS/DS-carrying PGs of breast carcinoma**

Malignant neoplasms exhibit changes in production of PGs (Bumol and Reisfeld, 1982; Iozzo, 1985; Iozzo, 1988; Stylianou et al., 2008). The variation, abundance and function of CS/DS-GAGs are also affected by the expression of the PG core protein presenting them. Therefore, it is imperative to study these polysaccharides in the context of their carrying PG. PG are involved in signaling and tumorigenicity and their attached GAG contributes to their functions. There is a growing list of PGs that have been implicated as possessing CS/DS side chains (Esko et al., 1999; Taylor and Gallo, 2006). PGs that may be modified by CS/DS chains include aggrecan, neurocan, brevican, bamacan, a CD44 isoform, chondroitin sulfate proteoglycan 4 (CSPG4), syndecans, betaglycan, serglycin, versican, decorin, biglycan, and endocan, most of which are extracellular matrix PGs. Our focus is on the cell membrane PGs that are able to bind to P-selectin (Monzavi-Karbassi et al., 2007). CD44 variants (CD44v), CSPG4, syndecan-1 (SDC-1) and syndecan-4 (SDC-4) are among the cell surface candidates (Faassen et al., 1992; Jackson et al., 1995; Barbareschi et al., 2003; Burbach et al., 2003; Baba et al., 2006; Gotte et al., 2007; Wang et al., 2010). Recently, It has been demonstrated that substantial fraction of neuropilin-1 (NRP-1), a membrane glycoprotein, is a PG modified with either HS or CS-GAG chains (Shintani et al., 2006).

Many articles are now devoted to CD44 in cancer stem cells and its role in cancer progression and metastasis (Lesley et al., 1997; Naor et al., 1997; Lesley and Hyman, 1998; Kalish et al., 1999; Toole, 2009). Here we focus on SDC-1, SDC-4, CSPG4 and NRP-1 as potential CS-carrying PGs on the surface of breast tumor cells.
