CD44 and breast carcinoma: Hyaluronan (HA) binds to multiple cell surface receptors, including hyaluronan-mediated motility receptor (HMMR), commonly referred to as receptor for HA-mediated motility (RHAMM), lymphatic vessel endothelial receptor 1 (LYVE1), and cluster of differentiation 44 (CD44) [5]; however, CD44 is noteworthy, as it is a highly conserved type I transmembrane glycoprotein and a predominant HA receptor widely expressed by the tumor cells of breast carcinomas [21].