The IM7 antibody recognizes CD44, a ubiquitously expressed cell surface receptor which is important for extracellular matrix organization, cell-cell and cell-matrix adhesion and migration. CD44 may be expressed in a number of different isoforms (splice variants) from the most typical or “standard” form, known as CD44s, to variants designated CD44v, e.g. CD44v1 or CD44v6. These receptors interact with several ligands, but most often associate with an extracellular matrix component hyaluronate, through which it mediates adhesion.