Cell adhesion molecules (CAMs) are cell-surface molecules grouped into four subclasses based on their structural characteristics: (1) cadherins, (2) the integrin family, (3) selectins, and (4) the immunoglobulin (Ig)-domain containing superfamily of CAMs (Paschos et al., 2009). CAMs are in most cases transmembrane proteins responsible for mediating adhesion of cells to other cells and/or the extracellular matrix (ECM) via their extracellular domains. CAMs provide the “bridge” between the extracellular and intracellular scaffolds; while the extracellular domain mediates adhesion, the intracellular domain interacts with the cytoskeleton (Hulpiau and van Roy, 2009). CAMs are not merely “molecular glue,” as some have been associated with numerous signaling events with major physiological implications (Wheelock and Johnson, 2003; Resink et al., 2009; Takeichi, 2007). CAMs interact with like molecules (hemophilic interactions) and nonlike molecules (heterophilic interaction) on neighboring cells or ECM. This enables cell position and dynamic interactions with other cells through mechanisms that depend on intracellular signaling, ultimately resulting in contact-mediated attraction or repulsion and in chemoattraction or chemorepulsion (Maness and Schachner, 2007). More details are provided below for each of the four CAM subclasses.