Gastrin releasing peptide (GRP) and its receptor (GRPR) act as morphogens when expressed in colon cancer (CRC), promoting the assumption of a better differentiated phenotype by regulating cell motility in the context of remodeling; and retarding tumor cell metastasis by enhancing cell-matrix attachment. Although we have shown that these processes are mediated by focal adhesion kinase (FAK), the downstream target(s) of GRP-induced FAK activation are not known. Since osteoblast differentiation is mediated by FAK-initiated up-regulation of ICAM-1 (J Biol Chem 2003; 278: 45368), we determined if GRP-induced activation of FAK alters ICAM-1 expression in CRC; and if so, determine the contribution of ICAM-1 to mediating GRP's morphogenic properties. Caco-2 and HT-29 cells variably express GRP/GRPR. These cells only express ICAM-1 when GRPR are present. In human CRC, GRPR and ICAM-1 are only expressed by better differentiated tumor cells, with ICAM-1 located at the basolateral membrane. ICAM-1 expression was only observed subsequent to GRPR signaling via FAK. To study the effect of ICAM-1 expression on tumor cell motility, CRC cells expressing GRP, GRPR, and ICAM-1 were cultured in the presence and absence of GRPR antagonist or monoclonal antibody to ICAM-1. CRC cells engaged in directed motility in the context of remodeling, and were highly adherent to the extracellular matrix, only in the absence of antagonist or ICAM-1 antibody. These data indicate that GRP up-regulation of ICAM-1 via FAK promotes tumor cell motility and attachment to the extracellular matrix.