Adhesion molecules in the dissemination of non-Hodgkin's lymphomas

Most non-Hodgkin's lymphomas (NHLs) express a number of different adhesion receptors. A large body of evidence indicates that these adhesion receptors not only regulate normal lymphocyte trafficking but also play a pivotal role in the dissemination of NHL. Thus, cutaneous lymphocyte antigen, alpha 4 beta 7, alpha E beta 7, and L-selectin, which mediate the tissue-specific positioning of normal lymphocytes in the skin, mucosa, epithelium and lymph nodes, respectively, are selectively expressed on lymphomas localized at these sites. Furthermore, expression of CD44, a family of adhesion receptors with pleiotropic effects on tumor behavior, is related to lymphoma aggressiveness and dissemination. Taken together, these findings offer a framework for the understanding of tumor dissemination in NHL. In view of the similarities between lymphocyte behavior and the metastatic behavior of solid tumors, these insights might contribute to the understanding of the basic mechanisms underlying tumor metastasis in non-lymphoid tumors.