Cell adhesion receptors in lymphoma dissemination.

Regulated lymphocyte trafficking is essential for the control and integration of systemic immune responses. This homing process disperses the immunologic repertoire, guides lymphocyte subsets to the specialized microenvironments that control their differentiation and survival, and targets immune effector cells to sites of antigenic insult. This review discusses data indicating that the adhesion receptors regulating the trafficking of normal lymphocytes are also expressed and functionally active in their malignant counterparts, the non-Hodgkin lymphomas. These "homing receptors" appear to mediate the highly tissue-specific dissemination of specific lymphoma subtypes, such as lymphomas of the mucosa-associated lymphoid tissues and lymphomas of the skin. Furthermore, as a result of their capability to enhance lymphoma dissemination and to transduce signals into the cell, promoting cell growth and survival, adhesion receptors may contribute to lymphoma aggressiveness. Taken together, the data offer a framework for understanding the dissemination routes of non-Hodgkin lymphomas and suggest that adhesion receptors, specifically those of the CD44 family, may present useful tools to predict prognosis in patients with lymphomas. (Blood. 2000;95:1900-1910)