A large number of molecules have been identified and characterized which mediate (1) homing of lymphoid cells to lymphoid tissues; (2) localization of cells within distinct microenvironments; and (3) cell-cell and cell-matrix interactions within those microenvironments. B lymphocytes express these adhesion receptors during stages of normal ontogeny. Malignant B cells can also express these adhesion molecules, and they probably serve a "normal" function in a neoplastic state. However, the aberrant expression and/or function of adhesion receptors may in part explain the clinical and biological behavior of these diseases. Further insight into the normal function of these surface molecules may provide novel approaches with which to consider the regulation of growth and dissemination of these cells in vivo, thereby suggesting new therapeutic approaches.