NCAM (CD56)-POSITIVE MALIGNANT-LYMPHOMA

CD56 has been found to identify an isoform of the neural cell adhesion (NCAM). NCAM is a member of the immunoglobulin superfamily of cell ad hesion molecules; it is related to a variety of leukocyte antigens and to several cell adhesion molecules believed relevant to malignant beh avior in a variety of neoplasms. It contains polysialic acid, which ap pears to regulate binding avidity of NCAM and other cell adhesion proc esses. We have identified a group of NCAM-positive lymphomas. Compared to a group of NCAM-negative lymphomas, this group exhibited frequent involvement of unusual sites and a generally aggressive course. Anothe r series of CD56-positive hematolymphoid malignancies has recently bee n described, from Hong Kong; this group also exhibited involvement of unusual sites and displayed a very aggressive course. Together these s eries suggest that NCAM on lymphoma is of biological and clinical sign ificance in terms of tumor behavior and spread.