CD44v6 is a marker for systemic spread in cutaneous T-cell lymphomas. A comparative study between nodal and cutaneous lymphomas.

Adhesion molecules are involved in leukocyte recruitment, lymphocyte recirculation, and in several aspects of tumour biology. Recent discoveries of surface proteins on tumour cells involved in tumour metastasis may explain the invasive behaviour, the migration involving reversible adhesive contacts, the release into the circulation and the extravasation of tumour cells. CD44 is a family of glycoproteins involved in cell-cell and cell-matrix interactions. The v6 (variant exon v6) form of CD44 confers a metastatic potential onto some carcinoma cells. In the present study, the expression of CD44v6 on skin biopsies of 10 inflammatory skin diseases, 30 cutaneous lymphomas (CL), 11 reactive lymph nodes, 10 primary nodal non-Hodgkin's lymphomas (NHL) and 5 secondary nodal NHL was investigated immunohistochemically. None of the 10 nodal NHL were CD44v6 positive for the neoplastic B- or T-cells, whereas 11/12 CL with systemic spread showed a distinct CD44v6 expression in the skin. CD44v6 was not expressed on the tumour cells of skin biopsies of patients without systemic spread (18 cases of CL). In conclusion, CD44v6 expression is connected to an aggressive behaviour of CL.