DISTRIBUTION OF EXTRACELLULAR-MATRIX COMPONENTS AND THEIR RECEPTORS IN HUMAN LYMPHOID-TISSUE AND B-CELL NON-HODGKIN LYMPHOMAS

In this study the distribution patterns of various extracellular matri x components and their receptors (i.e, beta 1 integrins) in B-cell non -Hodgkin lymphomas were examined and compared to those in reactive lym phoid tissue, Neoplastic follicles within follicular lymphomas showed similar patterns to that observed in reactive follicles, which appeare d to be strongly associated with the presence of follicular dendritic cells, Diffuse lymphomas of low and intermediate malignancy grade reve aled features comparable to those of interfollicular areas of reactive lymphoid tissue, irrespective to which compartment the tumour cells w ere related, Highly malignant lymphomas, however, displayed unique ext racellular matrix configurations, resulting from active matrix degrada tion by macrophages; this may support rapid tumour growth, Extranodal lymphomas showed virtually the same matrix patterns as their nodal cou nterparts, suggesting that (malignant) lymphoid cells generate (at lea st partly) their own specific microenvironment, In reactive lymphoid t issue beta 1 integrins were mainly found on resident cells and except for alpha 4, alpha 5 (and beta 1) the lymphoid cells expressed very li ttle, if any, pi integrins, In comparison, expression of these integri ns on lymphoma cells was reduced (follicular lymphomas) or could not b e detected at all (diffusely growing lymphomas); this might contribute to the growth pattern and metastatic properties of the tumours.