ADHESION MOLECULES IN HIGH-GRADE SOFT-TISSUE SARCOMAS - CORRELATION TO CLINICAL OUTCOME

The extracellular matrix (ECM) forms a framework for cell adhesion, bu t it also regulates growth and differentiation. Normal and malignant c ells interact with the ECM via specific receptors, the integrins. To e xplore the mechanisms of growth and spread in soft tissue sarcomas the expression of the major ECM molecules and their corresponding integri n receptors were studied by immunohistochemistry in high-grade soft ti ssue sarcomas: malignant fibrous histiocytoma (20 cases), malignant pe ripheral nerve sheath tumour (17 cases) and synovial sarcoma (21 cases ). The expression pattern was compared with cell proliferation and cli nical outcome. Integrins were found to be expressed according to histo logical pattern. In synovial sarcomas, the epithelial component showed a high alpha(2) but negative or minimal detection of alpha(5) express ion, while a weak alpha(2) expression and a moderate alpha(5) expressi on were found in the spindle cell component. No alpha(2) expression wa s detected in malignant fibrous histiocytoma, and minimal alpha(5) exp ression was detected in malignant schwannoma. The alpha(6) expression levels were positively correlated with the occurrence of metastases in all types of sarcomas studied. The expression of ECM molecules was do wnregulated and irregular in most tumours. In conclusion, the divergen t integrin expression pattern could be useful in the diagnosis and cla ssification of soft tissue sarcomas. Furthermore, since high laminin r eceptor expression correlates with occurrence of metastases, it could become a useful prognostic marker. (C) 1998 Elsevier Science Ltd. All rights reserved.