Clinicopathologic study of E-cadherin/beta-catenin complex, and topoisomerase-II in a series of 71 liposarcoma cases

To investigate the expression of E-cadherin, beta-catenin and topoisomerase-II alpha and examine their clinical relevance in liposarcomas. The expression of E-cadherin, beta-catenin and topoisomerase II alpha was examined immunohistochemically on formalin-fixed paraffin-embedded tissue specimens from 71 patients who underwent surgical treatment for liposarcomas of the extremities or the retroperitoneum in two major cancer reference centres between 1990 and 2000. Detailed medical notes were available for all patients who were followed for median 82 months (range 5 to 215 months). Obtained expression data were weighted against clinical and pathology parameters of clinical relevance. Patients were mostly male (59%), median age was 56 years for the liposarcomas of the extremities and 60 years for the retroperitoneal liposarcomas. The tumours were of diverse histology, grade and size (median diameters 7 and 17 cm for tumours of the extremities and retroperitoneum respectively). Expression of β-catenin protein was weakly detected in 15 cases (21.1%). Similarly weak expression of topoisomerase II-alpha was detected in 14 (19.7%) cases of which only two had more than 20% of tumor cells stained positive. E-cadherin was not detected in the studied cohort of liposarcomas. We did not detect associations between the expression of the above proteins by liposarcoma cells and clinical outcome. Liposarcomas do not express E-cadherin, which matches the absence of epithelioid differentiation in this sarcoma subtype, and have low topoisomerase II-alpha expression, which justifies to some extend their resistance to anthracycline-based chemotherapy.