CD44 isoform expression in synovial sarcoma correlates with epitheliogenesis but not prognosis

Aims: We immunohistochemically determined the expression of CD44 standard a nd splice variant isoforms in a series of synovial sarcomas and sought corr elations with histological subtype and clinical parameters including outcom e, Methods and results: From 39 patients, a total of 56 formalin-fixed and par affin-embedded tumour samples (including initial, recurrent and metastatic tumours) were used to immunohistochemically evaluate the expression of epit opes encoded by CD44s and the CD44 splice variants CD44v3-v10. Significance of proposed prognostic indicators was evaluated in relation to the surviva l, time to local recurrence and time to metastases using log-rank analysis. Sixty-four percent of synovial sarcomas expressed CD44s and 46% expressed CD44v3-v10 (var), Synovial sarcomas with epithelial or epithelioid areas pr eferentially expressed CD44s in these areas when compared with the spindle cell element, There were no correlations with clinical parameters or outcom e, Conclusions: The expression of CD44 was not found to correlate with surviva l, local recurrence or metastatic ability. In synovial sarcoma. CD44 and va riant isoform expression appears to be associated with the degree of epithe lial differentiation. CD44 expression in synovial sarcoma shows interesting similarities to CD44 expression in embryological epitheliogenesis.