Reduced CD44 standard expression is associated with tumour recurrence and unfavourable outcome in differentiated thyroid carcinoma

CD44 was detected with an antibody recognizing all forms of CD44 (CD44 stan dard) and others specific for its v3 and v6 variant isoforms; their prognos tic value was evaluated in 213 patients with differentiated thyroid carcino ma (DTC). The staining patterns of CD44 standard (s) and CD44v6 in tumour t issue were quite similar, 176 cases (83%) being highly positive for CD44s a nd 153 cases (72%) for CD44v6. Only 18 (9%) tumours showed high expression of CD44v3. Papillary carcinomas were significantly more often high expresso rs of CD44s and CD44v6 than follicular carcinomas (p<0.001 for both). Age o lder than 60 years, distant metastases, and advanced pTNM stage were relate d to loss of expression of CD44s (p<0.001, p = 0.021, and p = 0.003, respec tively). Tumour recurrence and cancer-related mortality were related to the reduced level of CD44s (p = 0.049 and p = 0.042). CD44v3 did not associate with any of the clinicopathological factors. In univariate analysis, CD44s was the only significant prognostic factor for disease-free survival (p = 0.0488). In multivariate analysis, CD44s and thyroglobulin level were signi ficant prognostic factors for disease-free survival (p = 0.040 and p<0.001, respectively). The reduced level of CD44s in DTC patients seems to be an i ndependent prognostic factor for unfavourable disease outcome. Copyright (C ) 2000 John Wiley & Sons, Ltd.