The prognostic significance of e-cadherin in papillary thyroid carcinoma was evaluated in a retrospective study. From September 1985 to December 1996, 113 patients underwent surgery for papillary thyroid carcinoma. Seventy-eight formalin-fixed, paraffin-embedded tissue samples were available for immunohistochemical analysis of e-cadherin expression. In 74 of these 78 patients the postoperative course is known for 2 months to 35.2 years (median 3.6 years, mean: 4.9 +/- 4.8 years). Reduced or negative e-cadherin expression (< or = 20%) was associated with advanced T categories of the primary tumours and higher rates of synchronous lymph node involvement and distant metastasis. During follow-up in this group of patients locoregional tumour recurrence occurred more frequently and survival was shorter than in patients with tumours which exhibited e-cadherin expression of > 20%. Statistical analysis revealed e-cadherin expression (< or = 20%/ > 20%), synchronous distant metastasis (M0/pM1, cM1) and radicality of resection (R0/R1, 2) as significant risk factors for survival. Our findings provide evidence that e-cadherin is a prognostic factor in papillary thyroid carcinoma.