Immunohistochemical detection of E-cadherin in differentiated thyroid carcinomas correlates with clinical outcome.

A retrospective immunohistochemical analysis of the adhesion molecule E-cadherin (E-CD) was performed in 112 differentiated thyroid carcinomas and 38 synchronous and 20 relapse metastases primarily from operations performed at the Medical School Hanover between 1982 and 1992. E-CD-specific antibody 5H9 was applied to paraffin-embedded tissues. All patients were clinically followed for a maximal period of 12 years. Lack of E-CD expression i.e., <5% of tumor cells positive) occurred in 18 of 112 (16.1%) cases, whereas the majority showed either low (24.1%), medium (35.7%), or high (24.1%) positivity. No difference was found between papillary (n = 88) and follicular (n = 24) carcinomas. Univariate statistical analysis for survival (Kaplan-Meier) showed that lack of E-CD expression (P < 0.024) is an adverse prognostic factor for differentiated thyroid carcinomas. The highest significance was seen among patients without lymph node involvement at first presentation (pN(0); P = 0.0068) and among females (P = 0.0033). Multivariate analysis (Cox model) indicated that E-CD staining is an independent prognostic factor (corrected risk factor, 3.7; P < 0.03) in addition to distant metastasis (pM1) and tumor size. A comparison of E-CD stainings between primary tumors and their metastatic lesions showed similar results in both synchronous and relapse metastases after therapy. In conclusion, E-CD immunostaining is an independent prognostic indicator for differentiated thyroid carcinomas. It may help to uncover the small group of patients with differentiated thyroid carcinomas carrying a high risk of suffering an unfavorable clinical outcome.