Loss of Raf-1 kinase inhibitor protein expression is associated with lymph node metastasis in papillary thyroid cancer.

Abstract

Raf-1 kinase inhibitor protein has potential as a molecular determinant of tumor metastasis and may serve as a prognostic marker. The aim of this study is to analyze the correlation between Raf-1 kinase inhibitor protein expression and the clinicopathologic characteristics of papillary thyroid cancer. Immunohistochemical analysis. Tertiary care teaching hospital. Fifty-nine patients with papillary thyroid cancer underwent total thyroidectomy and central neck dissection. Using specimens from total thyroidectomy and central neck dissection, we performed immunohistochemistry for Raf-1 kinase inhibitor protein and evaluated associations between Raf-1 kinase inhibitor protein expression and lymph node metastasis, tumor size, number of tumors, extrathyroidal invasion, angiolymphatic invasion, and status of the tumor border. We found significantly low Raf-1 kinase inhibitor protein expression in papillary thyroid cancer with lymph node metastasis. However, Raf-1 kinase inhibitor protein expression was not associated with tumor size, multifocality, extrathyroidal invasion, or status of the tumor border. The loss of Raf-1 kinase inhibitor protein expression is associated with lymph node metastasis of papillary thyroid cancer but not with the progression of primary tumors.