The role of S100-positive dendritic cells in the prognosis of papillary thyroid carcinoma

Dendritic cells are potent antigen-presenting cells, common in inflammatory processes. We sought to investigate dendritic cell expression in papillary thyroid carcinoma and the relationship of dendritic cell density with the extent of thyroiditis and prognosis. Specimens from 69 consecutive patients with papillary thyroid carcinoma were immunohistochemically stained for the S100 protein, and the number of positive dendritic cells was counted. Cells were sparse in normal thyroid tissue and common in areas of thyroiditis and papillary carcinoma. Dendritic cell density in papillary carcinoma correlated with the thyroiditis grade and dendritic cell density in surrounding areas of thyroiditis. High-grade thyroiditis (42% of patients) was inversely associated with 3-year recurrence. Dendritic cell density was not associated with disease-free survival. The lack of prognostic value of dendritic cell density is not compliant with the only other relevant study in the literature, and further research is required.