Immunohistochemical study of ceruloplasmin, lactoferrin and secretory component expression in neoplastic and non-neoplastic thyroid gland diseases

The expression of lactoferrin (LF), ceruloplasmin (CP) and secretory compon ent (SC) in various thyroid diseases was investigated using an immunohistoc hemical method. LF is an iron-binding protein overexpressed in certain huma n adenocarcinomas. CP is implicated in carcinogenesis and SC is part of the local immune defense system. Sections of 15 follicular adenomas, 5 follicu lar carcinomas (FC), 16 papillary carcinomas (PC), 15 goitres and 2 cases o f lymphocytic thyroiditis were re-examined and investigated immunohistologi cally by a streptavidin-biotin method. A positive immunostain reaction for CP and LF was observed in ail cases of PC and FC. A positive immunostain re action for SC was observed in 13/16 cases of PC and 4/5 cases of FC. A nega tive immunostain reaction for CP, LF and SC was observed in medullary cance rs, in follicular adenomas and in the cases with goitre. We conclude that t he immunostain expression of LF, CP and SC is a valuable diagnostic aid in the differential diagnosis between benign and malignant thyroid tumors. The expression of SC indicates the presence of a local immunodefensive system.