title: CD56, HBME-1 and cytokeratin 19 expressions in papillary thyroid carcinoma and nodular thyroid lesions.
abstract: BACKGROUND
  Carcinomas of the thyroid follicular epithelium are the most common cancers of the endocrine system. In the diagnosis of thyroid nodules and tumors, the gold standard is histological evaluation. In cases which have morphological overlap, immunohistochemistry is needed for differential diagnosis. The purpose of this study is to investigate the expressions of CD56, HBME-1, cytokeratin 19 (CK19) antibodies in papillary thyroid carcinoma (PTC) and thyroid nodular lesions and their contributions to differential diagnosis.
  
  
  METHODS
  In this study, 47 PTCs (26 follicular variant, 21 classic type) and 26 benign thyroid lesions (15 nodular hyperplasia, 10 follicular adenomas, 1 Hurtle cell adenoma) were analyzed retrospectively. HBME-1, CK19, and CD56 antibodies were performed with immunohistochemical methods. The results were evaluated statistically.
  
  
  RESULTS
  +3 staining with HBME-1 and CK19 was observed in 72.3% and 83% of patients with PTC. In 95.7% of PTC cases, loss of CD56 expressions in various degrees was identified. A statistically significant difference was detected in HBME-1, CK19, and CD56 expressions between PTCs and benign lesions (P< 0.001).
  
  
  CONCLUSIONS
  In our study, positive staining of HBME-1, CK19, and loosing expression of CD56 that supports malignancy was found and concluded that CD56 is a helpful antibody for the differential diagnosis of benign and malignant lesions and may increase the diagnostic accuracy when used with HBME-1 and CK19.
authors.affiliation: Department of Pathology, Erzurum Region Training and Research Hospital, Erzurum, Turkey.
authors.forename: Senay
authors.initials: S
authors.lastname: Erdogan-Durmus
authors.affiliation: Department of Pathology, Okmeydani Training and Research Hospital, İstanbul, Turkey.
authors.forename: Deniz
authors.initials: D
authors.lastname: Ozcan
authors.affiliation: Department of Pathology, Okmeydani Training and Research Hospital, İstanbul, Turkey.
authors.forename: Enver
authors.initials: E
authors.lastname: Yarikkaya
authors.affiliation: Department of Pathology, Erzurum Region Training and Research Hospital, Erzurum, Turkey.
authors.forename: Ali
authors.initials: A
authors.lastname: Kurt
authors.affiliation: Department of Internal Medicine, İstinye State Hospital, İstanbul, Turkey.
authors.forename: Aynur
authors.initials: A
authors.lastname: Arslan
keywords: CD56; HBME-1; immunohistochemistry; papillary thyroid carcinoma