title: Mcm-2 and Ki-67 have limited potential in preoperative diagnosis of thyroid malignancy.
abstract: OBJECTIVE
  Minichromosome maintenance protein 2 (Mcm-2) is essential for DNA replication and serves as a useful biomarker of cell-cycle state in human tissue samples. Ki-67 is an established proliferation marker. Because Mcm-2 expression has not previously been assessed in thyroid tissue, the aim of this study was to assess the expression of both proteins in a range of thyroid lesions to determine their potential value as preoperative markers of thyroid malignancy.
  
  
  METHODS
  Mcm-2 and Ki-67 protein expression were assessed by immunohistochemistry in formalin-fixed, paraffin-embedded thyroid tissues from 128 patients with histologic diagnoses of papillary carcinoma (n = 38), follicular carcinoma (n = 22), follicular adenoma (n = 33), and dominant nodules of multinodular goitre (n = 35).
  
  
  RESULTS
  Mcm-2 and Ki-67-labeling indices (LIs) were both higher in follicular and papillary carcinomas than in follicular adenomas or dominant nodules. The Ki-67 LI discriminated better between follicular carcinomas and follicular adenomas (P < .0001) than Mcm-2 (P = .0273). However, the Mcm-2 and Ki-67 LIs overlapped widely between the four histologic groups, and the expression of these proteins was also noted to be heterogenous within these lesions.
  
  
  CONCLUSIONS
  Neither Mcm-2 or Ki-67 can currently be reliably applied as preoperative markers to distinguish benign from malignant thyroid lesions.
authors.affiliation: School of Surgical and Reproductive Sciences, Department of Cellular Pathology, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom.
authors.forename: Pallavi
authors.initials: P
authors.lastname: Mehrotra
authors.forename: Michael A
authors.initials: MA
authors.lastname: Gonzalez
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Johnson
authors.forename: Nick
authors.initials: N
authors.lastname: Coleman
authors.forename: Janet A
authors.initials: JA
authors.lastname: Wilson
authors.forename: Barry R
authors.initials: BR
authors.lastname: Davies
authors.forename: Tom W J
authors.initials: TW
authors.lastname: Lennard
mesh_terms: D000236:Adenoma / Q000175:diagnosis; D014408:Biomarkers, Tumor / Q000032:analysis*; D002291:Carcinoma, Papillary / Q000175:diagnosis; D018797:Cell Cycle Proteins / Q000032:analysis*; D006044:Goiter, Nodular / Q000175:diagnosis; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis*; D064111:Minichromosome Maintenance Complex Component 2; D009687:Nuclear Proteins / Q000032:analysis*; D013961:Thyroid Gland / Q000737:chemistry; D013964:Thyroid Neoplasms / Q000175:diagnosis*
chemical_list: D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D019394:Ki-67 Antigen; D009687:Nuclear Proteins; C084859:MCM2 protein, human; D064111:Minichromosome Maintenance Complex Component 2