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Mcm-2 and Ki-67 Have Limited Potential in Preoperative Diagnosis of Thyroid Malignancy

Authors

  • Pallavi Mehrotra BMedSci, BMBS, MRCS, MD,

    1. School of Surgical and Reproductive Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom
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  • Michael A. Gonzalez BMedSci, BMBS, MRCP, PhD,

    1. School of Surgical and Reproductive Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom
    2. Medical Research Council Cancer Cell Unit, Hutchison/MRC Research Centre, Cambridge, United Kingdom
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  • Sarah J. Johnson MBBS, PhD, FRCPath,

    Corresponding author
    1. Department of Cellular Pathology, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom.
    • S. J. Johnson, MBBS, PhD, FRCPath, Consultant Pathologist, Department of Cellular Pathology, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, United Kingdom.
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  • Nick Coleman MBBS, PhD, MRCPath,

    1. Medical Research Council Cancer Cell Unit, Hutchison/MRC Research Centre, Cambridge, United Kingdom
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  • Janet A. Wilson BSc, MBChB, FRCEd, FRCEng, MD,

    1. School of Surgical and Reproductive Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom
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  • Barry R. Davies BSc, PhD,

    1. School of Surgical and Reproductive Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom
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  • Tom W. J. Lennard MBBS, FRCS, MD

    1. School of Surgical and Reproductive Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom
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  • This work was supported by a Royal College of Surgeons of England and British Association of Endocrine Surgeons fellowship to P.M.

Abstract

Objectives: 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.

Conclusion: Neither Mcm-2 or Ki-67 can currently be reliably applied as preoperative markers to distinguish benign from malignant thyroid lesions.

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