Sporadic Parathyroid Adenoma: A Pilot Study of Novel Biomarkers in Females

Abstract

Background and Objectives: Parathyroid adenoma is a distinct cause of primary hyperparathyroidism, with the vast majority being sporadic ones. Proteomic analysis of parathyroid adenomas has proposed a large number of related proteins. The aim of this study is to evaluate the immunohistochemical staining of ANXA2, MED12, MAPK1 and VDR in parathyroid adenoma tissue. Materials and Methods: Fifty-one parathyroid adenomas were analyzed for ANXA2, MED12, MAPK1 and VDR expressions. Tissue was extracted from formalin-fixed paraffin-embedded parathyroid adenoma specimens; an immunohistochemical study was applied, and the percentage of allocation and intensity were evaluated. Results: ANXA2 stained positively in 60.8% of all cell types, while MED12 had positive staining in 66%. MAPK1 expression was found to be negative in total, although a specific pattern for oxyphil cells was observed, as they stained positive in 17.7%. Finally, VDR staining was positive at 22.8%, based on nuclear staining. Conclusions: These immunohistochemical results could be utilized as biomarkers for the diagnosis of sporadic parathyroid adenoma. It is of great importance that a distinct immunophenotype of nodule-forming cells in a positive adenoma could suggest a specific pattern of adenoma development, as in hereditary patterns.

Keywords: ANXA2; MAPK1; MED12; VDR; immunohistochemistry; parathyroid adenoma.

Figure 1

ANXA2 immunohistochemical staining: (a) negative staining of chief cells and positive staining of normal parathyroid tissue; (b) positive staining of chief cells; (c) positive staining of clear cells; (d) a distinct immunophenotype of chief cell nodule in an adenoma.

Figure 2

MED12 immunohistochemical staining: (a) positivity in normal parathyroid tissue, (b) a distinct immunophenotype of oxyphil cell nodule in a positive chief cell adenoma; (c) positive chief cells (blue arrow), clear cells (red arrow) and oxyphil cells (green arrow).

Figure 3

MAPK1 immunohistochemical staining: (a) positive oxyphil cells and negative chief cells; (b) negative chief cells.

Figure 4

VDR immunohistochemical staining: (a) positive nuclear staining in chief (green arrow) and clear (red arrow) cells; (b) negative (blue) and positive (brown) nuclear staining in chief cells.

Figure 5

VDR immunohistochemical staining: (a) positive membranous staining in the apical side of chief cells; (b) positive, intense cytoplasmic staining in group of chief cells (green circle) encircled by positive moderate cytoplasmic staining; (c) a distinct immunophenotype of chief cell nodule with mild intensity in an intense positive chief cell adenoma; (d) intense positive membranous staining in group of chief cells (red circle) encircled by mild positive membranous staining chief cells.