Quantitative proteomics analysis of sporadic parathyroid adenoma tissue samples

Vitamin D receptor: a possible biomarker for sporadic parathyroid adenoma?

Parathyroid adenoma is the main cause of primary hyperparathyroidism. The genetic basis of the disease is still unclear. Vitamin D receptor (VDR) is involved in parathormone regulation. The aim of this study is to evaluate Vitamin D receptor expression in sporadic parathyroid adenoma. Fifty-one patients with parathyroid adenoma and 51 healthy volunteers were enrolled in the study and genetic and immunohistochemical studies were conducted. VDR polymorphism TaqI was correlated with parathyroid adenoma development, while VDR stained positive in immunohistochemical study. Our study suggests VDR as a major contributor to sporadic parathyroid adenoma formation in Greek population.

Molecular basis of symptomatic sporadic primary hyperparathyroidism: New frontiers in pathogenesis

Primary hyperparathyroidism is a common endocrine disorder characterized by inappropriate elevation of parathyroid hormone and hypercalcemia. While predominantly an asymptomatic disease in Western populations, symptomatic presentations are more prevalent in Eastern countries. The molecular pathogenesis of sporadic PHPT primarily involves genetic and epigenetic alterations leading to abnormal parathyroid cell proliferation and altered calcium sensing mechanism. To date, MEN1 and cyclin D1 are the only established drivers of sporadic PHPT. Somatic MEN1 gene mutations occur in 30-40 % of sporadic parathyroid adenomas (PA), with a recent study on symptomatic cases reporting germline variants.Cyclin D1 overexpression in sporadic PA has been observed in 20-40 % of cases in Western populations and 80 % of cases in Eastern populations, with an inverse association with cyclin-dependent kinase inhibitors CDKN2A and CDKN2B expression. The calcium-sensing receptor expression was significantly lower in symptomatic compared to asymptomatic PHPT, strongly supported by epigenetic deregulation (promoter hypermethylation and histone methylation). Recent studies have highlighted the potential involvement of EZH2, a histone methyltransferase, in parathyroid tumorigenesis. Additionally, parathyroid-specific transcription factors like GCM2, PAX1, and GATA3 are emerging as putative tumor suppressors, especially from the symptomatic PHPT. Next-generation sequencing has identified novel potential drivers such as PIK3CA, MTOR, and NF1 in sporadic PC, alongside CDC73. The molecular landscape of sporadic PHPT appears to differ between Eastern and Western populations. This heterogeneity underscores the need for further large-scale studies, particularly in symptomatic cases from developing nations, to comprehensively elucidate the molecular drivers of parathyroid tumorigenesis.

Pilot Study of Plasma miRNA Signature Panel for Differentiating Single vs Multiglandular Parathyroid Disease

CONTEXT

The ability to differentiate sporadic primary hyperparathyroidism (sPHPT) caused by a single parathyroid adenoma (PTA) from multiglandular parathyroid disease (MGD) preoperatively, as well as definitely diagnose sPHPT in difficult patients, would enhance surgical decision-making.

OBJECTIVE

This work aimed to identify miRNA (miR) signatures for MGD, single- and double-PTA, as well as cell-free miRNA (cfmiR) in plasma samples from patients with single-PTAs to use as biomarkers.

METHODS

A total of 47 patients with sPHPT (single-PTA n = 32, double-PTA n = 12, MGD n = 9). Preoperative plasma samples from 16 single-PTA and 29 normal healthy donors (NHDs). All specimens were processed and analyzed for 2083 miRs using HTG EdgeSeq miR whole-transcriptome assay and normalized using DESeq2 to identify differentially expressed (DE) miRs. MiR classifiers were identified using Random Forest. Main outcome measures were receiver operating characteristic curves and areas under the curve.

RESULTS

MiR signatures distinguished normal parathyroid from MGD and PTA as well as MGD from PTA in tissue samples. Common miRs were found in the single-PTA and double-PTAs. Data integration identified a 27-miR signature in single-PTA tissue samples compared to the rest of the tissue samples. In plasma samples analysis, significant cfmiRs were DE in single-PTA patients compared to NHD. Of those, only 9 miRNAs/cfmiRs were found DE both in tissue and plasma samples from patients diagnosed with a single PTA (AUC = 76%).

CONCLUSION

Twenty-seven miRs were consistently found DE in single-PTA tissue and plasma samples. Data integration showed a 9-cfmiR signature with potential clinical utility to preoperatively diagnose sPHPT caused by a single PTA, which could decrease more invasive parathyroid explorations.

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

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.

Sporadic parathyroid adenoma: an updated review of molecular genetics

Introduction

Primary HPT (PHPT) is a common disorder, affecting approximately 1% of the general population. Parathyroid adenomas emerge as non-familial sporadic in 90% of cases. The aim of this review is to give a detailed update of molecular genetics of sporadic parathyroid adenoma reported in international literature.

Methods

A bibliographic research was conducted in PubMed, Google Scholar, and Scopus.

Results

Seventy-eight articles were included in our review. CaSR, MEN1, CCND1/PRAD, CDKI, angiogenic factors like VEGF, FGF, TGFβ, and IGF1, and apoptotic factors are important genes in parathyroid adenomas pathogenesis that have been established by several studies. A huge list of proteins is differently expressed in parathyroid adenomas measured by Western Blotting, MALDI/TOF, MS spectrometry, and immunohistochemistry. These proteins take part in several cell processes such as cell metabolism, cytoskeleton structural stability, cell oxidative stress regulation, cell death, transcription, translation, cell connection, and cell signaling transmission, while they can be found over- or underexpressed in abnormal tissues.

Conclusion

This review gives a detailed analysis of all reported data on genomics and proteomics of parathyroid adenoma. Further studies should be applied on understanding parathyroid adenoma pathogenesis and introducing new biomarkers for early detection of primary hyperparathyroidism.

Hormones Secretion and Rho GTPases in Neuroendocrine Tumors

Neuroendocrine tumors (NETs) belong to a heterogeneous group of neoplasms arising from hormone secreting cells. These tumors are often associated with a dysfunction of their secretory activity. Neuroendocrine secretion occurs through calcium-regulated exocytosis, a process that is tightly controlled by Rho GTPases family members. In this review, we compiled the numerous mutations and modification of expression levels of Rho GTPases or their regulators (Rho guanine nucleotide-exchange factors and Rho GTPase-activating proteins) that have been identified in NETs. We discussed how they might regulate neuroendocrine secretion.

Dysregulated mitogen-activated protein kinase pathway mediated cell cycle disruption in sporadic parathyroid tumors

OBJECTIVES

The study was designed to evaluate expression profiling of mitogen-activated protein kinase (MAPK) signalling pathway genes in sporadic parathyroid adenoma.

METHODS

Expression of MAPK signalling pathway genes including activated transcription factors and cell cycle regulatory genes was analysed by real-time PCR- based array in parathyroid adenoma (N = 20) and normal parathyroid tissue (N = 4).

RESULTS

MAPK signalling pathway as studied by PCR array revealed that a total of 22 genes were differentially expressed (≥ twofold change, p ≤ 0.05) in parathyroid adenoma. Up-regulated genes were ARAF, MAPK12, CREBBP, MYC, HSPB1, HRAS, CDK4, CCND1, and E2F1, and down-regulated genes were MAP4K1, DLK1, MAP3K4, MAPK10, MAPK8, ATF2, SMAD4, MEF2C, LAMTOR3, FOS, CDKN2A CDKN2B, and RB1. The present study revealed that ERK1/2 signalling pathway with up-regulation of HRAS, ARAF, and MEK1 genes and up-regulation of positive regulators of cell cycle (CCND1, CDK4, and E2F1) and down-regulation negative regulators of cell cycle (CDKN2A, CDKN2B, and RB1) made highly dysregulated MAPK signalling pathway in parathyroid adenoma. Expression of CDK4 was positively associated with plasma PTH level (r = 0.60, p = 0.04) and tumor weight (r = 0.80, p = 0.02) of the adenoma patients, respectively. Expression of CDKN2A was correlated negatively with PTH level (r = - 0.52, p = 0.04) of the adenoma patients.

CONCLUSION

The current study revealed that ERK pathway and associated cell cycle regulator genes are dysregulated in sporadic parathyroid adenoma.