Analysis of Amyloid in Medullary Thyroid Carcinoma by Mass Spectrometry-Based Proteomic Analysis

Carcinoma showing thymus-like elements (CASTLE) with amyloid deposition in the parotid gland

Carcinoma showing thymus-like elements (CASTLE) is a rare tumor that commonly occurs in the thyroid gland. Extrathyroidal CASTLE is rarer, and only 11 cases of CASTLE of major salivary glands have been reported to date. We report the first case of amyloid deposition in parotid CASTLE. A 63-year-old man presented with a slowly growing mass in the left parotid region. Computed tomography revealed an approximately 28 × 23 mm mass lesion in the left parotid gland, and squamous cell carcinoma was suspected on biopsy. The patient underwent a parotidectomy with neck dissection. Morphologically, the tumor cells were squamoid and formed nests with lymphoid infiltration. Immunohistochemically, the tumor cells exhibited immunoreactivity for CD5, CD117/c-kit and Bcl-2, p40, and CK5 but not for p16. We diagnosed the tumor as parotid CASTLE. Amyloid deposition was also observed in the primary tumor and metastatic lymph node lesions, which were immunoreactive for cytokeratin 5. Tumor cytokeratin-derived amyloid deposition may be one of characteristics of parotid CASTLE.

Survival Outcomes of Medullary Thyroid Cancer With and Without Amyloid Deposition

OBJECTIVE

Amyloid deposition within tumor stroma is a distinctive histologic feature of medullary thyroid cancer (MTC). However, its prognostic significance remains uncertain. We aimed to elucidate the impact of amyloid status on survival outcomes in a large cohort.

METHODS

The Surveillance, Epidemiology, and End Results registry was queried to identify patients diagnosed with MTC from 2000 to 2019. Patients with amyloid-positive (International Classification of Diseases for Oncology, third edition code 8345/3) and amyloid negative (International Classification of Diseases for Oncology, third edition code 8510/3) tumors were analyzed. Overall and disease-specific survival were compared between matched cohorts using Kaplan-Meier and Cox proportional hazards analyses.

RESULTS

Of the 2526 MTC patients, 511 of which were amyloid-positive and 2015 that were amyloid negative. Amyloid-positive patients displayed lower T stage (T3/4: 28% vs 85%, P < .001) and less extrathyroidal extension (11.3% vs 81.6%, P < .001). No difference in distant metastasis rate was observed between groups (14.5% vs 14.4%, P = .98). However, amyloid-positive patients showed a tendency for distal lymph node metastasis (1.2% vs 0.3%, P = .020). On univariate analysis, amyloid-positive status showed comparable overall survival times (mean 172.2 vs 177.8 months, P = .17), but a trend toward worse cancer-specific survival (hazard ratios [HR] = 1.31, 95% CI = 0.99-1.71, P = .051). After adjusting for covariates, amyloid deposition did not independently predict overall (HR = 1.15, 95% CI = 0.91-1.47, P = .25) or cancer-specific survival (HR = 1.30, 95% CI = 0.96-1.77, P = .09). Initiating therapy later than 1 month following diagnosis was associated with worse overall survival (HR = 1.25, 95% CI = 1.02-1.54, P = .029).

CONCLUSIONS

The presence of amyloid in MTC paradoxically associates with lower T stage yet exhibits a trend toward worse cancer-specific mortality. Amyloid deposition alone does not independently influence prognosis. Delayed treatment adversely impacted overall survival.

Prognostic value of LODDS in medullary thyroid carcinoma based on competing risk model and propensity score matching analysis

Log odds of positive lymph nodes (LODDS) is an independent prognostic factor for patients with medullary thyroid carcinoma (MTC). However, the optimal cutoff value for LODDS needs to be further confirmed, and previous studies have ignored the prevalent competing events of non-cancer deaths among patients with MTC, thus possibly overestimating the risk of death from cancer. The information of patients with MTC who underwent total thyroidectomy was collected from SEER database. Restricted cubic splines (RCS) were used to determine the optimal cutoff for LODDS. Moreover, patients' overall survival (OS) and disease-specific survival (DSS) were determined using Kaplan-Meier and Cox proportional-hazards model. The competing risk models (CRM) were used to reduce the effect of competing events, and propensity score matching was performed to balance the confounding factors between groups. The cutoff value of LODDS determined by RCS was - 1.004, and a total of 2314 patients with MTC were recruited. In the CRM after PSM, factors such as age over 55 years at diagnosis, being male, treatment with chemotherapy or radiotherapy, unknown tumor size, and LODDS > - 1.004 were significantly associated with poor prognosis of patients both in univariate and multivariate analyses, while the presence of multifocal tumor indicated better prognosis. Patients with MTC who were over 55 years old at diagnosis, were male, received chemotherapy or radiation, had an unclear initial tumor size, and had LODDS > - 1.004 had a worse prognosis than patients with multifocal tumor.

Somatostatin-derived amyloidosis: a novel type of amyloidosis associated with well-differentiated somatostatin-producing neuroendocrine tumours

OBJECTIVE

To report the clinicopathologic and proteomic characteristics of a novel form of amyloidosis derived from the precursor protein somatostatin.

MATERIALS AND METHODS

Cases were identified by searching the Mayo Clinic amyloid liquid chromatography and tandem mass spectrometry (LC-MS/MS) typing database from 1 January 2008 to 1 September 2020 for specimens with the amyloid signature proteins and abundant somatostatin, in the absence of other amyloid precursor proteins. All available medical records and pathologic materials were examined.

RESULTS

Somatostatin-derived amyloid deposits were found in four patients, two females and two males, with a median age of 61.5 years (range 47-73 years). One patient also had neurofibromatosis-1. The amyloid in each case was associated with a well-differentiated, somatostatin-producing neuroendocrine tumour arising in the small bowel or pancreas. The amyloid deposits were Congo Red-positive and were readily identified by LC- MS/MS analysis. Somatostatin was present exclusively in somatostatin-associated amyloid cases (p < .001), compared to small bowel and pancreas amyloidosis cases of other types. Long-term follow-up is available for one patient who is alive 6 years after initial presentation.

CONCLUSION

We propose that somatostatin-related amyloidosis is a novel localised human amyloid type that arises in association with well-differentiated somatostatin-producing enteropancreatic neuroendocrine tumours. Treatment of the associated neuroendocrine tumour may be adequate therapy for these patients.

Overview of the 2022 WHO Classification of Familial Endocrine Tumor Syndromes

This review of the familial tumor syndromes involving the endocrine organs is focused on discussing the main updates on the upcoming fifth edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. This review emphasizes updates on histopathological and molecular genetics aspects of the most important syndromes involving the endocrine organs. We describe the newly defined Familial Cancer Syndromes as MAFA-related, MEN4, and MEN5 as well as the newly reported pathological findings in DICER1 syndrome. We also describe the updates done at the new WHO on the syndromic and non-syndromic familial thyroid diseases. We emphasize the problem of diagnostic criteria, mention the new genes that are possibly involved in this group, and at the same time, touching upon the role of some immunohistochemical studies that could support the diagnosis of some of these conditions. As pathologists play an important role in identifying tumors within a familial cancer syndrome, we highlight the most important clues for raising the suspicious of a syndrome. Finally, we highlight the challenges in defining these entities as well as determining their clinical outcome in comparison with sporadic tumors. Instead of the usual subject review, we present the highlights of the updates on familial cancer syndromes by answering select questions relevant to practicing pathologists.

Current status of the prognostic molecular markers in medullary thyroid carcinoma

Medullary thyroid cancer (MTC) is a rare thyroid malignancy, which arises from parafollicular C-cells. It occurs in the hereditary or sporadic form. Hereditary type is a consequence of activation of the RET proto-oncogene by germline mutations, whereas about 80% of sporadic MTC tumors harbor somatic, mainly RET or rarely RAS mutations. According to the current ATA guidelines, a postoperative MTC risk stratification and long-term follow-up are mainly based on histopathological data, including tumor stage, the presence of lymph node and/or distant metastases (TNM classification), and serum concentration of two biomarkers: calcitonin (Ctn) and carcinoembryonic antigen (CEA). The type of RET germline mutation also correlates with MTC clinical characteristics. The most common and the best known RET mutation in sporadic MTC, localized at codon 918, is related to a more aggressive MTC course and poorer survival. However, even if histopathological or clinical features allow to predict a long-term prognosis, they are not sufficient to select the patients showing aggressive MTC courses requiring immediate treatment or those, who are refractory to different therapeutic methods. Besides the RET gene mutations, there are currently no other reliable molecular prognostic markers. This review summarizes the present data of genomic investigation on molecular prognostic factors in medullary thyroid cancer.

Amyloids and their untapped potential as hydrogelators

Amyloid fibrils are cross-β-sheet-rich fibrous aggregates. They were originally identified as disease-associated protein/peptide deposits. The cross-β motif was consequently labelled as an alien and pathogenic fold. Subsequent research revealed that the fibrillar aggregates were benign, and the cytotoxicity in the amyloid diseases was attributed to the pre-fibrillar structures. Research in the past two decades has identified the native functional amyloids in organisms ranging from bacteria to human. The amyloid-like fibrils, therefore, are not necessarily pathogenic, and the cross-β motif is very much native. This premise makes way for the amyloids to be used as biocompatible materials. Many naturally occurring amyloidogenic proteins/peptides or their fragments have been reported in the literature to form hydrogels. Hydrogels constitute one of the most interesting classes of soft materials that find application in diverse fields such as environmental, electronic, and biomedical engineering. Applications of hydrogels in medicine are particularly extensive. Among various classes of peptides that form hydrogels, the potential of amyloids is largely untapped. In this review, we have attempted to compile the literature on amyloid hydrogels and discuss their potential applications.

Dissolution of a fibrous peptide by terahertz free electron laser

Fibrous peptides such as amyloid fibrils have various roles in biological system, e.g., as causal factor of serious amyloidosis in human and as functional regulator of cell formation in bacteria and eukaryotes. In addition, the fiber-type format is promising as biocompatible scaffold. Therefore, the dissolution method of peptide fibril is potentially useful at many scenes in medical and material fields: as reductive way of pathogenic amyloid, as modification technique of cell structure, and as fabrication tool of biomaterials. However, the fibril structure is generally difficult to be dissociated due to its rigid stacked conformation. Here, we propose a physical engineering technology using terahertz free electron laser (FEL) at far-infrared wavelengths from 70 to 80 μm. Infrared microscopy analysis of the irradiated fibril of calcitonin peptide as a model showed that β-sheet was decreased, and α-helix, turn, and others were increased, compared to those of the fibril before the FEL irradiation. Interestingly, the dissociative effect by the far-infrared laser was remarkable than that by the mid-infrared laser tuned to 6.1 μm that corresponds to amide I. In addition, simple heating at 363 K deformed the fibril state but increased the amount of β-sheet, which was contrast with the action by the FEL, and scanning-electron microscopy and Congo-red staining revealed that the fibril was collapsed power-dependently within a range from 25 to 900 mJ energies supplied with the FEL at 74 μm. It can be considered that irradiation of intense terahertz wave can dissociate fibrous conformation of peptide with little influence of thermal effect.

Amyloid and hyaline globules in undifferentiated nasopharyngeal carcinoma

We characterize the clinicopathological features of two patients (one 38 year old woman and one 42 year old man, both of Chinese ethnicity) with Epstein Barr Virus positive non-keratinizing nasopharyngeal carcinoma from an endemic region with prominent presence of amyloid and one case with both amyloid and abundant intracytoplasmic hyaline globules. The amyloid material was positive for Congo red and showed apple green birefringence when examined under polarized light. The amyloid was immunoreactive for cytokeratins and was located both intra- and extracellularly. Frequently the amyloid had a light microscopical spherical appearance and displayed peripheral radiating fibrils from a central homogenous core. One of the patients had a unique presentation of nasopharyngeal carcinoma with perceived hemoptysis and coughing up two pieces of tumor tissue. In reality, the nasopharyngeal tumor was polypoid and the two fragments were pinched of from the main tumor mass.

Proteomic study on neurite responses to oxidative stress: search for differentially expressed proteins in isolated neurites of N1E-115 cells

Reactive oxygen species attack several living organs and induce cell death. Previously, we found axonal/dendrite degeneration before the induction of cell death in hydrogen peroxide-treated neuroblastoma: N1E-115 cells and primary neurons. This phenomenon may be connected with membrane oxidation, microtubule destabilization and disruption of intracellular calcium homeostasis. However, its detailed mechanisms are not fully understood. Here, we identified proteins after treatment with hydrogen peroxide using isolated neurites by liquid chromatography-matrix-assisted laser desorption/ionization-time of flight/time of flight analysis. Twenty-one proteins were increased after treatment with hydrogen peroxide. Specifically, 5 proteins which were secretogranin-1, heat shock protein family D member 1, Brain acid soluble protein 1, heat shock 70-kDa protein 5 and superoxide dismutase 1, were identified of all experiments and increased in isolated neurites of hydrogen peroxide-treated cells compared to the controls. Furthermore, secretogranin-1 and heat shock protein family D member 1 protein expressions were significantly increased in normal aged and Alzheimer’s transgenic mice brains. These results indicate that secretogranin-1 and heat shock protein family D member 1 might contribute to reactive oxygen species-induced neurite degeneration. Both proteins have been related to neurodegenerative disorders, so their study may shed light on neurite dysfunction.

Quantitative Proteomics Analysis of Sporadic Medullary Thyroid Cancer Reveals FN1 as a Potential Novel Candidate Prognostic Biomarker

BACKGROUND

Sporadic medullary thyroid cancer (MTC) is a rare neuroendocrine tumor. Currently, although the diagnosis of sporadic MTC is relatively simple, the need to discover novel candidate prognostic biomarkers for sporadic MTC and investigate the underlying mechanism involved in this rare disease is urgent.

MATERIALS AND METHODS

We employed tandem mass tag-based liquid chromatography-mass spectrometry to identify and analyze differentially expressed proteins (DEPs) in sporadic MTC. Western blotting was used to validate the DEPs. Immunohistochemistry was performed to investigate FN1 and RPS6KA3 in an independent set of sporadic MTC tissues. Immunohistochemical data were analyzed by different statistical methods.

RESULTS

Three hundred eighty-eight DEPs were identified in mass spectrometry, mainly involved in the extracellular matrix, cytoskeletal remodeling, or oxidoreductase activity. Among them, THBS1, MMP9, FN1, RPS6KA3, SYT1, and carcinoembryonic antigen were successfully validated by Western blot. In addition, FN1 and RPS6KA3, enriched in extracellular matrix (ECM) remodeling and the mitogen-activated protein kinase (MAPK) signaling pathway, respectively, were investigated in an independent set of sporadic MTC tissues. Receiver-operator characteristic curve analysis showed that FN1 and RPS6KA3 can be used for discriminating sporadic MTC tumorous tissues from paired normal thyroid tissues, and the clinical biomarker calcitonin was positively correlated with FN1 and RPS6KA3 in tumorous tissues. Furthermore, the immunohistochemical scores of FN1 in tumorous tissue showed an inverse relationship with tumor classification, lymph node classification, and American Joint Committee on Cancer stage. Through univariate and multivariate analysis for progression-free survival, we also found that low FN1 expression in tumorous tissues was an independent worse prognostic factor for progression-free survival.

CONCLUSION

We identified that the pathophysiology of sporadic MTC involve numerous pathways, including the synaptic vesicle pathway, the MAPK signaling pathway, and the ECM remodeling pathway. Furthermore, our study also identified FN1 as novel prognostic biomarkers related to the pathophysiologic changes in sporadic MTC.

IMPLICATIONS FOR PRACTICE

Proteomic dissection and prognostic biomarkers are scarce in sporadic medullary thyroid cancer (MTC). This article reports the use of proteomics technology to comprehensively investigate the molecular mechanisms of sporadic MTC, which resulted in the identification of FN1 as a novel candidate prognostic biomarker.

Molecular signatures of medullary thyroid carcinoma by matrix-assisted laser desorption/ionisation mass spectrometry imaging

The main aim of the study was to assess the feasibility of matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI) in the pathological investigation of Medullary Thyroid Carcinoma (MTC). Formalin-fixed paraffin-embedded (FFPE) samples from seven MTC patients were analysed by MALDI-MSI in order to detect proteomic alterations within tumour lesions and to define the molecular profiles of specific findings, such as amyloid deposition and C cell hyperplasia (CCH). nLC-ESI MS/MS was employed for the identification of amyloid components and to select alternative proteomic markers of MTC pathogenesis. Results highlighted the potential of MALDI-MSI to confirm the classic immunohistochemical methods employed for the diagnosis of MTC, with good sensitivity and specificity. Intratumoural amyloid components were also detected and identified, and were characterised by calcitonin, apolipoprotein E, apolipoprotein IV, and vitronectin. The tryptic peptide profiles representative of MTC and CCH were distinctly different, with four alternative markers for MTC being detected; K1C18, and three histones (H2A, H3C, and H4). Finally, a further 115 proteins were identified through the nLC-ESI-MS/MS analysis alone, with moesin, veriscan, and lumican being selected due to their potential involvement in MTC pathogenesis. This approach represents a complimentary strategy that could be employed to detect new proteomic markers of MTC. STATEMENT OF SIGNIFICANCE: Medullary thyroid carcinoma (MTC) is a rare endocrine malignancy that originates from the parafollicular C-cells of the thyroid. The diagnosis is typically established using a combination of fine-needle aspiration biopsy (FNAB) of a suspicious nodule along with the demonstrable elevation of serum biomarkers, such as calcitonin and carcinoembryonic antigen (CEA). Unfortunately, this combination is often associated with a high degree of false-positive results and this can lead to misdiagnosis and avoidable total thyroidectomy. The current study presents the potential role of MALDI-MSI in the search for new proteomic markers of MTC with diagnostic and prognostic significance. MALDI-MSI was capable of detecting the classic immunohistochemical markers employed for the diagnosis of MTC, with good sensitivity and specificity. Furthermore, the complementary combination of MALDI-MSI and nLC-ESI-MS/MS analysis, using a single tissue section, enabled further potential markers to be identified and their spatial localisation visualised within tumoural regions. Such findings could be a valuable starting point for further studies focused on confirming the data presented here using thyroid FNABs, with the final objective being to provide complimentary assistance for the detection of MTC during the pre-operative phase.

Concurrent thoracic mesothelioma and thyroid C-cell adenoma with amyloid deposition in an aged horse

A 21‐year‐old American Saddlebred mare died with a history of weight loss and breathing difficulties of 1 month duration. Post‐mortem examination revealed a copious pleural effusion with multifocal to coalescing numerous white to grey nodular masses on the serosal surface of the pericardium, lungs and thoracic cavity. In addition, the left thyroid gland was markedly enlarged. A thoracic mesothelioma and C‐cell adenoma with amyloid deposits of the left thyroid gland were diagnosed by histopathology and confirmed by immunohistochemistry employing antibodies against cytokeratin (CK), vimentin and calcitonin. Amyloid deposits in the thyroid tumour were confirmed by Congo red staining with apple‐green birefringence under polarized light. Mesothelioma remains an uncommon neoplasm encountered in aged horses. Discussion includes the diagnostic challenge of differentiating carcinomatosis from mesothelioma by histology and differentiating reactive and neoplastic mesothelial cells by cytology.

Kidney Involvement in Systemic Calcitonin Amyloidosis Associated With Medullary Thyroid Carcinoma

A 52-year-old woman with widely disseminated medullary thyroid carcinoma developed nephrotic syndrome and slowly decreasing kidney function. A kidney biopsy was performed to differentiate between malignancy-associated membranous glomerulopathy and tyrosine kinase inhibitor-induced focal segmental glomerulosclerosis. Surprisingly, the biopsy specimen revealed diffuse glomerular deposition of amyloid that was proved to be derived from the calcitonin hormone (Acal), produced by the medullary thyroid carcinoma. This amyloid was also present in an abdominal fat pad biopsy. Although local ACal deposition is a characteristic feature of medullary thyroid carcinoma, the systemic amyloidosis involving the kidney that is presented in this case report has not to our knowledge been described previously and may be the result of long-term high plasma calcitonin levels. Our case illustrates that systemic calcitonin amyloidosis should be considered in the differential diagnosis of proteinuria in patients with medullary thyroid carcinoma.

Medullary Thyroid Carcinoma: Recent Advances Including MicroRNA Expression

Medullary thyroid carcinoma (MTC) is an uncommon neuroendocrine tumor arising from the C cells in the thyroid and accounts for about 5 % of all thyroid cancers. MTC exhibits more aggressive behavior than follicular tumors, with the majority of cases presenting with lymph node metastasis. It is particularly common among patients carrying germline RET mutations with almost 100 % penetrance. Because activating RET mutations occur in over 90 % of hereditary and 40 % of sporadic MTC, clinical trials of several RET-targeting multikinase inhibitors (MKIs) have resulted in FDA approval of vandetanib and cabozantinib for the treatment of MTC. Nevertheless, in light of significant individual differences in tumor behavior and treatment responses, there has been a persistent need for research efforts to decipher the molecular events within RET-driven or non-RET-driven tumors. Recently, the gene regulatory roles of microRNAs (miRNAs) in MTC have been studied extensively. Multiple miRNA deregulations have been discovered in MTC with potential prognostic and therapeutic implications. This review provides an overview of the basic pathology of MTC and an update on recent investigational progress.

Systemic amyloidoses and proteomics: The state of the art

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Proteomics is an established approach for diagnostic amyloid typing.

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Mass spectrometry-based methods to analyze amyloid precursors have been developed.

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Proteomic studies are ongoing to identify novel biomarkers and clarify disease mechanisms.

Systemic amyloidoses are caused by misfolding-prone proteins that polymerize in tissues, causing organ dysfunction. Since proteins are etiological agents of these diseases, proteomics was soon recognized as a privileged instrument for their investigation. Mass spectrometry-based proteomics has acquired a fundamental role in management of systemic amyloidoses, being now considered a gold standard approach for amyloid typing. In parallel, approaches for analyzing circulating amyloid precursors have been developed. Moreover, differential and functional proteomics hold promise for identifying novel biomarkers and clarifying disease mechanisms. This review discusses recent proteomics achievements in systemic amyloidoses, providing a perspective on its present and future applications.