Incidence of medullary thyroid carcinoma and Hirschsprung disease based on the cosmos database.

PURPOSE: Multiple endocrine neoplasia Type 2A (MEN2A) can occur with Hirschsprung disease (HD) due to mutation in the RET proto-oncogene, with the majority developing medullary thyroid carcinoma (MTC). Given the comorbidity, many parents have contacted us to share concerns and unfortunate experiences about the prevalence rates of MEN2A/MTC in patients with HD. The aim is to determine the prevalence rate of patients with HD and MEN2A or medullary thyroid carcinoma, respectively. METHODS: This is a cross-sectional study of the COSMOS database from January 01, 2017, to March 08, 2023. The database was searched for patients diagnosed with MEN2A, MTC, and HD. IRB exemption was provided (COMIRB #23-0526). RESULTS: The database contained 183,993,122 patients from 198 contributing organizations. The prevalence of HD and MEN2A was 0.00002%, and for HD and MTC was 0.000009%. One in 66 patients (1.5%) with MEN2A also had HD. One in 319 patients (0.3%) in the HD group had MEN2A. One in 839 patients (0.1%) within the HD population had MTC. CONCLUSION: The prevalence of MTC and HD or MEN2A and HD in the study population was low. Considering that almost all MEN2A patients have a positive family history, this data does not support the general genetic testing of HD patients.

The Changing Face of Multiple Endocrine Neoplasia 2A: From Symptom-Based to Preventative Medicine.

CONTEXT: Early genetic association studies yielded too high risk estimates for multiple endocrine neoplasia (MEN2A), suggesting a need for extended surgery. OBJECTIVE: The objective was to delineate temporal changes in MEN2A presentation by birth cohort analyses. METHODS: Birth cohort analyses (10-year increments; ≤1950 to 2011-2020) of carriers of rearranged during transfection (RET) mutations who underwent surgery for MEN2A. RESULTS: Included in this study were 604 carriers (155 index, 445 nonindex, 4 additional patients), with 237 carriers harboring high-risk mutations, 165 carriers moderate-high risk mutations, and 202 carriers low-moderate risk mutations. With increasing recency of birth cohorts, there was a continual decline in index patients from 41-74% to 0% (P < .001) and of medullary thyroid cancer (MTC) from 96-100% to 0-33% (P < .001). Node metastases diminished from 62-70% to 0% (P ≤ .001; high and low-moderate risk mutations), whereas biochemical cure after thyroidectomy surged from 17-33% to 100% (P ≤ .019; high and low-moderate mutations). Surgical interventions for MEN2A-related tumors were performed increasingly earlier, causing median carrier age to fall: from 51-63 to 3-5 years at thyroidectomy (P < .001); from 46-51 to 24-25 years at first adrenalectomy (P ≤ .013; high and moderate-high risk mutations); and from 43.5-66 to 16.5-32 years at parathyroidectomy. MTC diameters were more effectively decreased from 14-32 to 1-4 mm (P ≤ 002) than pheochromocytoma diameters (nonsignificant). CONCLUSION: These insights into MEN2A presentation, adjusted by birth year, illustrate the shift from reactive to preventative medicine, enabling less extensive risk-reducing surgery.

The protean role of Val804Met RET mutation in thyroid neoplasms: An example of a "MEN2C" syndrome?

BACKGROUND: Val804Met RET is one of the most common genetic alterations in Multiple Endocrine Neoplasia 2 and is considered to confer only a moderate risk for familial medullary thyroid carcinoma (MTC). The associated phenotype can however be much more complex in some cases. METHODS: A clinical, genetic, and pathological analysis was conducted on a family cluster of thyroid neoplasms associated with Val804Met RET mutation. RESULTS: All the kindreds who are carriers of the mutated RET received total thyroidectomy + /- VI level dissection. The proband presented with a pT1bN0 MTC, her 29-yo brother showed a concomitant papillary thyroid carcinoma (PTC) and MTC, their father had a pT1a PTC plus a follicular adenoma, while the uncle of the proband showed C-cell hyperplasia. None had clinical or biochemical evidence of parathyroid disorders or pheochromocytoma. CONCLUSIONS: In the presence of Val804Met RET several types of thyroid premalignant and malignant should be screened for, and without limiting to MTC.

Medullary thyroid cancer with RET V804M mutation: more indolent than expected?

BACKGROUND: Significant genotype-phenotype variability among multiple endocrine neoplasia type 2A patients with a RET V804M mutation has been reported. METHODS: Patients with a RET V804M mutation treated at a single center were identified (January 1996-December 2020). The baseline characteristics, operative details, pathology, biochemical, and long-term data were analyzed. RESULTS: There were 79 patients; none developed pheochromocytoma or hyperparathyroidism or died in the study period. The mean age was 41.5 years (range = 1.0-81.0 years); 46.8% were men. Of 68 surgical patients, 53 (77.9%) underwent total thyroidectomy and 15 (22.1%) underwent total thyroidectomy with central neck dissection with or without lateral neck dissection. Twenty-four patients had elevated preoperative calcitonin, of whom 12 underwent total thyroidectomy (median = 7.5; range = 5.0-237.0 pg/mL), 10 underwent total thyroidectomy + central neck dissection (median = 27.6; range = 5.1-147.0 pg/mL), and 2 underwent total thyroidectomy + central neck dissection + lateral neck dissection (median = 3182.0; range = 361.0-6003.0 pg/mL). Pathology was benign (27.9%), papillary thyroid cancer alone (1.5%), C-cell hyperplasia (23.5%), and medullary thyroid cancer (47.1%; median tumor size = 3.0 mm). Three patients had elevated calcitonin postoperatively (median follow-up time = 60.0 months). In adjusted modeling, a preoperative calcitonin >5 pg/mL was associated with having medullary thyroid cancer on final pathology (odds ratio = 13.3; 95% confidence interval, 3.2-56.3; P < .001). CONCLUSION: In this large United States cohort of surgical patients with a RET V804M mutation, most had indolent disease and were without classic multiple endocrine neoplasia type 2A features. Calcitonin >5 pg/mL may serve as a meaningful value to guide surveillance and timing of surgery.

The role of prophylactic parathyroidectomy during thyroidectomy for MTC in patients with MEN2A syndrome.

AIM: To define the role of prophylactic parathyroidectomy in the surgical treatment of medullary thyroid carcinoma (MTC) in multiple endocrine neoplasia type IIa (MEN2A) syndrome through a literature review.

Multiple endocrine neoplasia type 2 (MEN2) and RET specific modifications of the ACMG/AMP variant classification guidelines and impact on the MEN2 RET database.

The Multiple Endocrine Neoplasia type 2 (MEN2) RET proto-oncogene database, originally published in 2008, is a comprehensive repository of all publicly available RET gene variations associated with MEN2 syndromes. The variant-specific genotype/phenotype information, age of earliest reported medullary thyroid carcinoma (MTC) onset, and relevant references with a brief summary of findings are cataloged. The ACMG/AMP 2015 consensus statement on variant classification was modified specifically for MEN2 syndromes and RET variants using ClinGen sequence variant interpretation working group recommendations and ClinGen expert panel manuscripts, as well as manuscripts from the American Thyroid Association Guidelines Task Force on Medullary Thyroid Carcinoma and other MEN2 RET literature. The classifications for the 166 single unique variants in the MEN2 RET database were reanalyzed using the MEN2 RET specifically modified ACMG/AMP classification guidelines (version 1). Applying these guidelines added two new variant classifications to the database (likely benign and likely pathogenic) and resulted in clinically significant classification changes (e.g., from pathogenic to uncertain) in 15.7% (26/166) of the original variants. Of those clinically significant changes, the highest percentage of changes, 46.2% (12/26), were changes from uncertain to benign or likely benign. The modified ACMG/AMP criteria with MEN2 RET specifications will optimize and standardize RET variant classifications.

RET gene mutational diagnosis and precision medicine in Mexico.

Precision medicine is a reality in some diseases; it supports the development of accurate and specific diagnostic methods, new drugs and molecules. Our research team in Mexico, made up of clinical and biomedical researchers, has been performing free RET gene mutational diagnosis for medullary thyroid cancer and multiple endocrine neoplasia (MEN) 2 and 3 for 20 years. RET pathogenic variants in the Mexican population are consistent with reported data: most common mutations are 634/NEM2 and 918/NEM3. Currently, new nanobiotechnology methods are being developed for this type of determination in order to obtain faster, simpler, more sensitive and specific results applicable in all types of laboratories.

La medicina de precisión en algunas enfermedades es una realidad; respalda el desarrollo de métodos diagnósticos certeros y específicos, de nuevas drogas y moléculas. Nuestro equipo de investigación en México, conformado por investigadores clínicos y biomédicos, desde hace 20 años realiza de forma gratuita el diagnóstico mutacional del gen RET y su relación con el cáncer medular de tiroides y la neoplasia endocrina múltiple (NEM) 2 y 3. Las variantes patogénicas de RET en la población mexicana coinciden con los datos reportados: la mayoría con 634/NEM2 y 918/NEM3. Actualmente se están desarrollando nuevos métodos de nanobiotecnología para este tipo de determinaciones, de tal forma que puedan obtenerse resultados más rápidos, simples, sensibles y específicos aplicables en todo tipo de laboratorio.

Management of medullary carcinoma of the thyroid: a review.

Medullary thyroid carcinoma (MTC) is an uncommon malignancy of neuroendocrine origin derived from the parafollicular C cells. Although infrequent, the interest in this cancer exceeds its incidence owing to its distinctive features and its characteristic association with other endocrine tumors. Although the majority of MTCs are sporadic, hereditary varieties occur in isolation or as a part of multiple endocrine neoplasia type 2 syndrome (MEN 2). Currently, complete surgical resection of the tumor and nodal metastases with a curative intent remains the mainstay of therapy. The role of adjuvant therapy is limited, although radiotherapy and newer targeted therapies are routinely used for metastatic disease. The lack of consensus in the available guidance regarding the most appropriate diagnostic, therapeutic and follow-up strategies has caused substantial variability in clinical practice. Therefore, this review summarizes the latest available evidence and guidelines on the management of MTC with an emphasis on diagnosis, surgical treatment and follow-up.

Surgical aspects and controversies in the management of medullary thyroid cancer.

Medullary thyroid cancer (MTC) accounts for only 4% of thyroid carcinomas but 15% of thyroid cancer deaths. MTC is a tumour of the calcitonin secreting parafollicular C cells in the thyroid which can occur sporadically or be hereditary in multiple endocrine neoplasias type 2 syndromes due to germline RET mutations. Sporadic forms of MTC can also be caused by mutations in the RET protooncogene. MTC commonly presents in a late stage, with 70% of patients presenting with local nodal metastasis. Currently, the only curative treatment for MTC is surgical removal. The aim of this paper is to describe the current guidelines and progressions of the surgical management of MTC and to highlight up-and-coming chemotherapies. A database literature review was completed utilizing PubMed to cumulate the extant literature, screening for most recent guidelines and publications regarding the management of MTC. Current guidelines were described by the American Thyroid Association in 2015. Controversial publications continue to present supporting evidence for varying degrees of thyroidectomy and neck dissections. Recently, researchers have been exploring non-surgical options including external beam radiotherapy and multikinase inhibitors such as vandetanib and cabozantinib for the treatment of MTC. Surgical management of MTC remains controversial and varies significantly dependent on the extent of disease. Chemotherapeutic options have undetermined effects on survival to date.

Molecular targets of tyrosine kinase inhibitors in thyroid cancer.

Thyroid cancer (TC) is the eighth most frequently diagnosed cancer worldwide with a rising incidence in the past 20 years. Surgery is the primary strategy of therapy for patients with medullary TC (MTC) and differentiated TC (DTC). In DTC patients, radioactive iodine (RAI) is administered after thyroidectomy. Neck ultrasound, basal and thyroid-stimulating hormone-stimulated thyroglobulin are generally performed every three to six months for the first year, with subsequent intervals depending on initial risk assessment, for the detection of possible persistent/recurrent disease during the follow up. Distant metastases are present at the diagnosis in ∼5 % of DTC patients; up to 15 % of patients have recurrences during the follow up, with a survival reduction (70 %-50 %) at 10-year. During tumor progression, the iodide uptake capability of DTC cancer cells can be lost, making them refractory to RAI, with a negative impact on the prognosis. Significant advances have been done recently in our understanding of the molecular pathways implicated in the progression of TCs. Several drugs have been developed, which inhibit signaling kinases or oncogenic kinases (BRAFV600E, RET/PTC), such as those associated with Platelet-Derived Growth Factor Receptor and Vascular Endothelial Growth Factor Receptor. Tyrosine kinase receptors are involved in cancer cell proliferation, angiogenesis, and lymphangiogenesis. Several tyrosine kinase inhibitors (TKIs) are emerging as new treatments for DTC, MTC and anaplastic TC (ATC), and can induce a clinical response and stabilize the disease. Lenvatinib and sorafenib reached the approval for RAI-refractory DTC, whereas cabozantinib and vandetanib for MTC. These TKIs extend median progression-free survival, but do not increase the overall survival. Severe side effects and drug resistance can develop in TC patients treated with TKIs. Additional studies are needed to identify a potential effective targeted therapy for aggressive TCs, according to their molecular characterization.

Multiple endocrine neoplasia type 2: A review.

Multiple endocrine neoplasias are rare hereditary syndromes some of them with malignant potential. Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant hereditary cancer syndrome due to germline variants in the REarranged during Transfection (RET) proto-oncogene. There are two distinct clinical entities: MEN 2A and MEN 2B. MEN 2A is associated with medullary thyroid carcinoma (MTC), phaeochromocytoma, primary hyperparathyroidism, cutaneous lichen amyloidosis and Hirschprung's disease and MEN 2B with MTC, phaeochromocytoma, ganglioneuromatosis of the aerodigestive tract, musculoskeletal and ophthalmologic abnormalities. Germline RET variants causing MEN 2 result in gain-of-function; since the discovery of the genetic variants a thorough search for genotype-phenotype associations began in order to understand the high variability both between families and within family members. These studies have successfully led to improved risk classification of prognosis in relation to the genotype, thus improving the management of the patients by thorough genetic counseling. The present review summarizes the recent developments in the knowledge of these hereditary syndromes as well as the impact on clinical management, including genetic counseling, of both individual patients and families. It furthermore points to future directions of research for better clarification of timing of treatments of the various manifestations of the syndromes in order to improve survival and morbidity in these patients.

How does nintedanib overcome cancer drug-resistant mutation of RET protein-tyrosine kinase: insights from molecular dynamics simulations.

Targeted drug therapies represent a therapeutic breakthrough in the treatment of human cancer. However, the emergence of acquired resistance inevitably compromises therapeutic drugs. Rearranged during transfection (RET) proto-oncogene, which encodes a receptor tyrosine kinase, is a target for several kinds of human cancer such as thyroid, breast, and colorectal carcinoma. A single mutation L881V at the RET kinase domain was found in familial medullary thyroid carcinoma. Nintedanib can effectively inhibit the RET L881V mutant, whereas its analog compound 1 is unable to combat this mutant. However, the underlying mechanism was still unexplored. Here, molecular dynamics (MD) simulations, binding free energy calculations, and structural analysis were performed to uncover the mechanism of overcoming the resistance of RET L881V mutant to nintedanib. Energetic analysis revealed that the L881V mutant remained sensitive to the treatment of nintedanib, whereas it was insensitive to the compound 1. Structural analysis further showed that the distribution of K758, D892, and N879 network had a detrimental effect on the binding of compound 1 to the L881V mutant. The obtained results may provide insight into the mechanism of overcoming resistance in the RET kinase.

Multiple endocrine neoplasia 2A with RET mutation p.Cys611Tyr: A case report.

RATIONALE: Multiple endocrine neoplasia 2A (MEN2A) is a rare autosomal-dominant genetic syndrome, frequently misdiagnosed or neglected clinically, resulting in delayed therapy to patients. PATIENT CONCERNS: A 47-year-old Chinese male patient underwent laparoscopic right adrenal tumorectomy, and postoperative pathology confirmed the tumor as pheochromocytoma (PHEO). He was readmitted to the department of endocrinology and metabolism due to constant increase in carcinoembryonic antigen (CEA) at 5 months after the operation. DIAGNOSIS: The patient was confirmed with medullary thyroid carcinoma (MTC), multiple neck lymph node metastasis, and pituitary microadenoma. The p.Cys611Tyr (c.1832G>A, C611Y) mutation was detected. Therefore, he was diagnosed with MEN2A. INTERVENTIONS: He underwent total thyroidectomy. The gene-sequencing analysis of his family was conducted, and the C611Y mutation was detected in his daughter. OUTCOMES: The level of carcinoembryonic antigen decreased significantly after thyroidectomy in this patient. Long-term follow-up management was conducted. Elevated serum calcitonin and bilateral thyroid nodules were found in his 13-year-old daughter. Thus, MEN2A was highly suspected and she was suggested to undergo total thyroidectomy. CONCLUSION: Patients with MEN2A should be screened regularly and managed by a multidisciplinary team.

Functional impact of a germline RET mutation in alveolar rhabdomyosarcoma.

Specific mutations in the RET proto-oncogene are associated with multiple endocrine neoplasia type 2A, a hereditary syndrome characterized by tumorigenesis in multiple glandular elements. In rare instances, MEN2A-associated germline RET mutations have also occurred with non-MEN2A associated cancers. One such germline mutant RET mutation occurred concomitantly in a young adult diagnosed with alveolar rhabdomyosarcoma, a pediatric and young adult soft-tissue cancer with a generally poor prognosis. Although tumor tissue samples were initially unable to provide a viable cell culture for study, tumor tissues were sequenced for molecular characteristics. Through a hierarchical clustering approach, the index case sample was matched to several genetically similar cell models, which were transformed to express the same mutant RET as the index case and used to explore potential therapeutic options for mutant RET-bearing alveolar rhabdomyosarcoma. We also determined whether the RET mutation associated with the index case caused synthetic lethality to select clinical agents. From our investigation, we did not identify synthetic lethality associated with the expression of that patient's RET variant, and overall we did not find experimental evidence for the role of RET in rhabdomyosarcoma progression.

Case report of adrenocortical carcinoma associated with double germline mutations in MSH2 and RET.

Adrenocortical carcinoma (ACC) is a rare aggressive malignancy that originates in the outer layer of the adrenal gland. Most ACCs are sporadic, but a small percentage of cases are due to hereditary cancer syndromes such as Li-Fraumeni syndrome (LFS), Lynch syndrome (LS), and familial adenomatous polyposis (FAP). Multiple endocrine neoplasia type 2A (MEN2A) is an inherited disorder that predisposes to medullary thyroid cancer, pheochromocytoma, and parathyroid hyperplasia. We present here a case of ACC with both LS and MEN2A; the family and medical history were consistent with Lynch. This is, to our knowledge, the first report of a patient with ACC associated with germline mutations in RET and MSH2, and no phenotypical characteristics of MEN2A.

Homozygosity for the pathogenic RET hotspot variant p.Cys634Trp: A consanguineous family with MEN2A.

Multiple endocrine neoplasia type 2 (MEN2) is a dominantly inherited condition with defined correlations between the genetic variant and clinical presentations. The location of pathogenic variants in the RET gene is a significant determinant of disease presentation and is associated with variable gene activation. Heterozygous pathogenic variants in codon 634 result in earlier onset of medullary thyroid carcinoma and higher incidence of phaeochromocytoma. Here we describe a consanguineous family with MEN2A that includes two children homozygous for the established pathogenic variant p. Cys634Trp. Both parents and a sibling were confirmed to being heterozygotes. Previous reports of biallelic or multiple RET variants have been limited to weakly activating variants. We present the first report of individuals homozygous for the highly activating RET p. Cys634Trp pathogenic variant and discuss disease severity and onset in this rare occurrence.

Genomics and Epigenomics of Medullary Thyroid Carcinoma: From Sporadic Disease to Familial Manifestations.

Our understanding of the genomics and epigenomics of medullary thyroid carcinoma (MTC) has advanced since the initial recognition of RET as a driver of MTC tumorigenesis in familial MTC. We now have insight into the frequency and prognostic significance of specific RET mutations in sporadic MTC. For example, the most common RET mutation in sporadic MTC is the RET Met918Thr mutation, the same mutation that underlies MEN2B and a poor prognosticator. This mutation is relatively infrequent in medullary thyroid microcarcinomas but is over-represented in advanced-stage disease. RAS mutations are detected in 70% of sporadic, RET wild-type MTC. Although next-generation and whole-exome sequencing studies have shown that tumors that are wild-type for RET and RAS mutations essentially lack other recurrent mutations, additional pathways and epigenetic alterations have been implicated in MTC tumorigenesis. Increased insight into the clinical course of patients with familial MTC with specific RET mutations has guided treatment recommendations for these patients. Finally, an understanding of the genomics has informed treatment for patients with advanced MTC. In this review, we will examine the genomics and epigenomics of sporadic and familial MTC, along with the prognostic significance of molecular alterations, management of patients with germline RET mutations, and treatment strategies for MTC patients.

Inherited Follicular Epithelial-Derived Thyroid Carcinomas: From Molecular Biology to Histological Correlates.

Cancer derived from thyroid follicular epithelial cells is common; it represents the most common endocrine malignancy. The molecular features of sporadic tumors have been clarified in the past decade. However the incidence of familial disease has not been emphasized and is often overlooked in routine practice. A careful clinical documentation of family history or familial syndromes that can be associated with thyroid disease can help identify germline susceptibility-driven thyroid neoplasia. In this review, we summarize a large body of information about both syndromic and non-syndromic familial thyroid carcinomas. A significant number of patients with inherited non-medullary thyroid carcinomas manifest disease that appears to be sporadic disease even in some syndromic cases. The cytomorphology of the tumor(s), molecular immunohistochemistry, the findings in the non-tumorous thyroid parenchyma and other associated lesions may provide insight into the underlying syndromic disorder. However, the increasing evidence of familial predisposition to non-syndromic thyroid cancers is raising questions about the importance of genetics and epigenetics. What appears to be "sporadic" is becoming less often truly so and more often an opportunity to identify and understand novel genetic variants that underlie tumorigenesis. Pathologists must be aware of the unusual morphologic features that should prompt germline screening. Therefore, recognition of harbingers of specific germline susceptibility syndromes can assist in providing information to facilitate early detection to prevent aggressive disease.