No correlation between RET immunostaining and the codon 918 mutation in sporadic medullary thyroid carcinoma

Introduction: Medullary thyroid carcinoma (MTC) occurs sporadically or as part of the inherited cancer syndrome, multiple endocrine neoplasia (MEN) type 2. The MEN2 gene has been identified as the RET proto-oncogene. Mutations in the RET proto-oncogene are associated with the pathogenesis of MTC. Approximately 23–40% of sporadic MTCs (sMTCs) have a somatic RET codon 918 mutation within the catalytic core of the tyrosine kinase, which is a mutation found in over 98% of all MEN 2B cases as a germline mutation. Methods: In order to elucidate the role of this mutation, we examined 40 sMTCs for the codon 918 mutation. Simultaneously, we looked for overexpression of the RET protein by means of immunohistochemistry with a newly developed RET antibody. Results: In 8 of 40 tumors (20%), we were able to find a RET codon 918 mutation. Nine of 40 tumors (22.5%) showed immunoreactivity with the RET antibody. Conclusion: The presence of the somatic RET codon 918 mutations did not correlate with the presence of positive RET immunostaining. Received: 29 January 1998 Accepted: 18 July 1998     

遗传性甲状腺髓样癌的基因学基础及诊断治疗

甲状腺髓样癌是一种起源于甲状腺滤泡旁细胞或C细胞的恶性肿瘤,与起源于甲状腺滤泡细胞的其他甲状腺恶性肿瘤有显著的区别.据美国国家癌症数据库(national cancer data base,NCBD)[1]的统计甲状腺髓样癌占甲状腺恶性肿瘤的4%,其中遗传性甲状腺髓样癌占甲状腺髓样癌的75%[2],因此甲状腺髓样癌中大多数为遗传性.遗传性甲状腺髓样癌常有多发性内分泌腺瘤病2型(multiple endocrine neoplasia type 2,MEN2)的主要临床表现,也是造成NEN2患者死亡的主要原因.     

Leflunomide suppresses growth in human medullary thyroid cancer cells

Background

Medullary thyroid cancer (MTC) is a neuroendocrine tumor that arises from the calcitonin-secreting parafollicular cells of the thyroid gland. Leflunomide (LFN) is a disease-modifying antirheumatic drug approved for the treatment of rheumatoid arthritis, and its active metabolite teriflunomide has been identified as a potential anticancer drug. In this study we investigated the ability of LFN to similarly act as an anticancer drug by examining the effects of LFN treatment on MTC cells.

Methods

Human MTC-TT cells were treated with LFN (25–150 μmol/L) and Western blotting was performed to measure levels of neuroendocrine markers. MTT assays were used to assess the effect of LFN treatment on cellular proliferation.

Results

LFN treatment downregulated neuroendocrine markers ASCL1 and chromogranin A. Importantly, LFN significantly inhibited the growth of MTC cells in a dose-dependent manner.

Conclusions

Treatment with LFN decreased neuroendocrine tumor marker expression and reduced the cell proliferation in MTC cells. As the safety of LFN in human beings is well established, a clinical trial using this drug to treat patients with advanced MTC may be warranted.     

Increased incidence of medullary thyroid carcinoma in patients treated for Hirschsprung's disease

Background/Purpose

Mutations of the RET proto-oncogene are responsible for the development of inherited multiple endocrine neoplasia type 2 and familial medullary thyroid carcinoma (MTC). RET mutations are encountered in patients with Hirschsprung's disease (HD). We hypothesized that the incidence of MTC is increased in patients with HD.

Methods

Patients treated for HD at the Children's Hospital, University of Helsinki, during 1939 and 1986 were surveyed for cancer using the population-based countrywide Finnish Cancer Registry from 1967 to 2000. The number of observed cancer cases and that of person-years at risk were counted. The expected number of cancer cases was extrapolated from national cancer incidence rates. To calculate the standardized incidence ratios (SIRs), the observed number of cancer cases was divided by the expected number of cancer cases.

Results

One hundred fifty-six patients (132 males) with HD were identified. The mean length of patient follow-up was 30.9 years. Seven cases of cancer were observed (SIR, 3.5; 95% CI, 1.4-7.3). Two patients developed MTC (SIR, 550; 95% CI, 67-2000). The cases of MTC occurred in male patients at the ages of 34 and 37 years. No patient developed pheochromocytoma.

Conclusions

In this study, we report for the first time an increased risk of MTC occurring in patients treated for HD. The increased risk may be attributed to mutations of the RET proto-oncogene shared by MTC and HD. These findings warrant further studies concerning screening for MTC-type RET mutations in patients with HD.     

Cyclooxygenase-2 expression in medullary thyroid carcinoma

BACKGROUND: Recent studies have demonstrated that cyclooxygenase-2 (COX-2) expression is associated with the carcinogenesis of numerous neoplasms. The aim of this study was to evaluate the role of COX-2 in medullary thyroid carcinoma (MTC). METHODS: Tissue specimens of thyroid neoplasms were obtained from 22 patients with MTC and 15 control subjects with nonmalignant thyroid specimens. RESULTS: This immunohistochemical study confirms the presence of COX-2 in a significant number of MTCs. A large area of staining was noted in only 2 patients in the control group (13%) compared with 18 (82%) in the medullary carcinoma group. On a scale of 0 to 3, the average area of positive staining measured 2.35 in the study group and 0.9 in the control group (p < .0001). The average intensity of staining on a scale of 0 to 5 (deep brown) was 2.15 and 0.8 mm, respectively (p < .001). CONCLUSION: COX-2 is expressed significantly in MTC including a larger area of staining and greater intensity than in nonmalignant thyroid tissue. These findings may have important treatment implications for the use of COX-2 inhibitors in patients with MTC.     

Prophylactic thyroidectomy in pediatric carriers of multiple endocrine neoplasia type 2A or familial medullary thyroid carcinoma: mutation in C620 is associated with Hirschsprung's disease

Purpose

Prophylactic total thyroidectomy is now recommended after having confirmed RET mutations in children of parents with multiple endocrine neoplasia type 2 or familial medullary thyroid carcinoma. We reviewed our experience to determine the incidence of medullary thyroid carcinoma with respect to age at surgery, the location of the mutation, and its association with Hirschsprung's disease (HD).

Methods

A retrospective review from 1996 to 2005 revealed 20 children with genetic screening for multiple endocrine neoplasia type 2A or familial medullary thyroid carcinoma who underwent a prophylactic total thyroidectomy with parathyroid gland preservation.

Results

The median age of the 20 patients (9 boys and 11 girls) included in this study was 8.2 years (range, 3.7-16.9 years) at the time of their surgery. Final pathology revealed normal thyroid tissue (n = 3; median age, 5.9 years), C-cell hyperplasia (n = 13; median age, 10 years), or medullary thyroid carcinoma (n = 4; median age, 8 years). Four children, all with mutations in C620, had a previous diagnosis of HD. At a median follow-up of 3.7 years (range, 1 month to 8.4 years), all patients were well and cancer free.

Conclusions

There is no correlation between histologic findings and median age at surgery. Hirschsprung's disease was found in 50% of the patients with the RET mutation in C620. In children of C620 parents, symptoms of HD should be actively sought, and if such are found, rectal biopsies should be performed even if mutation results are not yet available. Based on the age of the earliest cancer and the safety of total thyroidectomy, children should promptly undergo surgery after genetic screening and before their fifth year of life.     

The importance of early diagnosis in patients with hereditary medullary thyroid carcinoma.

Ninety-two patients from 12 kindreds with hereditary medullary thyroid carcinoma (MTC) were evaluated. We sought to determine if the stimulated plasma calcitonin (CT) level at the time of diagnosis was of prognostic significance. The patients were divided into four groups according to their preoperative stimulated plasma CT levels (1) 250-1,000 pg/ml (n=25); (2) 1,000-5,000 pg/ml (n=36); (3) 5,000-10,000 pg/ml (n=8); (4) greater than 10,000 pg/ml (n=23). Compared between the four groups were several parameters, including incidence of regional lymph node metastases, incidence of residual MTC post-thyroidectomy (as indicated by increased (greater than 300 pg/ml) plasma CT levels after operation), incidence of distant metastases, and incidence of death. Also compared were the incidences of microscopic or gross MTC in thyroidectomy specimens. The incidence of regional lymph node involvement ranged from a minimum of one (4%) of 25 patients in Group 1 to 13 (57%) of 23 patients in Group 4. Similarly, plasma CT levels were elevated in only one (4%) of 25 patients in Group 1 compared to 14 (61%) of 23 patients in Group 4. There was no evidence of distant metastases or death in the patients in Groups 1, 2, or 3. In the 23 patients in group 4, however, four (17.4%) had distant metastases and two (8.7%) died of disease during the period of observation. Of th 25 patients in Group 1, MTC was evident only by microscopic examination in 14 (56%). Eleven (44%) of the patients in Group 1 had macroscopically evident medullary thyroid carcinoma. This is in contrast with patients in Group 4 where all 23 had grossly evident MTC. These data indicate that the stimulated plasma CT level at the time of diagnosis is an excellent prognostic indicator of the extent of a disease in patients with hereditary MTC. Aggressive screening of kindred members at risk is of critical importance for establishing the diagnosis and instituting therapy at a time when the neoplasm is confined to the thyroid gland.     

Failure to Recognize Multiple Endocrine Neoplasia 2B: More Common Than We Think?

Background Multiple endocrine neoplasia 2B (MEN2B) has a classic childhood phenotypic presentation characterized by mucosal neuromas and marfanoid habitus. However, the diagnosis of MEN2B is often delayed beyond childhood, at which time medullary thyroid carcinoma (MTC) may be regionally advanced or metastatic. We examined the extent of this delay and its impact on the treatment of MTC. Methods Patients in the MEN database were retrospectively analyzed to determine the age at first presentation for a MEN2B-related complaint and the subsequent time to correct diagnosis. Operative and pathology reports were reviewed to determine the extent of thyroidectomy and cervical lymphadenectomy during the initial and subsequent neck operations. Results We identified 22 patients with MEN2B, 20 were de novo cases and a M918T RET gene mutation was confirmed in 18 of the 22 patients. Median age at diagnosis of MTC was 13 years (range 6–25 years). The median delay in diagnosis was 26 months (range 0–18 years). Persistent local-regional MTC was present following the initial cervical operation in 12 of 22 patients (55%); including 4 of 13 with MEN2B diagnosed prior to initial surgery and 8 of 9 with MEN2B diagnosed after initial surgery. Conclusions Most patients displayed phenotypic characteristics of MEN2B long before the correct diagnosis was made. Half of the patients failed to undergo complete resection of MTC at their initial thyroid surgery. Early recognition of the MEN2B phenotype with a thoughtful approach to preoperative staging and surgery will maximize control of MTC and minimize the need for reoperation. Presented at the 60th Annual Meeting of the Society of Surgical Oncology. March 16, 2007, Washington DC     

Hyalinizing trabecular adenoma--an uncommon thyroid tumor frequently misdiagnosed as papillary or medullary thyroid carcinoma

BACKGROUND: Hyalinizing trabecular adenoma (HTA) is an uncommon benign thyroid tumor that can present as a solitary thyroid nodule, a prominent nodule in a multinodular goiter, or as an incidental finding in a thyroidectomy specimen. The clinical significance of the lesion is that it is frequently misdiagnosed as papillary carcinoma on fine-needle aspiration cytology or as papillary or medullary carcinoma on histopathological section. We reviewed our recent experience with 7 patients diagnosed with HTA. METHODS: Fine-needle aspiration biopsy was performed in 7 patients presenting with a solitary thyroid nodule (n = 4) or a multinodular goiter (n = 3). The patients underwent total thyroidectomy (n = 6) or hemithyroidectomy (n = 1). RESULTS: In 4 patients, the preoperative cytology was suggestive of papillary carcinoma, in 2 patients suspicious, and in 1 patient positive for papillary carcinoma. On histopathological section, 2 patients had a microscopic HTA, 2 patients had HTA in 1 or 2 nodules of a multinodular goiter, and 3 patients had HTA in a solitary nodule. Except in 1 patient, who had a microscopic focus (3.2 mm) of papillary carcinoma, there was no evidence of malignancy in the surgical specimens on permanent histopathological section. CONCLUSIONS: Although HTA is a rare condition of the thyroid, the surgeon needs to be aware of this entity to be able to better discuss the pathological findings with the patient, particularly since some pathologists and endocrinologists believe that HTA may represent a malignant neoplasm of low metastatic potential.     

甲状腺髓样癌临床诊疗方案分析

目的:探讨影响甲状腺髓样癌（medullary thyroid carcinoma,MTC）治疗方案制订与转归的关键要素。方法:回顾性分析2007年4月至2020年3月湖南省人民医院乳甲外科收治的23例MTC患者病例资料、典型病例的临床特点及生存随访结果,结合ATA等指南对MTC治疗方案和转归进行分析。结果:23例MT...     

Somatic mutations in the RET protooncogene in Japanese and Chinese sporadic medullary thyroid carcinomas

Objective.Despite advances in the understanding of the genotype-phenotype correlation in multiple endocrine neoplasia type 2A and 2B(MEN 2A,MEN 2B),and familial medullary thyroid carcinoma (FMTC),the frequency and prognostic relevance of RET protoonco-gene mutations in sporadic medullary thyroid carcinomas (MTCs) remain controversial.Methods To study somatic mutations in the RET protooncogene in Japanese and Chinese sporadic MTCs and to comparatively analyze the correlation between RET mutation and tumor differentiation,we in-vestigated somatic mutations in the RET protooncogene in 20 Japanese and 20 Chinese sporadic MTCs by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.Results Of the 40 sporadic MTCs,13 had a point mutation in codon 918 of exon 16,a frequency of 32.5%。There was no significant difference in the frequency between Japanese and Chinese sporadic MTCs,as 30% of the Japanese and 35% of the Chinese sporadic MTCs contained this mutation.We did not observe any correlation between the presence or absence of codon 918 mutation and tumor differentiation in either Japanese or Chinese sporadic MTCs.Conclusion Our findings indicate that the frequency of RET somatic mutations is similar in Japanese and Chi-nese sporadic MTCs,and the presence or absence of RET mutation does not correlate with the differentiation of sporadic MTCs.     

Focal adhesions and associated proteins in medullary thyroid carcinoma cells

BACKGROUND: In medullary thyroid carcinoma (MTC), mutations in the RET protooncogene lead to oncogenic transformation. RET activation in other cell types has been shown to cause phosphorylation of the focal adhesion-associated proteins focal adhesion kinase (FAK), paxillin, and p130(CAS). We hypothesized that adhesion-dependent signaling might be deranged in MTC cells. METHODS: Indirect immunofluorescence was used to label beta(1) integrin, FAK, paxillin, and p130CAS. Rhodamine-labeled phalloidin was used to visualize actin microfilaments. Phosphorylated protein was detected by immunoprecipitation followed by Western blotting for phosphotyrosine. MTC cell invasiveness was quantified using a modified Boyden chamber assay. RESULTS: Clustering of beta(1) integrin, FAK, paxillin, and p130(CAS) into focal adhesions were not detected in MTC cells under any conditions, although clustering was seen as expected in control HeLa cells. Despite this failure, FAK, paxillin and p130(CAS) were all found to be phosphorylated. Actin microfilaments were generally not seen although in a few cells, small, poorly formed microfilaments could be detected. MTC cells invaded poorly as compared with highly invasive cell lines. However a clear difference was noted between invasiveness on growth factor depleted Matrigel and regular Matrigel. CONCLUSIONS: In MTC cells, focal adhesions are not seen in response to interaction with extracellular matrix. Consistent with this failure, actin microfilaments are absent or poorly formed and invasion is weak. Despite the absence of focal adhesions, focal adhesion proteins remain phosphorylated, even though in normal cells their signaling activity is dependent on focal adhesion formation. Deranged adhesion-dependent signaling may contribute to MTC pathogenesis.     

German medullary thyroid carcinoma/multiple endocrine neoplasia registry

Introduction: A national registry for medullary thyroid carcinoma (MTC) and multiple endocrine neoplasia type 2 (MEN2) was set up to evaluate epidemiological, clinical and prognostic factors of the sporadic and hereditary forms of MTC. Patients and methods: Coded data from 1217 patients with MTC from 57 participating centers in Germany were registered and statistically analyzed. The series included 515 (42%) males (mean age 43.1±16.1 years) and 702 (58%) females (mean age 44.4±17.6 years), with a mean follow-up of 5.2 years; 865 (71%) exhibited the sporadic form and 352 (29%) the familial form (244 MEN2a, 32 MEN2b, 76 FMTC). The mean age at diagnosis was 49 years for sporadic and 30 years for the familial form. Results: Of the patients, 17% presented at stage I, according to the UICC, and 30%, 45%, and 8% presented at stages II, III, and IV, respectively. There were 12% of patients who died of the disease. The overall adjusted survival rate was 87% at 5 years, and 76% at 10 years. In a univariate analysis, the stage of disease at diagnosis, age, gender, and form were relevant prognostic factors. In a multivariate proportional-hazards analysis, the difference between patients with sporadic and familial disease disappeared. Conclusion: As the tumor stage at presentation is the major prognostic factor, early diagnosis and surgical intervention before cervical lymph node metastases appear is necessary to improve survival especially in sporadic cases. Received: 28 January 1998 / Accepted: 3 July 1998     

Role of RET codonic mutations in the surgical management of medullary thyroid carcinoma in pediatric age multiple endocrine neoplasm type 2 syndromes

Purpose

Hereditary medullary thyroid carcinoma (MTC) therapy is surgical resection. Because the genetic screening was available, the early diagnosis of the disease has been possible. The purpose of this study was to evaluate the role of the genetic test in the management of these children and to draw some information about the surgical timing.

Methods

Thirteen patients underwent total thyroidectomy at our institute between 1995 and 2007. Seven patients underwent a curative thyroidectomy, and 6 patients underwent a prophylactic thyroidectomy. Two patients were operated with a minimally invasive video-assisted technique. We studied the following parameters: age, risk level associated to the RET gene mutations, aim of surgery (curative or prophylactic), tumor histopathologic features, lymph node involvement, and distal metastases.

Results

We found a statistical association between cancer maximum diameter and some parameters analyzed: age of patients, aim of surgery, single or multifocal MTC, and number of organs involved by distal metastases. Cancer diameter at the moment of diagnosis seems to increase according to the aggressiveness of RET gene mutation found.

Conclusions

The best strategy to cure MTC is to prevent it. Genetic screening could be a fundamental tool in the management of multiple endocrine neoplasm type 2 children. An improvement of scientific knowledge regarding RET gene alterations and an early and appropriate use of genetic tests could allow a better understanding of the correct surgical timing and a wider use of less aggressive surgical procedures.     

Renal genetics in Australia: Kidney medicine in the genomic age

There have been few new therapies for patients with chronic kidney disease in the last decade. However, the management of patients affected by genetic kidney disease is rapidly evolving. Inherited or genetic kidney disease affects around 10% of adults with end‐stage kidney disease and up to 70% of children with early onset kidney disease. Advances in next‐generation sequencing have enabled rapid and cost‐effective sequencing of large amounts of DNA. Next‐generation sequencing‐based diagnostic tests now enable identification of a monogenic cause in around 20% of patients with early‐onset chronic kidney disease. A definitive diagnosis through genomic testing may negate the need for prolonged diagnostic investigations and surveillance, facilitate reproductive planning and provide accurate counselling for at‐risk relatives. Genomics has allowed the better understanding of disease pathogenesis, providing prognostic information and facilitating development of targeted treatments for patients with inherited or genetic kidney disease. Although genomic testing is becoming more readily available, there are many challenges to implementation in clinical practice. Multidisciplinary renal genetics clinics serve as a model of how some of these challenges may be overcome. Such clinics are already well established in most parts of Australia, with more to follow in future. With the rapid pace of new technology and gene discovery, collaboration between expert clinicians, laboratory and research scientists is of increasing importance to maximize benefits to patients and health‐care systems.     

Presymptomatic screening for medullary thyroid carcinoma in patients with multiple endocrine neoplasia type 2A

Presymptomatic screening of medullary thyroid carcinoma in MEN IIA families enables the early diagnosis of this tumor with its significant morbidity. Biochemical screening consists of basal and stimulated serum calcitonin evaluation. Genetic screening is based on DNA analysis using linked DNA markers. Thyroidectomy at an occult tumor stage may be curative. Calcitonin measurement was carried out in 58 apparently unaffected family members at risk and 11 MEN IIA patients. Calcitonin elevation was detected in nine individuals. All nine underwent thyroidectomy. Histologic examination confirmed medullary thyroid carcinoma in eight patients and in one case C cell hyperplasia. Postoperatively, eight patients (89%) are clinically and biochemically tumor-free (mean follow-up 30 months). DNA screening results in one affected family are presented. DNA analysis allowed recognition of one apparently unaffected individual at risk as a MEN IIA gene carrier. One family member at risk was found not to carry the gene and may be excluded from further screening.

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Resumen El tamizaje presintomático del carcinoma medular de la glándula tiroides en familias con síndrome NEM 2A hace posible el diagnóstico precoz de este tumor, el cual en forma característica se asocia con significativa morbilidad. El tamizaje bioquímico consiste en la determinación de los niveles calcitonina sérica basal y estimulada. El tamizaje genético se basa en el análisis de ADN utilizando marcadores ligados al ADN. La tiroidectomía que se realiza cuando el tumor es todavía clínicamente oculto puede ser curativa. La determinación de calcitonina fue realizada en 58 familiares aparentemente no afectados pero de reconocido riesgo y en 11 pacientes con síndrome NEN 2A; se detectó calcitonina elevada en 9 individuos, y todos los nueve fueron sometidos a tiroidectomía. El examen histológico confirmó carcinoma medular en 8 e hiperplasia de células C en 1. Postoperatoriamente 8 pacientes (89%) se hallan clínica y bioquimicamente libres de tumor (promedio del seguimiento, 30 meses). Se presentan los resultados del tamizaje de ADN en una familia afectada. El análisis de ADN permitió el reconocimiento de un individuo aparentemente no afectado pero de riesgo como portador del gen NEM 2A. Un familiar con riesgo fue marcado como no portador del gen y puede ser excluído de tamizajes ulteriores.

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Résumé Le dépistage du cancer médullaire de la thyroïde avant l'apparition des symptômes dans les familles MEN 2A facilite le diagnostic de cette maladie accompagnée d'une morbidité non négligeable. Le dépistage biochimique consiste en une évaluation de la calcitonine basale et stimulée. Le dépistage génétique comporte une analyse de l'ADN qui utilise des marqueurs spécifiques des liaisons d'ADN. La thyroïdectomie a des chances d'être curative au stade de tumeur occulte. La calcitonine a pu ètre mesurée chez 58 membres d'une famille atteinte mais sans symptômes et chez 11 patients MEN 2A. La calcitonine était élevée chez 9. Tous ces patients ont eu une thyroïdectomie et un cancer médullaire a été retrouvé chez 8 et une hyperplasie des cellules C chez le neuvième. Postopérativement, 8 patients (89%) sont sans tumeur clinique et biologique (suivi moyen: 30 mois). Les résultats du dépistage par l'ADN chez une famille atteinte sont présentés et a permis d'identifier un seul membre apparemment non symptomatique qui était à risque de porter le gêne MEN 2A. On a déterminé également qu'un membre n'était pas porteur du gêne; il peut être exclu de tout examen de dépistage ultérieur.

     

血管内皮细胞生长因子受体在甲状腺髓样癌中的高表达

目的:评估血管内皮细胞生长因子受体1(VEGFR-1)和VEGFR-2在甲状腺髓样癌(medullary thyroidcarcinoma,MTC)组织的表达,探讨其与MTC病人临床数据间的关系。方法:用免疫组化技术评估24例MTC病人的石蜡包埋组织VEGFR-1和VEGFR-2的表达,回顾收集病人的临床数据。结果:24例病人平均年龄(44.9±14.1)岁,8例(33.3%)为遗传性,其中6例为多发性内分泌肿瘤(multiple endocrine neoplasia,MEN)-2A,2例为MEN-2B。VEG-FR-1免疫组化染色阳性率为91.7%(22/24),VEGFR-2为87.5%(21/24)。年龄与VEGFR-2染色强度为正相关(r=0.609,P=0.002)。VEGFR-2与肿瘤分期(肿瘤淋巴结转移)、肿瘤大小、病人血清CEA及降钙素在手术前后的相对降幅间没有关联。然而,VEGFR-1与肿瘤分期呈负相关(r=-0.660,P=0.0005),而与MTC病人血清CEA及降钙素在手术前后的相对降幅之间均呈正相关(CEA:r=0.869,降钙素:r=0.849,P0.05)。结论:VEGFR-1和VEGFR-2在MTC病人中高表达,且可能参与肿瘤的进展。