Hereditary Medullary Thyroid Carcinoma Research Articles

Incidence and prevalence of multiple endocrine neoplasia 2A in Denmark 1901-2014: a nationwide study.

BackgroundThe incidence and prevalence of multiple endocrine neoplasia 2A (MEN2A) have only been reported once in a nationwide setting. However, it is unclear whether the figures are representative of other populations, as the major component of the syndrome, hereditary medullary thyroid carcinoma (MTC), has been reported as rare in the same country. We conducted a nationwide retrospective cohort study of MEN2A in Denmark from 1901 to 2014, aiming to describe the incidence and prevalence.MethodsThis study included 250 unique MEN2A patients born or resident in Denmark before December 31, 2014. Patients were identified through the Danish REarranged during Transfection (RET) cohort, linkage of MEN2A pedigrees, the Danish MTC cohort, a nationwide collaboration of MEN2 centers, cross-checking of other relevant cohorts, and a systematic literature search.ResultsThe incidence from 1971 to 2000 was 28 (95% CI: 21–37) per million live births per year. Incidence for the specific mutations or for the overall MEN2A group did not change significantly from 1901 to 2014 (P>0.05). Point prevalence at January 1, 2015, was 24 per million (95% CI: 20–28).ConclusionThe incidence and prevalence of MEN2A in Denmark seem higher than those reported in other countries. This is likely explained by the Danish C611Y founder effect. Also, our data indicate no significant change in MEN2A incidence during the last century.

Static Prognostic Factors and Appropriate Surgical Designs for Patients with Medullary Thyroid Carcinoma: The Second Report from a Single-Institution Study in Japan

BackgroundMedullary thyroid carcinoma (MTC) originates from calcitonin-producing cells of the thyroid. In 2009, we published our first report on the biological characteristics and prognosis of 118 MTC patients. Herein, we enrolled a larger number of patients with longer follow-up periods to further study the biological characteristics and appropriate therapies for MTC.MethodsIn general, hemithyroidectomy and total thyroidectomy were performed for sporadic MTC confined to the thyroid lobe and for hereditary MTC with central node dissection, respectively. Moreover, prophylactic modified radical neck dissection was performed on the side of macroscopic tumors.ResultsIn total, 233 patients (99 hereditary and 134 sporadic) were enrolled. The median follow-up time was 128 months (range 7–445 months). Biochemical cure was obtained in 36 (62%) of the 58 patients who underwent prophylactic MND and were pathologically positive for lateral node metastasis. None of the patients had recurrence in the preserved thyroid. Distant recurrence was detected in 19 patients, and 12 died of MTC. Preoperative calcitonin and carcinoembryonic antigen levels, tumor size (T) > 4 cm, the male sex, clinical and pathological node metastases (N1), distant metastasis (M1), extrathyroid extension (Ex), and a lack of biochemical cure had prognostic impacts on distant recurrence and/or carcinoma-related mortality on univariate analysis. On multivariate analysis, Ex was independently correlated with distant recurrence, and Ex, T > 4 cm, and M1 independently affected carcinoma-related mortality.ConclusionMTC patients had excellent prognosis in our institutions, indicating that our surgical strategies were appropriate.

Update on Multiple Endocrine Neoplasia Type 2: Focus on Medullary Thyroid Carcinoma.

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant hereditary cancer syndrome caused by missense gain-of-function mutations in the RET proto-oncogene on chromosome 10. Specific RET mutations can predispose toward a particular phenotype and clinical course, with strong genotype–phenotype correlations. MEN2 is highly penetrant in medullary thyroid carcinoma (MTC), and it can be associated with bilateral pheochromocytoma and primary hyperparathyroidism. Two different clinical variants of MEN2 are known: MEN2A, which includes the familial subtype, and MEN2B. Treatment includes early thyroidectomy. Recommendations on the timing and extent of surgery are based on the RET mutation risk categories (moderate-, high-, or highest-risk) regarding the age of MTC onset. Early identification of patients with hereditary MTC has improved treatment outcomes. Previously, MTC was diagnosed based on clinical tumors; in contrast, with genetic screening, MTC can be diagnosed at preclinical disease states. This approach has resulted in a high cure rate and a much better prognosis for MTC. However, classification into one of the three RET mutation risk groups for predicting aggressiveness and prognosis has had limited impact. Increasing evidence has shown that patients with RET mutations in different risk classifications exhibit a broad spectrum of MTC aggressiveness during follow-up, with no relevant difference in survival. The specific germline activating mutation of the RET proto-oncogene appears to be the first determinant of the age of MTC onset, but, presumably, different regulatory events determine long-term tumor behavior.

Genotypic characteristics and their association with phenotypic characteristics of hereditary medullary thyroid carcinoma in Korea

BackgroundHereditary medullary thyroid carcinoma can present as a part of multiple endocrine neoplasia syndrome by rearranged during transfection gene mutation. We evaluated the prevalence of rearranged during transfection gene mutation in patients who have medullary thyroid carcinoma and the correlations of genotype with medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism according to the revised American Thyroid Association risk level. MethodsA total of 331 patients were diagnosed with medullary thyroid carcinoma, 172 of whom were tested for the rearranged during transfection germline mutation by sequencing of exon 8, 10, 11, and 13–16. These patients were diagnosed during the years 1982–2012 at 2 Korean tertiary hospitals. Patients were analyzed according to the route of diagnosis (screened versus index cases) or the mutational site of rearranged during transfection gene (the American Thyroid Association risk group). ResultsRearranged during transfection mutation was found in 23.8% of patients tested, showing a decreasing trend with time. The most commonly mutated codon was codon 634 (37.1%), followed by codon 918 (14.3%). rearranged during transfection–positive patients were younger than rearranged during transfection–negative patients, although no other clinicopathologic characteristics differed. Screened cases were younger and had smaller tumors than index cases. Among rearranged during transfection–positive patients, pheochromocytoma manifested in 35.1% and hyperparathyroidism in 7.0%. Notably, pheochromocytoma and hyperparathyroidism emerged at any time after the diagnosis of medullary thyroid carcinoma. The American Thyroid Association risk-group analysis demonstrated that medullary thyroid carcinoma patients in the highest risk group were younger, had larger tumors, and higher disease-specific mortality. Similar results for pheochromocytoma were found, according to the American Thyroid Association risk group, although the results were not significant. ConclusionsKorean patients who have medullary thyroid carcinoma showed a similar distribution of rearranged during transfection gene mutation with those in Western countries. The American Thyroid Association risk classification was shown to be useful for pheochromocytoma, as well as for medullary thyroid carcinoma. Familial screening for rearranged during transfection mutation and lifelong monitoring for associated pheochromocytoma should be emphasized in hereditary medullary thyroid carcinoma.

Incidence and prevalence of sporadic and hereditary MTC in Denmark 1960-2014: a nationwide study.

Recent studies have shown a significant increase in the temporal trend of medullary thyroid carcinoma (MTC) incidence. However, it remains unknown to which extent sporadic medullary thyroid carcinoma (SMTC) and hereditary MTC (HMTC) affect the MTC incidence over time. We conducted a nationwide retrospective study using previously described RET and MTC cohorts combined with review of medical records, pedigree comparison and relevant nationwide registries. The study included 474 MTC patients diagnosed in Denmark between 1960 and 2014. In the nationwide period from 1997 to 2014, we recorded a mean age-standardized incidence of all MTC, SMTC and HMTC of 0.19, 0.13 and 0.06 per 100,000 per year, respectively. The average annual percentage change in incidence for all MTC, SMTC and HMTC were 1.0 (P = 0.542), 2.8 (P = 0.125) and −3.1 (P = 0.324), respectively. The corresponding figures for point prevalence at January 1, 2015 were 3.8, 2.5 and 1.3 per 100,000, respectively. The average annual percentage change in prevalence from 1998 to 2015 for all MTC, SMTC and HMTC was 2.8 (P < 0.001), 3.8 (P < 0.001) and 1.5 (P = 0.010), respectively. We found no significant change in the incidence of all MTC, SMTC and HMTC possibly due to our small sample size. However, due to an increasing trend in the incidence of all MTC and opposing trends of SMTC (increasing) and HMTC (decreasing) incidence, it seems plausible that an increase for all MTC seen by others may be driven by the SMTC group rather than the HMTC group.

Outcomes of Children and Adolescents with Advanced Hereditary Medullary Thyroid Carcinoma Treated with Vandetanib.

Purpose: Vandetanib is well-tolerated in patients with advanced medullary thyroid carcinoma (MTC). Long-term outcomes and mechanisms of MTC progression have not been reported previously.Experimental Design: We monitored toxicities and disease status in patients taking vandetanib for hereditary, advanced MTC. Tumor samples were analyzed for molecular mechanisms of disease progression.Results: Seventeen patients [8 male, age 13 (9-17)* years] enrolled; 16 had a RET p.Met918Thr germline mutation. The duration of vandetanib therapy was 6.1 (0.1-9.7+)* years with treatment ongoing in 9 patients. Best response was partial response in 10, stable disease in 6, and progressive disease in one patient. Duration of response was 7.4 (0.6-8.7+)* and 4.9 (0.6-7.8+)* years in patients with PR and SD, respectively. Six patients died 2.0 (0.4-5.7)* years after progression. Median progression-free survival (PFS) was 6.7 years [95% confidence interval (CI): 2.3 years-undefined] and 5-year overall survival (OS) was 88.2% (95% CI: 60.6%-96.9%). Of 16 patients with a RET p.Met918Thr mutation, progression-free survival was 6.7 years (95% CI: 3.1-undefined) and 5-year overall survival was 93.8% (95% CI: 63.2%-99.1%). No patients terminated treatment because of toxicity. DNA sequencing of tissue samples (n = 11) identified an increase in copy number alterations across the genome as a potential mechanism of drug resistance [*median (range)].Conclusions: This study demonstrates that vandetanib is safe and results in sustained responses in children and adolescents with hereditary MTC. Our preliminary molecular data suggest that an increase in copy number abnormalities may be associated with tumor progression in hereditary MTC patients treated with vandetanib. Clin Cancer Res; 24(4); 753-65. ©2017 AACR.

Modifying impact of RET gene haplotypes on medullary thyroid carcinoma clinical course.

The clinical course of medullary thyroid carcinoma (MTC) associated with the MEN2A syndrome as well as of sporadic MTC shows considerable heterogeneity. The disease picture varies not only between the same RET proto-oncogene mutation carriers but also among sporadic MTC patients with no RET germinal mutations, which suggests the involvement of additional modulators of the disease. However, genetic factors responsible for this heterogeneity of the MTC clinical course still remain unknown. The aim of this study was to determine if polymorphic variants or specific haplotypes of the RET gene may modify the MTC clinical course. We genotyped the following loci: c.73+9277T>C, c.135G>A, c.1296A>G, c.2071G>A, c.2307T>C, c.2508C>T and c.2712C>G in 142 MTC patients and controls. We demonstrated considerable differences in the genotypes distribution within c.73+9277T>C, c.135G>A and c.2307T>C loci Our results show that the c.73+9277T variant associated with a decreased activity of the MCS+9.7 RET enhancer is rare in hereditary MTC patients with primary hyperparathyroidism, and thus, may influence the MTC clinical picture. The decreased activity of the RET promoter enhancer reduces RET expression level and may counterbalance the activating mutation in this gene. Frequent co-occurrence of the c.73+9277T allele with p.E768D, p.Y791F, p.V804M or p.R844Q RET mutations may be associated with their attenuation and milder clinical picture of the disease. Haplotypes analysis showed that C-G-A-G-T-(C)-C (c.73+9277T>C - c.135G>A - c.1296A>G - c.2071G>A - c.2307T>G - (c.2508C>T) - c.2712C>G) alleles combination predisposes to pheochromocytomas and primary hyperparathyroidism. We consider that RET haplotypes defining may become an auxiliary diagnostic tool in MTC patients.

A pioneering RET genetic screening study in the State of Ceará, Brazil, evaluating patients with medullary thyroid cancer and at-risk relatives: experience with 247 individuals.

Initial diagnosis of medullary thyroid carcinoma (MTC) is frequently associated with advanced stages and a poor prognosis. Thus, the need for earlier diagnoses and detection in relatives at risk for the disease has led to increased use of RET genetic screening. We performed RET screening in 247 subjects who were referred to the Brazilian Research Consortium for Multiple Endocrine Neoplasia (BRASMEN) Center in the State of Ceará. Direct genetic sequencing was used to analyze exons 8, 10, 11, and 13-16 in MTC index cases and specific exons in at risk relatives. Afterward, clinical follow-up was offered to all the patients with MTC and their affected relatives. RET screening was performed in 60 MTC index patients and 187 at-risk family members. At the initial clinical assessment of the index patients, 54 (90%) were diagnosed with apparently sporadic disease and 6 (10%) diagnosed with hereditary disease. After RET screening, we found that 31 (52%) index patients had sporadic disease, and 29 (48%) had hereditary disease. Regarding at-risk relatives, 73/187 were mutation carriers. Mutations in RET codon 804 and the rare p.M918V mutation were the most prevalent. Performing RET screening in Ceará allowed us to identify a different mutation profile in this region compared with other areas. RET screening also enabled the diagnosis of a significant number of hereditary MTC patients who were initially classified as sporadic disease patients and benefited their relatives, who were unaware of the risks and the consequences of bearing a RET mutation.

Advances in the management of MEN2: from improved surgical and medical treatment to novel kinase inhibitors.

Medullary thyroid carcinoma (MTC), a tumor derived from the neural crest, occurs either sporadically or as the dominant component of the type 2 multiple endocrine neoplasia (MEN) syndromes, MEN2A and MEN2B. The discovery that mutations in the RET protooncogene cause hereditary MTC was of great importance, since it led to the development of novel methods of diagnosis and treatment. For example, the detection of a mutated RET allele in family members at risk for inheriting MEN2A or MEN2B signaled that they would develop MTC, and possibly other components of the syndromes. Furthermore, the detection of a mutated allele created the opportunity, especially in young children, to remove the thyroid before MTC developed, or while it was confined to the gland. The discovery also led to the development of molecular targeted therapeutics (MTTs), mainly tyrosine kinase inhibitors, which were effective in the treatment of patients with locally advanced or metastatic MTC. While responses to MTTs are often dramatic, they are highly variable, and almost always transient, because the tumor cells become resistant to the drugs. Clinical investigators and the pharmaceutical industry are focusing on the development of the next generation of MTTs, which have minimal toxicity and greater specificity for mutated RET.

Long-Term Outcome After Surgery for Medullary Thyroid Carcinoma: A Single-Center Experience.

Medullary thyroid carcinoma (MTC) is a rare C cells-derived tumor, with a hardly predictable long-term prognosis. This study was aimed to evaluate the predictive factors of cure and survival after surgery for MTC in a monocentric series. A retrospective analysis of the long-term outcomes was assessed in 255 MTC patients operated between 1980 and 2015 at Padua University hospital. Sporadic MTC occurred in 65.1% and hereditary MTC in 34.9% of patients. At a median follow-up of 93months (range 7-430), the cure rate was 56.8%. The overall 10-year survival was 84.4%, and MTC-related death rate was 15.3%. Patients who died because of MTC had a median age of 61years (range 21-84) and were at stages III-IV in all cases; deaths occurred in 18% of sporadic MTC, 6% of MEN2a and 66.7% of MEN2b patients. None of the patients at stages I-II died because of the disease, but 17.7% had persistent/recurrent disease. Based on univariate analysis, age, gender, genetic variant, extent and year of surgery, tumor size, lymph-nodal metastases and tumor stage significantly affected cure and survival rates. At multivariate analysis, only patient- and tumor-related features (age, lymph-nodal status and stage) remained significant independent prognostic factors. Radical surgery is the only chance of definitive cure in MTC, but it is possible only at early stage; in advanced stages, even extensive surgery could not grant cure and prolonged survival. Stage, nodal metastases and age remain the main predictive factors for cure and survival.

Outcomes of children with hereditary medullary thyroid carcinoma (MTC) treated with vandetanib.

10540 Background: Vandetanib is well tolerated and active in children with advanced or metastatic hereditary MTC (NCT00514046) [data cutoff 7/2011; Clin Cancer Res. 2013 Aug 1;19(15):4239-48]. We report outcomes as of 1/2017. Methods: We monitored toxicities, RECISTv1.0, carcinoembryonic antigen (CEA), and calcitonin (CT) response. Patients (pts) removed from the vandetanib trial were followed on a natural history study (NCT01660984). Results: Of 17 pts (8 male, age 13 years (9-17)*) enrolled, 1 was lost to follow-up. Of the 16 pts analyzed, 15 had a RET p.M918T germline mutation. The duration of vandetanib therapy was 5.6 years (0.1-9.2+) with treatment ongoing in 8 pts. Best response was partial response (PR) in 10, stable disease (SD) in 5, and progressive disease (PD) in 1 pt. Time to achieve PR (n = 10) was 0.6 years (0.4-2.4). Time to best response (n = 16) was 1.5 years (0.1-4.1). Duration of response was 5.1 years (1.3-8.6+) in pts with PR and 4.8 years (0.6-7.3+) in pts with SD. Seven of 8 pts with PD subsequently received sunitinib, sorafenib, and/or cabozantinib. Disease progression occurred as increase in target (n = 2), non-target/new lesions (n = 5), or CT/CEA (n = 1). Six pts died from disease 2.1 years (0.4-4.3) after stopping vandetanib. Progression free survival was 6.2 years (95% CI 3.0-na) and overall survival was 7.9 years (95% CI 5.9-na).Pts had no difference in enrollment age, baseline CT/CEA, or tumor size per response categories (n = 16). Rate of CEA/CT decrease during initial 4 months of treatment was not associated with PR/SD compared to PD (n = 16). While on vandetanib, 6 pts with PD had CEA or CT doubling time (DT) of &lt; 2 years within 1 year prior to PD. All pts with ongoing PR/SD had CEA and CT DT &gt; 2 years while on vandetanib. No pts came off treatment for toxicity. Dose reductions occurred in 8 pts for grade (gr) 2 weight loss (n = 2), palpitations (n = 1), arrhythmia (n = 1), elevated creatinine (n = 1), diarrhea (n = 2), and gr 3 constipation (n = 1). Conclusions: Many children with hereditary MTC sustained PR/SD on vandetanib. However, half ultimately developed PD and died from disease despite treatment with other targeted therapies. CEA/CT DT &lt; 2 years within 1 year of progression on vandetanib may be associated with PD. *Median (range)

Surgical approaches in hereditary endocrine tumors.

Endocrine tumors of thyroid, adrenal and parathyroid glands may be due to germline and inheritable mutations in 5-30% of patients. Medullary Thyroid Carcinoma, Pheochromocytoma, Paraganglioma, and Familial Primary Hyperparathyroidism are the most frequent entity. Hereditary endocrine tumors usually have a suggestive familial history; they occur earlier than sporadic variants, are multifocal, and have increased recurrence rates. They may be present as isolated variant or associated to other neoplasms in a syndromic setting. Genetic diagnosis should be preferably available before surgery because specific and targeted operative management are needed to achieve the best chance of cure. This review was aimed to discuss the surgical approaches for some of the most frequent hereditary endocrine tumors of thyroid, adrenal and parathyroid glands, focusing on medullary thyroid carcinoma, Pheochromocytoma, Paraganglioma and hereditary primary hyperparathyroidism (pHPT). Hereditary Medullary Thyroid Carcinoma is caused by RET mutations, and may be associated to Pheochromocytomas in MEN 2 setting. Total thyroidectomy and at least central neck nodal dissection is required. The availability of genetic screening allows prophylactic or early surgery in asymptomatic patients, with subsequent definitive cure. Hereditary Pheochromocytomas may be present in several syndromes (MEN 2, VHL, NF1, Paraganglioma/Pheochromocytoma syndrome); it may involve both adrenals; in these cases, a cortical sparing adrenalectomy should be performed to avoid permanent hypocorticosurrenalism. Hereditary Primary Hyperparathyroidism may frequently occur associated to MEN 1, MEN 2A, MEN 4, Hyperparathyroidism-Jaw Tumor Syndrome; it may involve all the parathyroid glands, requiring subtotal parathyroidectomy or total parathyroidectomy plus autotransplantation. In some cases, a selective parathyroidectomy might be performed.

Is new American Thyroid Association risk classification for hereditary medullary thyroid carcinoma applicable to Chinese patients? A single-center study.

ObjectiveThe American Thyroid Association (ATA) proposed a new risk classification for hereditary medullary thyroid carcinoma (MTC) in 2015. This study aimed to assess whether the new guidelines are suitable for the Chinese population, and reported our experience on prophylactic thyroidectomy.MethodsA total of 73 patients from 22 families were screened as rearranged during transfection (RET) mutation carriers from 2010 to 2016 in Cancer Hospital, Chinese Academy of Medical Science; the medical history for each patient was collected. Based on the initial treatment, we identified the risk factors for poor prognosis by univariate and multivariate logistic regression. Then, 4 RET mutation carriers were enrolled for prophylactic thyroidectomy, and their pathological data and follow-up outcomes were recorded. ResultsIn univariate and multivariate logistic regression analyses, age at initial surgery and risk classification were significant risk factors for stage III/IV hereditary MTC at initial diagnosis. The likelihood was increased by 11.6% per year of age at initial surgery [95% confidence interval (95% CI), 1.040–1.198; P=0.002). It was 7.888 times more likely to have III/IV stage disease for ATA highest risk patients, compared to ATA moderate risk individuals (95% CI, 1.607–38.717; P=0.003). Postoperative pathological results showed all 4 multiple endocrine neoplasia type 2A (MEN2A) patients had C-cell hyperplasia (CCH); multifocal malignancies were detected in 3 of them. All 4 patients were cured biochemically, and none developed permanent hypoparathyroidism.ConclusionsIn Chinese individuals, hereditary MTC aggressiveness is in line with the new ATA risk classification. Germline RET gene mutation carriers should undergo prophylactic thyroidectomy according to basal serum calcitonin levels.

Surgical Management of Medullary Thyroid Carcinoma in Pediatric Age.

Medullary thyroid carcinoma (MTC) is a rare, accounting for 5% of thyroid malignancies. It is a neuroendocrine tumor wich origins from thyroid parafollicular cells. It may be sporadic, mostly in adult patients, or inherited as autosomal dominant pattern, mostly in pediatric patients. As familial cancer, MTC may presented isolated as familial medullary thyroid carcinoma (FMTC) - 10% of cases - or, most often, as part of multiple endocrine neoplasm type 2 (MEN 2A or MEN 2B) syndromes - 90% of cases. The therapy for sporadic or hereditary MTC is surgical resection and consists in total thyroidectomy associated with central compartment lymph nodal dissection; the radicality of this intervention is fundamental to obtain a definitive cure. Genetic screening in children of parents with MEN2 or FMTC has led to prophylactic total thyroidectomy. The type of prophylactic surgery required is focus of great attention, and it is reported that total thyroidectomy, central neck dissection associated with parathyroid autotransplantation is the proper management. In children, the recommended age of surgery based on genetic testing is 5 years for patients with MEN 2A and FMTC, and 1 year for children possessing the RET mutation responsible for MEN 2B. The surgical management changes depending on the type of codon mutated.

RET pro-oncogene and medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) originats from the parafollicular C cells of the thyroid, which is one of the most aggressive forms of thyroid malignancy with the poor prognosis. Hereditary MTC has multiple endocrine neoplasia types 1, 2A and 2B. The mutation of RET proto-oncogene has been identified as the main cause of MTC, and all mutations locate among the exons 5, 8, 10, 11, 13, 14, 15, and 16. Mutation analysis of the RET may provide a theoretical basis for the prevention, diagnosis and treatment of MTC.

Rare RET Variant p.D707E in a Chinese Pedigree with Hereditary Medullary Thyroid Carcinoma

Background: Hereditary medullary thyroid carcinoma (HMTC) is thought to be associated with germline mutations of the RET proto-oncogene. Methods: We detected RET proto-oncogene germline mutations from a pedigree with HMTC in the east of China and investigated the characteristics of these mutations in this pedigree and their correlation with HMTC by direct sequencing of all 21 exons in the RET gene of all 46 subjects. Results and Conclusion: (1) Thirteen types of RET gene variants were detected in this pedigree. Of these, p.F285S in exon 4, c.854_855CA in exon 4, and p.D707E in exon 11 are reported for the first time in our study. (2) Both linkage disequilibrium analysis and logistic regression analysis showed a significant correlation between the p.D707E variant and HMTC (LOD = 3.69, OR = 4.413, p = 0.000167), indicating that this variant is a risk factor for medullary thyroid carcinoma (MTC). (3) The single-nucleotide polymorphisms (SNP) G691S in exon 11 (rs1799939), S904S in exon 15 (rs1800863), and rs2075912 and rs2565200 in the 3′-untranslated region of the RET proto-oncogene are in complete linkage disequilibrium (D' = 1, r² = 1); no correlation of these SNP and MTC was observed in this pedigree. (4) No hot-spot mutation of the RET proto-oncogene was detected in this pedigree. We drew the conclusion that the heterozygous nonsynonymous variant p.D707E in the RET proto-oncogene is rare, but it is a risk factor for hereditary MTC.

A Brief Review on The Molecular Basis of Medullary Thyroid Carcinoma.

Approximately 5-10% of all thyroid cancers are medullary thyroid carcinomas (MTC). MTC is mainly sporadic in nature, but 20-30% of cases are hereditary. Genetic testing for hereditary MTC is very important for the patient and his family, but the patients must be receiving appropriate genetic counseling. About 98% of patients with hereditary MTC have germline mutations in exons 10, 11, 13, 14, 15, 16 and intron 16 of the REarrangement during transfection (RET) proto-oncogene, but the etiology of the more frequent sporadic form of MTC (sMTC) is not well understood. Recently, it has been reported that apparently sporadic MTC may involve point mutations in BRAF and RAS genes, with an overall prevalence of almost 10%. Also alteration and abnormal expression of miRNA has been described in MTC. In this review, we attempted to mention some mutations and molecular changes in sporadic and hereditary MTC pathogenesis.

Detection of Molecular Alterations in Medullary Thyroid Carcinoma Using Next-Generation Sequencing: an Institutional Experience.

Medullary thyroid carcinoma (MTC) harbors rearranged during transfection (RET) gene and rarely RAS gene mutations. The knowledge of the type of gene mutation in MTC is important to determine the treatment of the patients and the management of their family members. Targeted next-generation sequencing with a panel of 47 genes was performed in a total of 12 cases of sporadic (9/12) and hereditary MTC (3/12). Two of three hereditary MTCs had RET/C634R mutation, while the other one harbored two RET mutations (L790F and S649L). All the sporadic MTC had RET/M918T mutation except one case with HRAS mutation. Next-generation sequencing (NGS) can provide comprehensive analysis of molecular alterations in MTC in a routine clinical setting, which facilitate the management of the patient and the family members.

A rare germline mutation c.2752 A>G (p.M918V) in the RET protooncogene in a patient with medullary and papillary thyroid carcinomas in cervical lymph node metastases: a case report and review of the literature

We report a rare germline RET mutation c.2752 A>G (p.M918V) found in a 62-year-old man with synchronous medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) (follicular variant) in cervical lymph node metastases with significant predominance of MTC. DNA sequencing of six exons (10, 11, 13–16) of the RET protooncogene from peripheral blood leucocytes was performed to exclude hereditary MTC in our patient. Postoperative CT was 20 pg/ml (N = 2–6 pg/ml). Pheochromocytoma and hyperparathyroidism were excluded. Genetic analysis of first-degree relatives showed that one of them, the healthy eldest son (37 y.o.), was a carrier of rare ATG>GTG heterozygous mutation at position c.2752 of the protooncogene RET. A 96-year-old mother of the patient and his younger son have not this mutation. The proband`s father was not available. The mutation was not revealed in 100 unrelated normal individuals. The clinical history is presented.

Retrospective analysis of 140 cases of medullary thyroid carcinoma followed-up in a single institution.

Familial cases of medullary thyroid carcinoma (MTC) may be diagnosed by genetic screening, while in sporadic tumors the diagnosis relies mainly on fine-needle aspiration cytology. The aim of the present study was to determine the demographic, clinical and pathological characteristics of MTC patients followed-up at the Portuguese Institute of Oncology Francisco Gentil (Lisbon, Portugal). For that purpose, a retrospective analysis of 140 MTC patients diagnosed between 1990 and 2010 was performed. The results indicated that patients with hereditary MTC (11.4%) were significantly younger than patients with sporadic MTC. Of the latter, 34.3% had no clinical suspicion of MTC prior to surgery. The sensitivity of cytology and calcitonin (CT) assay in diagnosing MTC were 51.3 and 98.7%, respectively. All familial index cases and 69.0% of sporadic cases presented with advanced stage disease at the time of diagnosis, while 73.0% of familial MTC detected by genetic/pentagastrin screening were diagnosed at the early stage of the disease. Biochemical cure (BC) was achieved in 39.7% of patients and, of these, only 6.5% relapsed. The 5 and 10-year survival rates were 79.3 and 73.6%, respectively. Age >45 years (P=0.026), advanced stage at diagnosis (P<0.001) and absence of BC (P<0.001) were predictors of a worse prognosis on univariate analysis. However, when the patients detected by genetic/pentagastrin screening were excluded from the analysis, age was no longer a prognostic factor, although disease stage remained a significant prognostic factor. On multivariate analysis, BC was the only factor with a significant impact on prognosis (P=0.031). In addition, the present study confirmed that the majority of patients were diagnosed at advanced stages, and CT determination was observed to be more sensitive than cytology to diagnose MTC. Patients at early stages were more prone to achieve BC, which was a favorable prognostic factor. To the best of our knowledge, the present study reports for the first time that age at diagnosis is not a predictor of survival for patients with MTC when cases diagnosed by genetic/pentagastrin screening (who are usually young patients at the initial stages of the disease), are excluded from the analysis.