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Objective: Calcitonin and carcinoembryonic antigen (CEA) doubling times are established prognostic markers in medullary thyroid cancer (MTC). On the other hand, 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) shows an increased rate of detection with high blood tumor marker levels in several cancers. This study aimed to analyze the ability of 18F-FDG PET/CT to determine prognosis in the follow-up of patients with MTC. Methods: Medical records of 17 patients with MTC who underwent 18F-FDG PET/CT were analyzed retrospectively. All patients were classified into two groups: stable disease or progressive disease. Results: Eight patients presented with progressive disease, and all of them showed 18F-FDG uptake (100%), compared to only 3 of 9 patients who presented in stable condition (33%). 18F-FDG PET/CT results were able to distinguish progressive from stable disease (P = .009). Calcitonin levels >4,020 pg/mL (P = .0004), CEA levels >26.8 ng/mL (P = .04), and a calcitonin doubling time Conclusion:18F-FDG uptake was able to distinguish progressive from stable disease. However, this tool should not replace the validated calcitonin doubling time, but rather the combination of information could improve the clinical re-assessment and better identify high-risk patients who require more careful surveillance. Abbreviations: CEA = carcinoembryonic antigen CT = computed tomography 18F-FDG = 18F-fluorodeoxyglucose MTC = medullary thyroid cancer PET = positron emission tomography PVE = proportion of variance explained sCT = serum calcitonin SUV = standard uptake value US = ultrasound

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant genetic disease caused by RET gene germline mutations that is characterized by medullary thyroid carcinoma (MTC) associated with other endocrine tumors. Several reports have demonstrated that the RET mutation profile may vary according to the geographical area. In this study, we collected clinical and molecular data from 554 patients with surgically confirmed MTC from 176 families with MEN2 in 18 different Brazilian centers to compare the type and prevalence of RET mutations with those from other countries. The most frequent mutations, classified by the number of families affected, occur in codon 634, exon 11 (76 families), followed by codon 918, exon 16 (34 families: 26 with M918T and 8 with M918V) and codon 804, exon 14 (22 families: 15 with V804M and 7 with V804L). When compared with other major published series from Europe, there are several similarities and some differences. While the mutations in codons C618, C620, C630, E768 and S891 present a similar prevalence, some mutations have a lower prevalence in Brazil, and others are found mainly in Brazil (G533C and M918V). These results reflect the singular proportion of European, Amerindian and African ancestries in the Brazilian mosaic genome.

Objective Staging systems applied to medullary thyroid cancer (MTC) rely on initial clinical and pathological features and do not consider the response to treatment. To determine whether MTC staging can be improved by incorporating the first postoperative calcitonin measurement. Patients and measurements Eighty-five patients being monitored for MTC (median follow-up 5 years) were retrospectively classified according to both the American Joint Committee on Cancer (AJCC) and the proposed combined risk stratification system (low, intermediate and high risk), which incorporates the first postoperative calcitonin measurement, using the outcomes no evidence of disease (NED), biochemical evidence of disease, structurally identifiable disease and death. Results Ninety per cent of AJCC I patients were classified as NED at final follow-up. When we added a postoperative calcitonin measurement, 95% low-risk patients were classified as NED at final follow-up. AJCC stages I and IV were associated, respectively, with no occurrence and a high rate (63%) of structurally identifiable disease. Stages II and III yielded similar predictions of structurally identifiable disease, 13% and 14%, respectively. When we included the postoperative calcitonin level, the patients with structural evidence of disease included none from the low-risk group, 10% from the intermediate group and 63% from the high-risk group. The proportion of variance explained analysis (PVE) was better for the combined risk stratification system (54%) than for the AJCC system alone (32%). Conclusion Including the first postoperative calcitonin measurement with the anatomical staging system can better predict the clinical outcome of patients with MTC and refine the follow-up of these patients.

SummaryObjective Reviewing the clinical outcomes of a large kindred with a RET p.Gly533Cys mutation, 10 years after the first description of this kindred, has provided an important set of clinical data for healthcare decision-making. Design and Patients We identified 728 RET533 Brazilian relatives, spread out over 7 generations. We performed clinical examination, biochemical and imaging analyses in the proband and in 103 carriers. Measurement and Results The proband has been followed without evidence of structural disease in the last 10 years but with elevated calcitonin. The clinical and surgical features of 60 thyroidectomized RET533 relatives were also described. Forty-six patients had MTC (21–72 years), and 11 patients had C-cell hyperplasia (CCH) (5–42 years). Twelve MTC patients with lymph node metastases had a tumour size of 0·7–2·8 cm. Calcitonin level and CEA were correlated with disease stage, and none of the patients presented with an altered PTH or metanephrine. A 63-year-old woman developed pheochromocytoma and breast cancer. Two other RET533 relatives developed lung squamous cell carcinoma and melanoma. Conclusions A vast clinical variability in RET533 presentation was observed, ranging from only an elevated calcitonin level (3%) to local metastatic disease (25%). Many individuals were cured (42%) and the majority had controlled chronic disease (56%), reinforcing the need for individualized ongoing risk stratification assessment. The importance of this update relies on the fact that it allows us to delineate the natural history of RET 533 MEN2A 10 years after its first description.

Serum calcitonin (sCT) is the main tumor marker for medullary thyroid cancer (MTC), but it has certain limitations. Various sCT assays may have important intra-assay or interassay variation and may yield different and sometimes conflicting results. A pentagastrin- or calcium-stimulation calcitonin (CT) test may be desirable in some situations. Alternatively, or in the absence of the stimulation test, mRNA detection offers the advantages of being more comfortable and less invasive; it only requires blood collection and has no side effects. The objective of this study was to investigate the applicability of measuring calcitonin-related polypeptide alpha (CALCA) gene transcripts (CT-CALCA and calcitonin gene-related peptide [CGRP]-CALCA) in patients with MTC and in relatives diagnosed with a RET mutation and to test mRNA as an alternative diagnostic tool for the calcitonin-stimulation test.Twenty-three healthy controls and 26 individuals evaluated for MTC were selected, including patients with sporadic or hereditary MTC and RET mutation-carrying relatives. For molecular analysis, RNA was extracted from peripheral blood, followed by cDNA synthesis using 3.5 μg of total RNA. Quantitative real-time polymerase chain reaction (RT-qPCR) was performed with SYBR Green and 200 nM of each primer for the two specific mRNA targets (CT-CALCA or CGRP-CALCA) and normalized with the ribosomal protein S8 as the reference gene.We detected CALCA transcripts in the blood samples and observed a positive correlation between them (r=0.946, p0.0001). Both mRNAs also correlated with sCT (CT-CALCA, r=0.713, p0.0001; CGRP-CALCA, r=0.714, p0.0001). The relative expression of CT-CALCA and CGRP-CALCA presented higher clinical sensitivity (86.67 and 100, respectively), specificity (97.06 and 97.06), positive predictive value (92.86 and 93.75), and negative predictive value (94.29 and 100), than did sCT (73.33, 82.35, 64.71, and 87.50, respectively). In addition, the CALCA transcript measurement mirrored the response to the pentagastrin test.We demonstrate that the measurement of CALCA gene transcripts in the bloodstream is feasible and may refine the management of patients with MTC and RET mutation-carrying relatives. We propose considering the application of this diagnostic tool as an alternative to the calcitonin-stimulation test.

RET sequencing has become an important tool in medullary thyroid cancer (MTC) evaluation and should be performed even in the absence of family history of MTC. The most commonly studied exons in index cases are 8, 10, 11, and 13–16. To address the ATA guidelines regarding the sequencing of the entire coding region of RET, we selected 50 patients with sporadic MTC (sMTC) without mutations in the hot spot regions of RET for extended investigation of exons 1–7, 9, 12, 17, 18, and 19. Twenty-seven of 50 patients presented with one or more features suggesting familial disease. We found only a new RET variant (p.Gly550Glu) in one patient with MTC. Several polymorphisms were observed, and their frequency was histogram scaled by exons and introns. Eight patients were also included for somatic mutation search. We estimated the sequencing cost by stratifying into four investigation approaches: (1) hot spot exons in a new patient, (2) the remaining exons if the hot spots are negative in a patient with suspected familial disease, (3) a relative of a carrier for a known RET mutation, and (4) tumor sequencing. In spite of the increasing number of variants being described in MTC, it appears that there is no direct clinical benefit in extending RET germ line analysis beyond the hot spot regions in sMTC. The cost evaluation in apparent sMTC using a tiered approach may help clinicians make more suitable decisions regarding the benefits of investigating only the hot spots against the entire coding region of RET.

BACKGROUND: The hereditary form of medullary thyroid carcinoma may occur isolated as a familial medullary thyroid carcinoma (FMTC) or as part of Multiple Endocrine Neoplasia 2A (MEN2A) and 2B (MEN2B). MEN2B is a rare syndrome, its phenotype may usually, but not always, be noted by the physician. In the infant none of the MEN2B characteristics are present, except by early gastrointestinal dysfunction caused by intestinal neuromas. When available, genetic analysis confirms the diagnosis and guides pre-operative evaluation and extent of surgery. Here we report four cases of MEN2B in which the late diagnosis had a significant impact in clinical evolution and, potentially, in overall survival. CASE REPORT: We report four cases, 2 men and 2 women, with differences in their phenotypes and with a late diagnosis. The first case has a history of severe gastrointestinal obstruction requiring a surgery intervention two days after his birth. The second told had nodules in the oral mucosa and constipation since childhood. The third case referred a history of constipation from birth until 5 months of life. The fourth has had a history of chronic constipation since childhood. DISCUSSION: New concepts have emerged since the RET oncogene was identified in 1993 as the responsible gene for hereditary medullary thyroid carcinoma. The majority of MEN2B individuals have M918T mutation in the exon 16 of RET, with a few cases having a mutation A883F or the association of V804M with E805K, Y806C or S904C mutations. The consensus classifies the RET mutation in codon 918 as of highest risk and recommends total thyroidectomy and central lymph node dissection until 6 months after birth. A fast and precise diagnosis is essential to reach these goals. The identification of early manifestations such as intestinal ganglioneuromatosis and oral mucosal neuromas should prompt the physician to initiate an investigation for multiple endocrine neoplasia type 2B. CONCLUSION: The diagnosis of MEN2B is very important to allow appropriate investigation of associated diseases and to allow counseling and appropriate screening of relatives for a RET mutation. Even patients with MEN2B, which often have typical physical features, may not be properly recognized and be followed as a sporadic case. Based on this, all suspicious cases of multiple endocrine neoplasia should undergo a molecular genetic test. A forma hereditária do carcinoma medular da tiróide pode ocorrer de modo isolado, o carcinoma medular da tiróide familiar (FMTC), ou como parte das neoplasias endócrinas múltiplas tipo 2A (MEN2A) e 2B (MEN2B). MEN2B é uma síndrome rara e seu fenótipo é usualmente, mas nem sempre, notado pelo médico. Na infância, nenhuma das características de MEN2B estão presentes, exceto pela disfunção gastrintestinal precoce, causada pelos neuromas intestinais. Quando disponível, a análise genética confirma o diagnóstico e orienta a avaliação pré-operatória e extensão da cirurgia. Neste artigo, apresentamos quatro casos de MEN2B, nos quais o diagnóstico tardio teve impacto significativo na evolução clínica e, potencialmente, na mortalidade em geral. APRESENTAÇÃO DOS CASOS: Apresentamos quatro casos, dois homens e duas mulheres, com diferenças em seus fenotipos e com diagnóstico tardio. O primeiro caso tem história de obstrução gastrintestinal importante em que foi necessária cirurgia dois dias após o nascimento. O segundo paciente apresentava nódulos na mucosa oral e constipação desde a infância. O terceiro referia história de constipação desde o nascimento até 5 meses de idade. O quarto tinha história de constipação intestinal desde a infância. DISCUSSÃO: Novos conceitos emergiram desde que o oncogene RET foi identificado, em 1993, como o gene responsável pelo carcinoma medular da tiróide hereditário. A maioria dos indivíduos apresenta a mutação M918T no éxon 16 do RET, enquanto poucos casos apresentam a mutação A883F ou a associação de V804M com E805K, Y806C ou S904C. O consenso recomenda a tiroidectomia total com dissecção dos linfonodos no compartimento central até os 6 meses após o nascimento. O diagnóstico rápido e preciso é essencial para o atingir os objetivos. CONCLUSÃO: O diagnóstico precoce de MEN2B é muito importante para propiciar a investigação apropriada de doenças associadas e para permitir aconselhamento e rastreamento dos parentes para uma mutação do RET. Pacientes com MEN2B, que apresentam frequentemente achados típicos ao exame físico, podem não ser reconhecidos e seguidos como casos esporádicos. Por causa disso, todos os casos de neoplasia endócrina múltipla devem ser avaliados pelo teste genético para mutações do RET.

Background: Tumor-associated macrophages (TAMs) are alternatively activated or M2 macrophages that infiltrate cancer tissues. It has been suggested that TAMs exert several pro-tumor functions by releasing several growth factors and proangiogenic cytokines that favor tumor progression. In fact, TAM density has been associated with poor prognosis. Although it is well known the pro-tumor roles of TAM in several tumor types, its role in medullary thyroid cancer (MTC) is still unknown. We here evaluated the M2 macrophage marker CD163 in MTC and correlated with RET mutational status and clinical and pathological features. Because it has been suggested TAMs could interact with CD44-positive tumor cells to during tumorigenesis process, we also investigated the expression of CD44 in MTC. Patients and Methods: CD163 and CD44 expression we investigated in 78 MTC by immunohistochemistry (IHC). Because hereditary form is caused by germline mutations in the RET gene, all patients were screened for RET mutations (exons 8, 10, 11, 13-16) in the DNA isolated from blood samples. Those MTC that were negative for RET germline mutations, were also screened for somatic mutations in the RET gene (exons 10, 11 e 16). Results: Germline mutation in the RET gene were identified in 29 patients (p.G533C, p.C609Y, p.C611Y, p.C620Y, p.C634R, p.C634Y/Y791F, p.S891A and p.M918V). Approximately 49 cases are sporadic cases in which somatic RET mutations were identified in about 6 cases (p.M918T, p.C634R and p.C634Y). CD163 expression was mainly found in sporadic MTC when compared to hereditary MTC (p=0.021), suggesting that TAM may play a role in the progression of sporadic MTC. On the other hand CD44 expression was mainly found in hereditary MTC than in sporadic cases (p=0.017), particularly in patients with RET germlime mutation at codon C634. Conclusion: TAM seems to be more important for sporadic MTC tumorigenesis when compared to hereditary MTC. On the other hand, CD44 expression correlated with hereditary MTC, particularly in patients with mutation at codon C634. Citation Format: MARTA MIYAZAWA, MARIA JOSE C. P. SANTOS, LARISSA V. BIM, ERIKA S. L. ORTI-RADUAN, FLÁVIA O. F. VALENTE, ADAUTO F. NUNES, ROSANA DELCELO, RUI M. B. MACIEL, JANETE M. CERUTTI. TAM and CD44 in medullary thyroid carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1072. doi:10.1158/1538-7445.AM2014-1072