Cases Of Sporadic Medullary Thyroid Carcinoma Research Articles

Risk factors of recurrence or metastasis in patients with medullary thyroid carcinoma

Objective: To analyze the risk factors of recurrence or metastasis of medullary thyroid carcinoma (MTC) and the influencing factors of disease-free survival (DFS). Methods: The clinicopathological data of MTC patients who visited Tianjin Medical University Cancer Institute and Hospital and underwent surgery from August 2014 to August 2019 were retrospectively analyzed. The patients were divided into recurrence or metastasis group and no recurrence or metastasis group. Multivariate logistic regression analysis was used to analyze the risk factors for recurrence or metastasis. Kaplan-Meier survival analysis and Cox regression analysis were used to determine the risk factors of DFS. Results: A total of 158 MTC patients were enrolled in final analysis, including 83 females and 75 males, with a median age of 52 (19-74) years. There were 146 cases of sporadic MTC (92.4%) and 12 cases of familial MTC (7.6%), respectively. Bilateral thyroid lesions presented in 33 cases (20.9%) and multiple lesions presented in 57 cases (36.1%), respectively. The median follow-up time was 59.7 (10.0-93.0) months and the median DFS was 55.5 (0-92.9) months. Presence of multifocality, the largest tumor size>2 cm, T3/4, N1b, clinical stage Ⅲ/Ⅳ, lymph node metastasis ratio (LNR)>0.3, preoperative calcitonin>2 000 ng/L, postoperative calcitonin>40 ng/L and no biochemical cure were significantly correlated with the recurrence or metastasis and DFS of MTC (all P<0.05). Clinical stage Ⅲ/Ⅳ (OR=36.57, 95%CI: 1.33-1 006.98, P=0.033), the largest tumor size>2 cm (OR=5.81, 95%CI: 1.01-33.33, P=0.049), multifocality (OR=3.64, 95%CI: 1.03-12.88, P=0.045) and postoperative calcitonin>40 ng/L (OR=15.03, 95%CI: 1.39-162.61, P=0.026) were independent risk factors of recurrence or metastasis. Clinical stage Ⅲ/Ⅳ (HR=19.39, 95%CI:1.40-268.19, P=0.027), the largest tumor size>2 cm (HR=3.64, 95%CI: 1.02-13.02, P=0.047) and postoperative calcitonin>40 ng/L (HR=10.68, 95%CI: 1.34-84.95, P=0.025) were influencing factors for DFS (all P<0.05). Conclusion: The larger tumor size, advanced clinical stage and higher postoperative calcitonin at the initial treatment of MTC are risk factors for recurrence or metastasis and influencing factors for DFS.

Effects of rearranged during transfection mutation on calcitonin and procalcitonin expression in sporadic medullary thyroid carcinoma*

Abstract Objective The aim of this study was to investigate the effects of rearranged during transfection (RET) mutation on the expressions of calcitonin (CTn) and procalcitonin (PCT) in sporadic medullary thyroid carcinoma (SMTC). Methods RET mutation was detected by polymerase chain reaction direct sequencing in 64 cases of SMTC, and the expression levels of CTn and PCT in SMTC tissues were detected using the immunohistochemical streptavidin-perosidase (SP) method. The effect of RET mutations on the expression of CTn and PCT along with its relationship with clinicopathological parameters were analyzed. Results The expression rates of CTn and PCT in SMTC tissues were 90.6% (58/64) and 67.2% (43/64), respectively. CTn and PCT expression were found to be associated with tumor size and lymph node metastasis (P &lt; 0.05) but not with gender, age, or tumor capsule invasion (P &gt; 0.05). There was a significant correlation between CTn and PCT expression (r = 0.269, P = 0.041), and the intensity of positive CTn expression was positively correlated with RET mutation (r = 0.507, P = 0.000). However, PCT expression was not associated with RET mutation (r = 0.188, P = 0.136). Conclusion High expression of CTn and PCT was associated with the progression of medullary carcinoma, and the intensity of CTn expression was associated with RET mutation. PCT may provide valuable information for the diagnosis and prognosis of SMTC.

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.

Ret Oncogene and Thyroid Carcinoma

Thyroid cancer is a malignant neoplasm that originates from follicular or parafollicular thyroid cells and is categorized as papillary (PTC), follicular (FTC), anaplastic (ATC) or medullary thyroid carcinoma (MTC). The alteration of the Rearranged during trasfection (RET) (proto-oncogene, a gene coding for a tyrosine-kinase receptor involved in the control of cell differentiation and proliferation, has been found to cause PTC and MTC. In particular, RET/PTC rearrangements and RET point mutations are related to PTC and MTC, respectively. Although RET/PTC rearrangements have been identified in both spontaneous and radiation-induced PTC, they occur more frequently in radiation-associated tumors. RET/PTC rearrangements have also been reported in follicular adenomas. Although controversial, correlations between RET/PTC rearrangements, especially RET/PTC3, and a more aggressive phenotype and a more advanced stage have been identified. Germline point mutations in the RET proto-oncogene are associated with nearly all cases of hereditary MTC, and a strict correlation between genotype and phenotype has been demonstrated. A large spectrum of RET point mutations has been reported to date. Somatic RET mutations, almost all of which are point mutations, have been described in approximately 40-50% of sporadic MTC cases. Although RET somatic mutations have been found in different codons, the M918T mutation in exon 16 is the most frequent. Detecting germline RET point mutations is a useful tool for identifying subjects who are clinically unaffected but who will develop the disease soon or late in their life, thus allowing presymptomatic treatment. From a clinical point of view, detecting RET somatic mutations in tumoral tissue is able to predict a poor outcome of the disease. In recent years, several drugs capable of inhibiting RET activity have been demonstrated to play an important role in the treatment of radiorefractory advanced thyroid carcinomas.

The rare intracellular RET mutation p.Ser891Ala in an apparently sporadic medullary thyroid carcinoma: a case report and review of the literature

Medullary thyroid carcinoma (MTC) is a malignant tumor originating from parafollicular C-cells and accounts for 4-10% of all thyroid carcinomas. MTC develops in either sporadic (75%) or hereditary form (25%). Mutations in the RET proto-oncogene are responsible for hereditary MTC and the rate of heritable disease among apparently sporadic MTC (sMTC) cases varies from 6 to 15%. RET genetic testing is now considered fundamental in MTC management but the extent of the molecular analysis required to exclude inherited disease is still controversial. While the screening of all known mutation loci is recommended by some authors, the high costs associated with a full analysis should be also taken into consideration. Here, we illustrate and discuss this controversial issue by reporting a patient who present all characteristic features of sMTC, and in whom a standard genetic analysis by restriction enzyme restriction excluded hereditary disease. Nevertheless, an extensive molecular analysis that included all codons was prompted by the diagnosis of thyroid neoplasm in a patient's sister, and identified the rare intracellular RET p.Ser891Ala mutation.

Clinical characteristics of hereditary and sporadic medullary thyroid carcinoma.

To study the clinical characteristics and outcomes of the hereditary medullary thyroid carcinoma (HMTC) and the sporadic medullary thyroid carcinoma (SMTC). The clinical data of 78 patients with medullary thyroid carcinoma who underwent surgery in our hospital between July 1980 and May 2011 were retrospectively analyzed. Of these 78 patients, there were 23 HMTC cases and 55 SMTC cases. The HMTC group was significantly younger age of onset [(36.4±13.5) years vs. (46.6±11.2) years, P<0.01] and a lower pre/post-operative serum calcitonin levels [(850.4±110.20) ng/L vs. (1450.4±118.3) ng/L, P<0.01 and (410.8±133.2) ng/L vs. (1585.4±129.5) ng/L, P<0.01] than the SMTC group. In addition, the mean tumor diameter was also significantly smaller in the HMTC group (14.3 mm vs. 21.0 mm in SMTC group, P<0.05). Tumor multifocality was seen in a significantly higher proportion of HMTC cases compared with the SMTC cases (56.6% vs. 29.1%, P<0.05). The overall 10-year survival was 100% in HMTC group and 80.2% in SMTC group (P<0.05). HMTC has a better prognosis than SMTC.

Genetic alterations in a primary medullary thyroid carcinoma and its lymph node metastasis in a patient with 15 years follow-up

BackgroundAssociation between DNA alterations and clinical parameters as recurrence, survival or prognosis has been found in a variety of tumors. A clear association between Medullary Thyroid Carcinoma (MTC) and RET oncogene mutation has been accepted. Specifically M918T RET mutation represents the main genetic event in most cases of sporadic MTC (SMTC) and limited chromosomal alterations analyses have been performed.MethodsIn the present work, a comparative genomic hybridization (CGH) study was performed using DNA from a primary tumor in a M918T RET mutation-positive SMTC patient and from its lymph node metastasis to investigate additional genetic alterations. We studied a patient with 15 years of follow-up and persistence of disease, confirmed by periodical elevated serum calcitonin (CT) levels.ResultsOnly 3 chromosomal imbalances were identified in the primary tumor, gain of 18p, and loss of 6p and 16p region, whereas 25 chromosomal imbalances were identified in the metastasis (9 gains and 16 losses).ConclusionThe chromosomal changes 6p-, 16p-, 18p + could determine in part the oncogenic phenotype in the primary M918T RET positive tumor and probably related to persistence of high serum CT levels in this patient. The additional chromosomal changes observed could be related to the metastasis phenotype. We suggest that some genes mapped at 6p, 16p and 18p chromosomal regions, could act as genes associated to cancer and could be related to persistent SMTC and good prognosis.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1720753793691097

Beyond RET: potential therapeutic approaches for advanced and metastatic medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is a rare calcitonin-producing neuroendocrine tumour that originates from the parafollicular C-cells of the thyroid gland. The RET proto-oncogene encodes the RET receptor tyrosine kinase, which has essential roles in cell survival, differentiation and proliferation. Activating mutations of RET are associated with the pathogenesis of MTC and have been demonstrated in nearly all hereditary and in 30-50% of sporadic MTC cases, making this receptor an excellent target for small-molecule inhibitors for this tumour. Clinical trials of small organic inhibitors of tyrosine kinase receptors (TKIs) targeting the RET receptor have shown efficacy for treatment of metastatic MTC with 30-50% of patients responding to these agents. Despite the importance of the RET receptor in MTC, it is clear that other signal transduction pathways, tyrosine kinase receptors, and tumour suppressor genes are involved in MTC tumourigenesis and progression. A better understanding of molecular cross-talk between these signal pathways and the RET receptor may lead to combinatorial therapy that will improve outcomes beyond what is currently possible with RET-directed TKIs. Finally, there is evidence that immunological-based therapy using dendritic cell vaccination strategies have been effective for reducing tumour mass in a small number of patients. The identification of additional MTC-specific tumour antigens and a better understanding of specific epitopes in these tumour antigens may lead to improvement of response rates.

Occurrence of the Cys611Tyr mutation and a novel Arg886Trp substitution in the RET proto‐oncogene in multiple endocrine neoplasia type 2 families and sporadic medullary thyroid carcinoma cases originating from the central region of Portugal

Medullary thyroid carcinoma (MTC) occurs both sporadically and in the context of autosomal dominantly inherited multiple endocrine neoplasia type 2 (MEN2) syndromes: MEN2A, MEN2B, and familial medullary thyroid carcinoma (FMTC), which are caused by activating germline mutations in the RET proto-oncogene. The aim of this study was to characterize the RET mutational spectrum in MEN2 families and apparently sporadic MTC (AS-MTC) cases originating from the central region of Portugal. We studied a total of 82 individuals (64 affected and 18 family members), comprising five MEN2 families (four MEN2A and one MEN2B), as well as 53 AS-MTC cases. RET germline mutations were screened using PCR-DNA sequencing, SSCP and RFLP. The haplotypes associated with recurrent mutations were determined by fragment analysis of microsatellite markers, and by RFLP, in the case of intragenic polymorphisms. Frequency of the Cys611Tyr (TGC-TAC) mutation was significantly increased in this region of Portugal, due to the fact that three apparently unrelated MEN2A/FMTC families, out of the five in which mutations were identified, harboured this specific mutation. Haplotype analysis revealed that a common haplotype was shared between two of these three families. We have also characterized a novel RET mutation, Arg886Trp, located in the tyrosine kinase domain, which was found in an AS-MTC case. There are regional specificities in the relative frequency of RET mutations, which are consistent with a cluster-like distribution of specific disease-causing mutations, as a result of the inheritance of a shared haplotype. These data, along with the finding of a novel RET mutation (Arg886Trp), have important implications towards facilitating and improving the molecular diagnosis of hereditary MTC on a regional basis.

Galectin-3 expression in medullary thyroid carcinoma in relation to tumor progression

BACKGROUND: Galectin-3, a lectin with specificity for beta galactosides, is believed to be implicated in multiple biological processes through interactions with complementary glycoconjugates. Alterations in galectin-3 expression are observed in a variety of human tumors. In thyroid, this lectin has been found to be highly expressed in malignancies of epithelial origin. We analyzed galectin-3 expression in medullary thyroid carcinoma (MTC). MATERIALS AND METHODS: An immunohistochemical study using monoclonal antibody was performed on paraffin sections of twenty cases of sporadic MTC comprising ten cases without and ten cases with lymph node metastases at the time of surgery. RESULTS: Positive cytoplasmic staining for galectin-3 was found in 16/20 cases, but varied in intensity and distribution from weak/focal (7/16) to moderate (7/16) or strong (2/16). Advanced stage of MTC (with lymph node metastases at the time of surgery) showed moderate to strong galectin-3 expression more frequently (8/10) than cases without lymph node metastases (1/10). CONCLUSION: These findings suggest that galectin-3 expression is associated with the advanced stage of disease and that this lection might play a role in the pathobiology of MTC.

Three novel mutations in the RET proto-oncogene.

Medullary thyroid carcinoma (MTC) occurs as a sporadic tumor or in connection with inherited cancer syndromes of multiple endocrine neoplasia type 2 and familial MTC. Missense RET proto-oncogene mutations and small in-frame deletions are found in most of the cases. In a significant amount of sporadic MTC cases somatic mutation at codon 918 (exon 16), or at codons 609, 611, 618, 620 (exon 10), or codons 630, 634 (exon 11) appear. We report here on three new somatic cell missense mutations of the RET proto-oncogene associated with sporadic MTC. In one tumor mutation at codon 922 TCC(Ser)-->TTC(Phe) in exon 16 was found. In another tumor two mutations at codons 639 GCA(Ala)-->GGA(Gly) and 641 GCT(Ala)-->CGT(Arg) in the exon 11 were observed. Allele-specific PCR followed by sequencing demonstrated the presence of both mutations at the same allele.

Large-scale analysis of mutations in RET exon 16 in sporadic medullary thyroid carcinomas in Japan.

Germline mutations in the RET proto‐oncogene are the cause of multiple endocrine neoplasia type 2 (MEN 2A and 2B) and familial medullary thyroid carcinoma (FMTC). Some cases of sporadic medullary thyroid carcinoma (MTC) have also been reported to have mutations in the RET gene. However, two previous reports have given discrepant results on the frequency of the mutations in RET in sporadic MTCs in Japan. To clarify this problem, we analyzed mutations in RET exon 16 in 72 sporadic MTCs by means of the two methods used in the previous studies, direct sequencing and polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP). Mutations in exon 16 were detected in only 2 of 72 cases of sporadic MTC. These results suggest that when a MTC has a mutation in RET exon 16, it is more likely to be a hereditary MTC than a sporadic one in Japan.

Over-representation of a germline variant in the gene encoding RET co-receptor GFRalpha-1 but not GFRalpha-2 or GFRalpha-3 in cases with sporadic medullary thyroid carcinoma.

In contrast to the hereditary form of medullary thyroid carcinoma (MTC), little is known about the etiology of sporadic MTC. Somatic gain-of-function mutations in the RET proto-oncogene, encoding a receptor tyrosine kinase, are found in an average of 40% of sporadic MTC. We analysed 31 sporadic MTC for somatic and germline variants in GFRA1, GFRA2 and GFRA3 which encode the co-receptors of RET. Although there were no somatic mutations in any of the three genes, a sequence variant (-193C>G) in the 5'-UTR of GFRA1 was found in 15% of cases. Three patients were heterozygous (het); another three patients homozygous (hom) for the G variant. The G allele was not observed in 31 race-matched normal controls. Hence, the relative frequency of this variant in sporadic MTC cases and controls differed significantly (P<0.05). Since this variant lies in the 5' UTR, likely at the transcriptional start site, we analysed for differential expression of GFRalpha-1 at the transcript and protein levels. At the mRNA level, GFRA1 was over-expressed in tumors harboring the rare variant (P=0.06). The presence of the G polymorphic allele seemed to be associated with increased expression by immunostaining for GFRalpha-1. Interestingly, cytoplasmic staining was stronger in intensity for het patients and nuclear staining predominant in hom cases. In conclusion, mutation analysis of GFRA1, GFRA2 and GFRA3 revealed over-representation of a rare variant in GFRA1 (-193C>G) in the germline of sporadic MTC cases. Our data suggest that the mechanism is related to over-expression of GFRalpha-1 and differential subcellular compartmentalization but the precise mechanism as to how it acts as a low penetrance susceptibility allele for the development of sporadic MTC remains to be elucidated.

Galectin-3 and carcinoembryonic antigen expression in medullary thyroid carcinoma: possible relation to tumour progression.

Galectin-3 is a beta-galactoside binding protein involved in multiple biological processes through interactions with complementary glycoconjugates. We analysed the expression and coexpression of galectin-3 and carcinoembryonic antigen (CEA), one of the putative galectin-3 ligands, in medullary thyroid carcinoma (MTC). An immunohistochemical study using monoclonal antibodies was performed on paraffin sections of 20 cases of sporadic MTC comprising 10 cases without and 10 cases with lymph node metastases at the time of surgery. CEA expression was found in all tumours, distributed predominantly in the cytoplasm and occasionally at the cell surface. In the majority of cases (18/20) moderate to strong intensity of staining was found in most of the cells. Positive cytoplasmic staining for galectin-3 was found in 16/20 cases, but varied in intensity and distribution from weak/focal (7/16) to moderate (7/16) or strong (2/16). More intense staining for galectin-3 was mainly associated with MTC cases involving lymph node metastases. Eight out of these 10 cases showed moderate to strong galectin-3 expression concomitant with CEA expression throughout the tumour tissue. These findings suggest that galectin-3 might play a role in the pathobiology of MTC. Simultaneous expression of galectin-3 and CEA in the same tumour cells at an advanced stage of MTC indicates the possibility of their autocrine cooperation during tumour progression.

The RET proto-oncogene and cancer.

The RET proto-oncogene, a receptor tyrosine kinase, has been evaluated as a candidate gene for multiple endocrine neoplasia type 2A and type 2B (MEN 2A and MEN 2B), for familial medullary thyroid carcinoma (FMTC), and for sporadic cases of medullary thyroid carcinoma (MTC) and pheochromocytomas. We determined the genomic structure of RET and used single-strand conformational polymorphism (SSCP) analysis to identify sequence variants in genomic DNA from families segregating MEN 2 and FMTC. In addition, we examined paired tumour and lymphocyte genomic DNAs from individuals with sporadic cases of MTC and pheochromocytoma. Altogether, we and others found 21 missense mutations in five cysteines clustered in the extra-cellular domain of RET (exons 10 and 11) associated with 111 MEN 2A and FMTC families. In contrast, a single point mutation that results in the substitution of threonine for methionine within the catalytic core of the tyrosine kinase domain (codon 918, exon 16) is responsible for all 66 reported cases of MEN 2B. Two missense mutations and a six base-pair deletion were identified in MTC tumour DNA, but no mutations were identified from pheochromocytoma tumour DNAs. A predictive DNA test for MEN 2A-associated mutations in RET has been developed that is based on detection of missense mutations by polymerase chain reaction (PCR) amplification and restriction endonuclease cleavage. A dominant oncogene model for the action of the RET gene product is proposed as a mechanism of action in MEN 2A, MEN 2B, FMTC and for at least some cases of sporadic MTC.

Progress in genetic screening of multiple endocrine neoplasia type 2A: is calcitonin testing obsolete?

Recent identification of RET mutations in multiple endocrine neoplasia type 2A (MEN 2A) allows a DNA-based approach to diagnosis in lieu of calcitonin sampling. To prospectively evaluate the efficacy of mutational analysis, genetic screening was performed in 124 patients (53 male, 71 female; age, 1 month to 80 years) at risk for MEN 2A referred over 3 months. Analysis used genomic DNA and a polymerase chain reaction-based denaturing gradient gel electrophoresis strategy for mutation detection at RET codons 609, 611, 618, 620, and 634. Ninety-three of 124 patients were from established MEN 2A kindreds (group A), and screening replaced calcitonin testing. Twenty-one of 124 patients (group B) represented index cases of medullary thyroid carcinoma (MTC), and DNA analysis was performed to distinguish sporadic from hereditary disease. Ten patients (group C) had modest calcitonin elevations or had undergone thyroidectomy without confirming pathologic results, and testing was undertaken to clarify status. Group A: RET mutations occurred in 29 (median age, 10 years) of 93 patients, 14 of whom underwent thyroidectomy. No false-positive results were observed. Group B: five (24%) of 21 patients with seemingly sporadic MTC had RET mutations at codons 618 (one), 620 (one), or 634 (three). Group C: Nine of 10 patients with alleged MEN 2A had genetically negative results. Denaturing gradient gel electrophoresis reliably detects MEN 2A. Modest calcitonin elevations may lead to a false-positive diagnosis of MTC. DNA testing is the optimal approach to evaluating MEN 2A. Index cases of sporadic MTC should also undergo DNA analysis.