Hereditary medullary thyroid cancer: age-appropriate thyroidectomy improves disease-free survival

Two sisters diagnosed with familial paraganglioma syndrome type 1 (FPGL1) and multiple endocrine neoplasia type 2A (MEN2A)

BACKGROUND

In clinical practice, genetic testing has become standard for many cancerous diseases. While a diagnosis of a single hereditary syndrome is not uncommon, the coexistence of two genetic diseases, even with partially common symptoms, remains unusual. Therefore, targeted next-generation sequencing (NGS), along with genetic consultation and imaging studies, is essential for every patient with confirmed paraganglioma. In this report, we present two sisters diagnosed with multiple endocrine neoplasia type 2 (MEN2A) and familial paraganglioma syndrome type 1 (FPGL1).

CASE PRESENTATION

After presenting to the clinic with neck tumors persisting for several months, both patients underwent tumor removal procedures following imaging and laboratory studies. Pathological reports confirmed the diagnosis of paragangliomas. Subsequently, genetic testing, including NGS, revealed a mutation in the rearranged during transfection (RET) gene: the heterozygous change (c.2410G > A), (p.Val804Met), and a variant of the succinate dehydrogenase complex subunit D (SDHD) gene: (c.64 C > T), (p.Arg22Ter). Subsequently, thyroidectomy procedures were scheduled in both cases.

CONCLUSION

To the best of our knowledge, this is the first report presenting these two mutations in two related patients, resulting in distinctive genetic syndromes with similar manifestations. This underscores that although infrequent, multiple hereditary disorders may co-occur in the same individual.

Voltage-Gated Sodium Channel NaV1.7 Inhibitors with Potent Anticancer Activities in Medullary Thyroid Cancer Cells

Our results from quantitative RT-PCR, Western blotting, immunohistochemistry, and the tissue microarray of medullary thyroid cancer (MTC) cell lines and patient specimens confirm that VGSC subtype NaV1.7 is uniquely expressed in aggressive MTC and not expressed in normal thyroid cells and tissues. We establish the druggability of NaV1.7 in MTC by identifying a novel inhibitor (SV188) and investigate its mode of binding and ability to inhibit INa current in NaV1.7. The whole-cell patch-clamp studies of the SV188 in the NaV1.7 channels expressed in HEK-293 cells show that SV188 inhibited the INa current in NaV1.7 with an IC50 value of 3.6 µM by a voltage- and use-dependent blockade mechanism, and the maximum inhibitory effect is observed when the channel is open. SV188 inhibited the viability of MTC cell lines, MZ-CRC-1 and TT, with IC50 values of 8.47 μM and 9.32 μM, respectively, and significantly inhibited the invasion of MZ-CRC-1 cells by 35% and 52% at 3 μM and 6 μM, respectively. In contrast, SV188 had no effect on the invasion of TT cells derived from primary tumor, which have lower basal expression of NaV1.7. In addition, SV188 at 3 μM significantly inhibited the migration of MZ-CRC-1 and TT cells by 27% and 57%, respectively.

Prophylactic and Early Thyroidectomy in RET Germline Mutation Carriers in Pediatric and Adult Population: Long-Term Outcomes of a Series of 63 Patients

Prophylactic and early thyroidectomy in RET germline mutation carriers allows the removal of the thyroid before medullary thyroid carcinoma (MTC) develops, or while it is still confined to the gland. This study was aimed to assess the clinicopathological features in RET carriers according to the age at surgery and the long-term outcomes after prophylactic and early thyroidectomy. A retrospective analysis of 63 operated asymptomatic RET carriers diagnosed after familial genetic screening was performed. Twenty-one RET carriers were operated at pediatric (<18 yrs) and 42 at adult (≥18 yrs) age. Serum preoperative calcitonin levels were significantly lower in pediatric compared to adult patients (p = 0.04); moreover, adult RET carriers had a greater frequency of microMTC at pathology (p = 0.009). Permanent postoperative morbidity occurred in 9.5% of patients, without differences between the two groups. Biochemical postoperative cure was achieved in all patients. At a median follow-up of 14 years, all C-cell hyperplasia patients are disease-free; conversely, biochemical, and structural recurrence of disease occurred in three adults and one pediatric patient with microMTC. The independent predictive factors of MTC were the age at surgery, the preoperative calcitonin level and the RET mutational risk profile (p < 0.02). In conclusion, prophylactic and early thyroidectomy are safe and effective procedures in achieving definitive cure in most RET carriers. However, since recurrences may occur at long-term in case of microMTC, thyroidectomy should be possibly performed earlier to prevent microMTC development.

Medullary thyroid carcinoma in children: current state of the art and future perspectives

Medullary thyroid carcinoma (MTC) is a distinct type of malignant thyroid tumor in cell origin, biological behavior, and natural history. It accounts for 1.6% of all thyroid cancers and presents either sporadically or as a hereditary disease, the latter occurring as a part of multiple endocrine neoplasia (MEN) 2A and MEN2B syndromes or as a familial MTC disease with no other manifestations. The gene responsible for the hereditary form is the rearranged during transfection (RET) gene, a proto-oncogene located to human chromosome 10. Most pediatric MTC cases have been discovered after genetic testing investigations, leading to the concept of prophylactic surgery in presymptomatic patients. Therefore, the genetic status of the child, along with serum calcitonin levels and ultrasonographic findings, determine the appropriate age for prophylactic surgical intervention. Nevertheless, a diagnosis at an early stage of MTC warrants total thyroidectomy and central lymph node dissection with the addition of lateral/contralateral lymph node dissection depending on the tumor size, ultrasonographic evidence of neck disease, or calcitonin levels. Conversely, locally advanced/unresectable or metastatic MTC is primarily treated with multikinase inhibitors, while more specific RET inhibitors are being tested in clinical trials with promising results.

Cancer Genetic Counseling-Current Practice and Future Challenges

Cancer genetic counseling practice is rapidly evolving, with services being provided in increasingly novel ways. Pretest counseling for cancer patients may be abbreviated from traditional models to cover the elements of informed consent in the broadest of strokes. Genetic testing may be ordered by a cancer genetics professional, oncology provider, or primary care provider. Increasingly, direct-to-consumer testing options are available and utilized by consumers anxious to take control of their genetic health. Finally, genetic information is being used to inform oncology care, from surgical decision-making to selection of chemotherapeutic agent. This review provides an overview of the current and evolving practice of cancer genetic counseling as well as opportunities and challenges for a wide variety of indications in both the adult and pediatric setting.

Prophylactic thyroidectomy in multiple endocrine neoplasia type 2A in children: a single centre experience

Background To describe the complications and long-term results in patients with multiple endocrine neoplasia type 2A (MEN 2A) syndrome in whom a prophylactic thyroidectomy was performed, in relation to the recommendations of the American Thyroid Association (ATA). Methods A retrospective study of 14 patients with MEN 2A thyroidectomized between 2000 and 2017. We reviewed demographic, clinical, analytical and radiological data. Postoperative complications and long-term follow-up were analyzed. Results We treated eight boys and six girls with a median age of 5 years old (range 2-10). The predominant genetic mutation belonged to codon 634 (8/14, 57.14%). Total thyroidectomy (TT) without cervical lymphadenectomy was performed in all patients. A right upper parathyroidectomy was performed in one patient due to intraoperative suspicion of increased volume. Histological study revealed no alterations. Two patients presented transient hypocalcemia postoperatively and no patient had permanent hypocalcemia or nerve damage. Pathological anatomy confirmed medullary thyroid microcarcinoma in 5/14 patients: all carrying codon 634 mutation and three of them with preoperative basal calcitonin levels <20 pg/mL. No recurrences or metastases have been detected after a mean follow-up of 8 years. A patient with codon 634 mutation developed a unilateral pheochromocytoma at 25 years of age. No patient has presented hyperparathyroidism. Conclusions Prophylactic thyroidectomy without cervical lymphadenectomy is an effective and safe preventive treatment in patients with MEN 2A syndrome when it is performed by experienced surgeons in reference centers.

Bilateral Medullary Thyroid Carcinoma in a 3-Year-Old Female Patient with Multiple Endocrine Neoplasia 2A Syndrome Undergoing Prophylactic Thyroidectomy: Should Current Guidelines Be Revised?

BACKGROUND

Multiple endocrine neoplasia (MEN) 2A is an autosomal dominant disorder that results from a mutation in the RET proto-oncogene on chromosome 10. Almost all of the affected patients develop medullary thyroid carcinoma (MTC). The American Thyroid Association recommends prophylactic thyroidectomy in MEN 2A pediatric patients, with the age of the recommended thyroidectomy varying according to the codon mutation present.

OBJECTIVES

This report questions the reliability of the currently placed guidelines and whether the age threshold for prophylactic thyroidectomy in patients with known codon 634 mutations should be lowered, in parallel with an earlier evaluation of calcitonin levels in the serum.

METHODS

We report the preoperative diagnosis as well as operative and postoperative course of a 3-year-old female patient with MEN 2A (codon 634 mutation) who underwent prophylactic thyroidectomy. The postoperative histopathologic findings are presented and discussed.

RESULTS

Despite the prophylactic nature of the operation, in parallel with a borderline calcitonin increase in the serum, bilateral MTC was discovered on pathology.

CONCLUSION

It is likely that the current guidelines should be revised to recommend calcitonin screening and prophylactic thyroidectomy at an earlier age for MEN 2A patients with known codon 634 mutations.

Notch3 as a novel therapeutic target in metastatic medullary thyroid cancer

BACKGROUND

Medullary thyroid cancer portends poor survival once liver metastasis occurs. We hypothesize that Notch3 overexpression in medullary thyroid cancer liver metastasis will decrease proliferation and growth of the tumor.

METHODS

TT cells were modified genetically to overexpress Notch3 in the presence of doxycycline, creating the TT-Notch3 cell line. Mice were injected intrasplenically with either TT-Notch3 or control vector TT-TRE cells. Each cell line had 3 treatment groups: control with 12 weeks of standard chow, early DOX with doxycycline chow at day 0 and for 70 days thereafter, and late DOX with doxycycline chow at 8 weeks. Each animal underwent micro-computed tomography to evaluate for tumor formation and tumor quantification was performed. Animals were killed at 12 weeks, and the harvested liver was stained with Ki-67, hematoxylin and eosin, and Notch3.

RESULTS

Induction of Notch3 did not prevent formation of medullary thyroid cancer liver metastases as all mice in the early DOX group developed tumors. However, induction of Notch after medullary thyroid cancer liver tumor formation decreased tumor size, as seen on micro-computed tomography scans (late DOX group). This translated to a 37-fold decrease in tumor volume (P = .001). Notch3 overexpression also resulted in decreased Ki-67 index (P = .038). Moreover, Notch3 induction led to increased areas of neutrophil infiltration and necrosis on hematoxylin and eosin staining of the tumors CONCLUSION: Notch3 overexpression demonstrates an antiproliferative effect on established metastatic medullary thyroid cancer liver tumors and is a potential therapeutic target in treatment.

Diagnosis and Management of Hereditary Phaeochromocytoma and Paraganglioma

About 30% of phaeochromocytomas or paragangliomas are genetic. Whilst some individuals will have clinical features or a family history of inherited cancer syndrome such as neurofibromatosis type 1 (NF1) or multiple endocrine neoplasia 2 (MEN2), the majority will present as an isolated case. To date, 14 genes have been described in which pathogenic mutations have been demonstrated to cause paraganglioma or phaeochromocytoma . Many cases with a pathogenic mutation may be at risk of developing further tumours. Therefore, identification of genetic cases is important in the long-term management of these individuals, ensuring that they are entered into a surveillance programme. Mutation testing also facilitates cascade testing within the family, allowing identification of other at-risk individuals. Many algorithms have been described to facilitate cost-effective genetic testing sequentially of these genes, with phenotypically driven pathways. New genetic technologies including next-generation sequencing and whole-exome sequencing will allow much quicker, cheaper and extensive testing of individuals in whom a genetic aetiology is suspected.

HABP2 Gene Mutations Do Not Cause Familial or Sporadic Non-Medullary Thyroid Cancer in a Highly Inbred Middle Eastern Population

BACKGROUND

Familial non-medullary thyroid cancer (NMTC) occurs either as part of known hereditary syndromes or as a non-syndromic isolated hereditary tumor. Although the genes underlying the syndromic type of NMTC have been identified in most syndromes, no clear underlying gene has been identified in the non-syndromic NMTC. Recently, a c.1601G>A, p.G534E mutation in the HABP2 gene was reported to be the underlying genetic defect in a family with seven members affected by NMTC. The G534E variant has also been reported to occur in about 4.7% of cases of the Thyroid Cancer Genome Atlas (TCGA) database.

OBJECTIVES

The aim of this study was to explore whether the recent finding of G534E genetic variant can be replicated in a large sample of NMTC, including 11 members of four unrelated families with familial NMTC and 509 cases of sporadic pediatric (63 cases) and adult NMTC (446 cases).

METHODS

All exons and exon-intron boundaries of HABP2 were screened in 11 members of four families with familial non-syndromic NMTC using DNA isolated from peripheral leucocytes, polymerase chain reaction, and direct sequencing. The G534E variant was also screened for specifically in 229 cases of sporadic NMTC using DNA isolated from peripheral leucocytes and an additional 217 cases of NMTC using DNA isolated from formalin-fixed paraffin-embedded tumor tissues. As a control cohort, 190 healthy individuals without known thyroid disease were also studied for the presence of the G534E variant using DNA isolated from peripheral leucocytes.

RESULTS

None of the familial NMTC carried HABP2 mutations. Of 509 sporadic NMTC, only one case (0.2%) harbored the G534E variant. Similarly, only one case (0.5%) of the control group harbored the G534E variant.

CONCLUSION

In this study, HABP2 mutations were not found in familial NMTC, and the G534E variant is not the underlying genetic defect in a large sample of sporadic NMTC from the Middle East.

Bilaterality weighs more than unilateral multifocality in predicting prognosis in papillary thyroid cancer

Papillary thyroid cancer (PTC) often presents as multifocal tumor;, however, whether multifocality is associated with poor prognosis remains controversial. The aims of this retrospective study were to identify the characteristics of PTC with multifocal tumors and evaluate the association between the location and prognosis. We reviewed the medical records of 496 patients who underwent total thyroidectomy for PTC. Patients were classified as three groups: N1 (solitary tumor), N2 (2 or more foci within unilateral lobe of thyroid), and N3 (bilateral tumors, at least one tumor focus for each lobe of thyroid). We analyzed the differences of clinicopathologic features and clinical outcomes among the three groups. Cox regression model was used to assess the relation between the different locations of multifocal tumors and prognosis. Although the differences of clinicopathologic features such as the size of tumor, extrathyroidal extension, and cervical lymph node metastasis were not significant among the three groups, the bilateral-multifocality was proved to be an independent risk factor for neck recurrence (hazard ratio (HR) = 4.052, 95 % confidence interval (CI) 2.070-7.933), distant metastasis (HR = 3.860, 95 % CI 1.507-9.884), and cancer death (HR = 7.252, 95 % 2.189-24.025). In addition, extrathyroidal extension (HR = 2.291, 95 % CI 1.185-4.427) and older age >45 years (HR = 6.721, 95 % CI 2.300-19.637) were also significant predictors for neck recurrence and cancer death, respectively. Therefore, bilateral-multifocality as an indicator for more extensive tumor location could be used to assess the risk of recurrence and mortality in PTC. Given the poor prognosis associated with bilateral-multifocality and other risk factors, aggressive therapy and intensive follow-up were recommended for PTC patients with them.

Surgery for lymph node metastases of medullary thyroid carcinoma: A review

Medullary thyroid carcinoma (MTC) is a neuroendocrine malignancy of the thyroid C cells that occurs in hereditary and sporadic clinical settings. Metastatic spread commonly occurs to cervical and mediastinal lymph nodes. MTC cells do not concentrate radioactive iodine and are not sensitive to hormonal manipulation, and therefore surgery is the most effective option for curative therapy, reduction in tumor burden, or effective palliation. In patients undergoing preventative surgery for hereditary MTC, central lymph node dissection should be considered if the calcitonin level is elevated. Preservation of parathyroid function in these young patients is of paramount importance. In patients with established primary tumors, systematic surgical removal of lymph node basins (compartmental dissection) should be guided by ultrasound mapping of lymph node metastases and level of serum calcitonin. A "berry-picking" approach is discouraged. Newly approved targeted molecular therapies offer wider treatment options for patients with progressive or metastatic disease.

Surgery for lymph node metastases of medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is a neuroendocrine malignancy of the thyroid C cells, and can commonly spread to cervical and mediastinal lymph nodes. MTC cells do not concentrate radioactive iodine and are not sensitive to hormonal manipulation, and therefore surgery is the only effective option for curative therapy, reduction in tumor burden or effective palliation. In patients undergoing preventative operations for hereditary MTC, central lymph node dissection should be considered if the calcitonin level is above 40 pg/ml. Systematic removal of at-risk or involved lymph node compartments should be performed in all patients with palpable primary tumors and recurrent disease, and a ‘berry-picking’ approach should be avoided.

Synergistic antitumour activity of RAF265 and ZSTK474 on human TT medullary thyroid cancer cells

Medullary thyroid cancer (MTC) is an aggressive malignancy responsible for up to 14% of all thyroid cancer-related deaths. It is characterized by point mutations in the rearranged during transfection (RET) proto-oncogene. The activated RET kinase is known to signal via extracellular signal regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K), leading to enhanced proliferation and resistance to apoptosis. In the present work, we have investigated the effect of two serine/threonine-protein kinase B-Raf (BRAF) inhibitors (RAF265 and SB590885), and a PI3K inhibitor (ZSTK474), on RET-mediated signalling and proliferation in a MTC cell line (TT cells) harbouring the RETC634W activating mutation. The effects of the inhibitors on VEGFR2, PI3K/Akt and mitogen-activated protein kinases signalling pathways, cell cycle, apoptosis and calcitonin production were also investigated. Only the RAF265+ ZSTK474 combination synergistically reduced the viability of treated cells. We observed a strong decrease in phosphorylated VEGFR2 for RAF265+ ZSTK474 and a signal reduction in activated Akt for ZSTK474. The activated ERK signal also decreased after RAF265 and RAF265+ ZSTK474 treatments. Alone and in combination with ZSTK474, RAF265 induced a sustained increase in necrosis. Only RAF265, alone and combined with ZSTK474, prompted a significant drop in calcitonin production. Combination therapy using RAF265 and ZSTK47 proved effective in MTC, demonstrating a cytotoxic effect. As the two inhibitors have been successfully tested individually in clinical trials on other human cancers, our preclinical data support the feasibility of their combined use in aggressive MTC.

Tumor-suppressor role of Notch3 in medullary thyroid carcinoma revealed by genetic and pharmacological induction

Notch1-3 are transmembrane receptors that appear to be absent in medullary thyroid cancer (MTC). Previous research has shown that induction of Notch1 has a tumor-suppressor effect in MTC cell lines, but little is known about the biologic consequences of Notch3 activation for the progression of the disease. We elucidate the role of Notch3 in MTC by genetic (doxycycline-inducible Notch3 intracellular domain) and pharmacologic [AB3, novel histone deacetylase (HDAC) inhibitor] approaches. We find that overexpression of Notch3 leads to the dose-dependent reduction of neuroendocrine tumor markers. In addition, Notch3 activity is required to suppress MTC cell proliferation, and the extent of growth repression depends on the amount of Notch3 protein expressed. Moreover, activation of Notch3 induces apoptosis. The translational significance of this finding is highlighted by our observation that MTC tumors lack active Notch3 protein and reinstitution of this isoform could be a therapeutic strategy to treat patients with MTC. We demonstrate, for the first time, that overexpression of Notch3 in MTC cells can alter malignant neuroendocrine phenotype in both in vitro and in vivo models. In addition, our study provides a strong rationale for using Notch3 as a therapeutic target to provide novel pharmacologic treatment options for MTC.

Number of tumor foci predicts prognosis in papillary thyroid cancer

Background

Papillary thyroid cancer (PTC) often presents as multifocal. However, the association of multifocality with poor prognosis remains controversial. The aim of this retrospective study was to identify the characteristics of PTC with multiple foci and to evaluate the association between multifocality and prognosis.

Methods

We reviewed the medical records of 496 patients who underwent total thyroidectomy for PTC. Patients were classified as G1 (1 tumor focus), G2 (2 foci), and G3 (3 or more foci). We analyzed the clinicopathological features and clinical outcomes in each classification. A Cox regression model was used to assess the relationship between multifocality and recurrence or cancer mortality.

Results

The G1, G2 and G3 groups included 287, 141 and 68 patients, respectively. The mean age was 47.1 ± 16.1 yr in G1, 41.1 ± 18.4 yr in G2, and 35.5 ± 15.9 yr in G3 and differed significantly among the 3 groups (p = 0.001). The proportion of extrathyroidal extension, central lymph node metastasis (CLNM), and lateral lymph node metastasis (LLNM) in the G1 to G3 groups increased with increasing number of tumor foci. The Kaplan–Meier curves revealed that G3 had the shortest recurrence-free survival, and differences were significant among the 3 groups (p = 0.001, Log Rank test). Furthermore, cancer-specific survival rates decreased significantly with increasing number of tumor foci (p = 0.041). Independent predictors of recurrence by multivariate Cox analysis included >3 tumor foci [HR 2.60, 95% confidence interval (CI) 1.53-4.39, p = 0.001] and extrathyroidal extension (HR 1.95, CI 1.12-3.38, p = 0.018).

Conclusion

An increase in the number of tumors is associated with a tendency toward more aggressive features and predicts poor prognosis in PTC.

The value of genetic screening in medullary thyroid cancer

Medullary thyroid cancer (MTC) accounts for ~10% of thyroid carcinomas and occurs in sporadic and hereditary forms. Early diagnosis significantly impacts the clinical course, management and outcome of the disease. The identification of germline-activating mutations of the rearranged during transfection oncogene in patients with hereditary MTC led to significant progress in the diagnostic and therapeutic approach, thus improving the quality of care provided, and consequently, disease prognosis. In the present review, various aspects of genetic screening (GS) in MTC will be covered, which elucidate the value of GS in guiding clinical decision making, therapy selection and appropriate genetic counseling of the affected families. GS should be offered to every MTC patient, based on the personal and family medical history, to allow optimal clinical management and follow-up.

Current understanding and management of medullary thyroid cancer

Medullary thyroid cancer (MTC) typically accounts for 3%-4% of all thyroid cancers. Although the majority of MTCs are sporadic, 20% of cases are hereditary. Hereditary MTC can be found in multiple endocrine neoplasia 2A or 2B or as part of familial MTC based on a specific germline mutation in the RET proto-oncogene. This article discusses the current approaches available for the diagnosis, evaluation, and management of patients and their family members with suspected MTC. The disease is predominantly managed surgically and typically requires a total thyroidectomy and lymph node dissection. A review of recent guidelines on the extent and timing of surgical excision is discussed. There are not very many effective systemic treatment options for MTC, but several emerging therapeutic targets have promise.