Thyroid Diseases: Gagel RF

Sherman SI, Angelos P, Ball DW, Byrd D, Clark OH, Daniels GH, Dilawari RA, Ehya H, Farrar WB, Gagel RF, Kandeel F, Kloos RT, Kopp P, Lamonica DM, Loree TR, Lydiatt WM, McCaffrey J, Olson JA, Ridge JA, Shah JP, Sisson JC, Tuttle RM, Urist MM, Anonymous00403. · The University of Texas M.D. Anderson Cancer Center, USA. · J Natl Compr Canc Netw. · Pubmed #17623612 No free full text.

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Sherman SI, Angelos P, Ball DW, Beenken SW, Byrd D, Clark OH, Daniels GH, Dilawari RA, Ehya H, Farrar WB, Gagel RF, Kandeel F, Kloos RT, Kopp P, Lamonica DM, Loree TR, Lydiatt WM, McCaffrey J, Olson JA, Ridge JA, Robbins R, Shah JP, Sisson JC, Thompson NW, Anonymous00251. · University of Texas M.D. Anderson Cancer Center, USA. · J Natl Compr Canc Netw. · Pubmed #16002006 No free full text.

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Cote GJ, Gagel RF. · No affiliation provided · N Engl J Med. · Pubmed #14561800 No free full text.

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Santarpia L, Ye L, Gagel RF. · The Department of Endocrine Neoplasia & Hormonal Disorders, The University of Texas MD Anderson Cancer Center, Houston, TX, USA. · J Intern Med. · Pubmed #19522829 No free full text.

Abstract: 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.

Jiménez C, Hu MI, Gagel RF. · Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas MD Anderson Cancer Center, Unit 435, 1515 Holcombe Boulevard, Houston, TX 77030-4009, USA. · Endocrinol Metab Clin North Am. · Pubmed #18502338 No free full text.

Abstract: Medullary thyroid carcinoma (MTC) is responsible for 13.4% of the total deaths attributable to thyroid cancer in human beings and research on MTC over the last 40 years has identified the RET proto-oncogene as a very relevant component of development of both sporadic and hereditary MTC. An activating germline RET proto-oncogene mutation responsible for a multiple endocrine neoplasia syndrome type 2 (MEN2) or a familial hereditary MTC syndrome is carried by 25% to 35% of patients with MTC. The recognition of RET proto-oncogene mutations by genetic sequencing has allowed us to differentiate hereditary from sporadic MTC, so that it is now possible to identify and treat children at risk for this disease before development of metastasis. Thanks to this discovery, we can now establish the association of MTC with other tumors in the context of MEN2 syndrome; determine adequate follow-up, prognosis, and treatment for patients with hereditary disease; and use this information to develop new therapies against both sporadic and hereditary MTCs.

Kouvaraki MA, Shapiro SE, Perrier ND, Cote GJ, Gagel RF, Hoff AO, Sherman SI, Lee JE, Evans DB. · Department of Surgical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77230-1402, USA. · Thyroid. · Pubmed #16029119 No free full text.

Abstract: Hereditary medullary thyroid carcinoma (MTC) is caused by autosomal dominant gain-of-function mutations in the RET proto-oncogene. Associations between specific RET mutations (genotype) and the aggressiveness of MTC and presence or absence of other endocrine neoplasms (phenotype) are well documented. Mutations in six exons (10, 11, 13, 14, 15, and 16) located in either cysteine-rich or tyrosine kinase domains cause one of three distinctive clinical subtypes: familial MTC, multiple endocrine neoplasia (MEN) type 2A (including variants with Hirschsprung's disease and cutaneous lichen amyloidosis), and MEN 2B. Hallmarks of MEN 2A include MTC, pheochromocytoma, and hyperparathyroidism. MEN 2B is associated with an earlier onset of MTC and pheochromocytoma, the absence of hyperparathyroidism, and the presence of striking physical stigmata (e.g., coarse facies, ganglioneuromatosis, and marfanoid habitus). Familial MTC is not associated with other endocrine neoplasms; however, the accurate distinction between familial MTC and MEN 2A may be difficult in kindreds with small size, incomplete histories, or a predominance of young individuals who may not have yet fully manifested the syndrome. Genetic testing detects greater than 95% of mutation carriers and is considered the standard of care for all first-degree relatives of patients with newly diagnosed MTC. Recommendations on the timing of prophylactic thyroidectomy and the extent of surgery are based upon a model that utilizes genotype- phenotype correlations to stratify mutations into three risk levels.

Jimenez C, Gagel RF. · Division of Internal Medicine, Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas M.D. Anderson Cancer Center, Box 433, 1515 Holcombe Blvd., Houston, TX, USA. · Growth Horm IGF Res. · Pubmed #15135800 No free full text.

Abstract: Multiple endocrine neoplasia type 2 (MEN2) is a syndrome characterized by medullary thyroid carcinoma (MTC), unilateral or bilateral pheochromocytoma and hyperparathyroidism. Familial MTC (FMTC) is a subvariant of MEN2 in which affected individuals develop MTC without other manifestations of MEN2. The identification of RET proto-oncogene mutations in MEN2 and FMTC have provided a precise method for identifying gene carriers. This review provides a concise discussion of the use of genetic testing in the management of hereditary MTC, discussing the appropriate use of this new technology with an emphasis on early intervention to prevent death or serious morbidity from this disease.

Fleming JB, Lee JE, Bouvet M, Schultz PN, Sherman SI, Sellin RV, Friend KE, Burgess MA, Cote GJ, Gagel RF, Evans DB. · Department of Surgical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston 77030, USA. · Ann Surg. · Pubmed #10561095 links to  free full text

Abstract: OBJECTIVE: To evaluate surgical complications, patterns of lymph node metastases, and calcitonin response to compartment-oriented lymphadenectomy in patients with primary or recurrent medullary thyroid carcinoma (MTC). SUMMARY BACKGROUND DATA: The majority of patients with invasive MTC have metastasis to regional lymph nodes at the time of diagnosis, as evidenced by the frequent finding of persistently elevated calcitonin levels after thyroidectomy and the high rates of recurrence in the cervical lymph nodes reported in retrospective studies. These data have provided the rationale for surgeons to perform a more extensive lymphadenectomy at the time of initial thyroidectomy and to consider reoperative cervical lymphadenectomy in patients with persistently elevated calcitonin levels after thyroidectomy. METHODS: Forty patients underwent surgery for MTC from 1991 to 1997 (23 sporadic cases, 17 familial cases). Patients were divided into three groups based on whether they had undergone previous thyroidectomy and on the results of standardized staging studies performed after referral to the authors' institution. Group 1 (11 patients) had received no previous surgery; group 2 (13) underwent thyroidectomy before referral and had an elevated calcitonin level without radiologic evidence of local regional or distant metastases; and group 3 (16) underwent thyroidectomy before referral and had an elevated calcitonin level with radiologic evidence of local-regional recurrence. The central neck compartment was dissected in all patients; preoperative staging and the extent of previous surgery dictated the need for lateral (modified radical) neck dissection. After primary or reoperative surgery, calcitonin levels were assessed. RESULTS: All patients had major reductions in postoperative calcitonin levels. Seven (29%) of 24 patients in groups 1 and 2 achieved normal calcitonin values compared with only 1 (6%) of 16 in group 3. Postoperative complications included seven cases (17%) of permanent hypoparathyroidism; five (71%) of these occurred in group 3. There were no iatrogenic recurrent laryngeal nerve injuries; one patient required recurrent nerve resection to achieve complete tumor extirpation. At a median follow up of 35 months, local recurrence was documented in 5 (13%) of 40 patients. CONCLUSIONS: Compartment-oriented lymphadenectomy performed early in the course of MTC is safe and may return calcitonin levels to normal in up to 25% of carefully selected patients. However, reoperation for bulky cervical disease (group 3) rarely results in normal calcitonin levels and is associated with a high incidence of permanent hypoparathyroidism.

Evans DB, Fleming JB, Lee JE, Cote G, Gagel RF. · Department of Surgical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston 77030, USA. · Semin Surg Oncol. · Pubmed #9890740 No free full text.

Abstract: Medullary thyroid carcinoma (MTC) is a unique disease in solid tumor oncology due to its ability to secrete calcitonin (iCT), a highly sensitive and specific serum marker of persistent or recurrent disease even at a microscopic level. The relatively long duration of survival experienced by most patients with MTC combined with the visible nature of surgical complications, when they occur, has caused most surgeons to take a conservative approach to the operative management and follow-up of patients with MTC. In contrast, the patient, family physician, and endocrinologist watch the iCT slowly rise, indicative of persistent and usually progressive invasive cancer. Amidst this clinical dilemma, we developed a standardized diagnostic and operative strategy to maximize local-regional tumor control and facilitate patient management.

Santarpia L, Gagel RF, Sherman SI, Sarlis NJ, Evans DB, Hoff AO. · Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA. · Head Neck. · Pubmed #18798312 No free full text.

Abstract: BACKGROUND: Medullary thyroid cancer (MTC) commonly metastasizes to lymph nodes in the central and lateral neck, but spread to distant organs also occurs, typically involving lung, liver, and bone. Metastases to pituitary gland are rare for this tumor. METHODS: We describe an unusual case and peculiar presentation of pituitary metastasis from MTC. We report clinical, genetic, and laboratory data of this patient. RESULTS: A young woman with multiple endocrine neoplasia type 2B was seen with recent onset of classic symptoms and signs of panhypopituitarism, mild diabetes insipidus, and optic chiasmatic compression. Transphenoidal resection of an intrapituitary mass confirmed the presence of metastatic MTC. CONCLUSIONS: MTC recurrence may present solely with subacute pituitary symptomatology, even in the context of a very lengthy interval after initial surgery, atypically low calcitonin plasma levels, carcinoembryonic antigen doubling times, and the concomitant absence of other tell-tale signs of disseminated metastatic disease.

Ye L, Santarpia L, Cote GJ, El-Naggar AK, Gagel RF. · Department of Endocrine Neoplasia and Hormonal Disorders, Unit 433, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030, USA. · J Clin Endocrinol Metab. · Pubmed #18765511 No free full text.

Abstract: CONTEXT: Activating mutations in the RET protooncogene have been demonstrated in multiple endocrine neoplasia 2 and sporadic medullary thyroid carcinoma (MTC). However, the complete genetic etiology underlying MTC tumorigenesis remains unclear. OBJECTIVE: Our objective was to define more precisely the chromosomal regions and uncover novel genes associated with MTC tumorigenesis. DESIGN AND SETTING: In this study, we used high resolution array-based comparative genomic hybridization to define tumor-associated copy number alterations (CNA) in 30 primary MTCs: 20 sporadic tumors (50% of which harbored RET mutation), and 10 hereditary. RESULTS: We identified 98 CNA, including 76 genomic allelic losses, two gains, and 20 copy number variations associated with MTC. Across sporadic and hereditary groups, there was a similar and overlapping pattern of predominant allelic loss. There were 29 regions containing at least 30% CNA in the 30 tumor samples. The most frequent allelic loss occurred in four loci, 7q36.1, 12p13.31, 13q12.11, and 19p13.3-11. No regions were found to be uniquely altered in the hereditary tumors. There were 21 CNA specific to sporadic MTC, with loss of 11q23.3 uniquely altered in RET negative tumors. Pathway analysis found cellular growth and proliferation as the most significant overall target, and cell death as the most significant pathway targeted in sporadic MTC. CONCLUSIONS: Our findings underscore the importance of candidate tumor suppressor genes together with RET alterations in MTCs. Despite of RET status, all MTC might share similar oncogenetic mechanisms. Dysfunction of cell proliferation and cell death may both be involved in MTC tumorigenesis.

Santarpia L, El-Naggar AK, Sherman SI, Hymes SR, Gagel RF, Shaw S, Sarlis NJ. · Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA. · Thyroid. · Pubmed #18651821 No free full text.

Abstract: Cutaneous metastasis from thyroid cancer, especially medullary thyroid cancer (MTC) is rare. We report four patients with cutaneous metastases from sporadic MTC, three women and one man, aged 50 to 69 years. They presented different cutaneous lesions phenotypes. The first patient had a remote history of MTC and initial presentation of the recurrence was a rapidly progressing cutaneous lesion; on subsequent disease staging, widely metastatic disease was discovered. The other three patients developed cutaneous metastases in the presence of known distant metastases, indicating systemic spread of thyroid cancer. Definitive diagnosis of cutaneous metastases of MTC was made on biopsy of the lesions with cells that stained positive for neuroendocrine markers. Accurate diagnosis of cutaneous metastasis from MTC is important because it is a negative prognostic factor indicative of multisystemic disease. Thus, MTC metastases should be included in the differential diagnosis of erythematous maculopapular eruptions and nodular lesions of the skin, especially when these metastases occur in the upper part of the body and if the patient has a history of MTC. The appearing of cutaneous metastasis is a negative prognostic factor since all the patients here described died within one year from the diagnosis of cutaneous metastases.

Grubbs EG, Rich TA, Li G, Sturgis EM, Younes MN, Myers JN, Edeiken-Monroe B, Fornage BD, Monroe DP, Staerkel GA, Williams MD, Waguespack SG, Hu MI, Cote G, Gagel RF, Cohen J, Weber RS, Anaya DA, Holsinger FC, Perrier ND, Clayman GL, Evans DB. · Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA. · Curr Probl Surg. · Pubmed #18346477 No free full text.

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Ghori F, Polder KD, Pinter-Brown LC, Hoff AO, Gagel RF, Sherman SI, Duvic M. · Department of Dermatology, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Box 434, Houston, Texas 77030, USA. · J Clin Endocrinol Metab. · Pubmed #16595600 links to  free full text

Abstract: CONTEXT: Denileukin diftitox is a recombinant novel fusion protein of diphtheria toxin and the ligand-binding domain of human IL-2. Denileukin diftitox binds to the high-affinity IL-2 receptor on the cell surface, and it is internalized by endocytosis and enzymatically cleaved. The cytotoxic A-fragment of the toxin inhibits protein synthesis and causes cell death. OBJECTIVE: The objective of this study was to recognize thyrotoxicosis in association with denileukin diftitox therapy. DESIGN: This study was a retrospective case series. SETTING: The setting of this study was a comprehensive cancer center. PATIENTS: Eight mycosis fungoides patients who were receiving 9 or 18 microg/kg.d iv denileukin diftitox for 5 d every 3 wk were identified with thyrotoxicosis. INTERVENTION(S): Thyroid testing was performed. Hypothyroidism after thyrotoxicosis was treated. RESULTS: In eight mycosis fungoides patients who developed transient thyrotoxicosis during therapy, thyroid function tests were normal before onset of therapy. Clinical thyrotoxicosis developed within days of the first cycle of denileukin diftitox therapy in four patients and after the second cycle in the other four patients. Symptoms included tremors, nervousness, tachycardia, diarrhea, and weight loss. After cessation of denileukin diftitox, thyrotoxicosis resolved in all patients; two became euthyroid, and five became hypothyroid, requiring levothyroxine therapy. One patient was lost to follow-up. CONCLUSIONS: Monitoring thyroid function before and during treatment with denileukin diftitox is recommended. Symptomatic thyrotoxicosis may be missed due to other acute reactions to the drug, and subsequent hypothyroidism may develop.

Schinke T, Liese S, Priemel M, Haberland M, Schilling AF, Catala-Lehnen P, Blicharski D, Rueger JM, Gagel RF, Emeson RB, Amling M. · Department of Trauma, Hand, and Reconstructive Surgery, Hamburg University School of Medicine, Martinistrasse 52, Hamburg 20246, Germany. · J Bone Miner Res. · Pubmed #15537449 No free full text.

Abstract: We recently described an unexpected high bone mass phenotype in mice lacking the Calca gene that encodes CT and alphaCGRP. Here we show that mice specifically lacking alphaCGRP expression display an osteopenia caused by a decreased bone formation. These results show that alphaCGRP is a physiological activator of bone formation and that the high bone mass phenotype of the Calca-deficient mice is caused by the absence of CT. INTRODUCTION: Calcitonin (CT) and alpha-calcitonin gene-related peptide (alphaCGRP) are two polypeptides without completely defined physiologic functions that are both derived from the Calca gene by alternative splicing. We have recently described an unexpected high bone mass phenotype in mice carrying a targeted deletion of the Calca gene. To uncover whether this phenotype is caused by the absence of CT or by the absence of alphaCGRP, we analyzed a mouse model, where the production of alphaCGRP is selectively abolished. MATERIALS AND METHODS: Bones from Calca(-/-) mice, alphaCGRP(-/-) mice, and their corresponding wildtype controls were analyzed using radiography, muCT imaging, and undecalcified histology. Cellular activities were assessed using dynamic histomorphometry and by measuring the urinary collagen degradation products. CT expression was determined using radioimmunoassay and RT-PCR. Immunohistochemistry was performed using an anti-CGRP antibody on decalcified bone sections. RESULTS: Unlike the Calca-deficient mice, the alphaCGRP-deficient mice do not display a high bone mass phenotype. In contrast, they develop an osteopenia that is caused by a reduced bone formation rate. Serum levels and thyroid expression of CT are not elevated in alphaCGRP-deficient mice. While CGRP expression is detectable in neuronal cell close to trabecular bone structures, the components of the CGRP receptor are expressed in differentiated osteoblast cultures. CONCLUSION: The discrepancy between the bone phenotypes of Calca(-/-) mice and alphaCGRP(-/-) mice show that the high bone mass phenotype of the Calca(-/-) mice is caused by the absence of CT. The osteopenia observed in the alphaCGRP(-/-) mice that have normal levels of CT further show that alphaCGRP is a physiologic activator of bone formation.

Jimenez C, Habra MA, Huang SC, El-Naggar A, Shapiro SE, Evans DB, Cote G, Gagel RF. · The University of Texas MD Anderson Cancer Center, Department of Endocrine Neoplasia and Hormonal Disorders, 1515 Holcombe Boulevard, Unit 435, Houston, Texas 77030, USA. · J Clin Endocrinol Metab. · Pubmed #15292360 links to  free full text

Abstract: Prior experience in kindreds with a codon 891 RET protooncogene mutation indicates that carriers of this mutation develop only hereditary medullary thyroid carcinoma without evidence of other manifestations of multiple endocrine neoplasia type 2. In this paper, we report the first documented case in which medullary thyroid carcinoma and pheochromocytoma were clinically expressed in members of a family affected by the codon 891 RET mutation. Genetic analysis of the RET protooncogene in this family revealed an exon 15 missense mutation at codon 891 that resulted in a serine to alanine amino acid substitution. These findings indicate that patients with this mutation should be screened for pheochromocytoma.

Jimenez C, Dang GT, Schultz PN, El-Naggar A, Shapiro S, Barnes EA, Evans DB, Vassilopoulou-Sellin R, Gagel RF, Cote GJ, Hoff AO. · Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 435, Houston, TX 77030, USA. · J Clin Endocrinol Metab. · Pubmed #15240641 links to  free full text

Abstract: Hereditary medullary thyroid carcinoma, a tumor that arises from the parafollicular cells of the thyroid gland, occurs in isolation (as in familial medullary thyroid carcinoma), in association with hyperparathyroidism and pheochromocytoma (as in multiple endocrine neoplasia type 2A), or in association with pheochromocytoma, marfanoid habitus, and mucosal neuromas (as in multiple endocrine neoplasia type 2B). These genetic syndromes are associated with germline-activating mutations of the RET protooncogene, a cell surface tyrosine kinase receptor, which is believed to modulate specific intracellular signaling pathways involved in the regulation of C cell proliferation and apoptosis. RET-activating mutations involve two important functional areas of the receptor: the cysteine-rich extracellular domain and the intracellular tyrosine kinase domain. Multiple endocrine neoplasia type 2A and familial medullary thyroid carcinoma are more commonly associated with mutations in the cysteine-rich extracellular domain, whereas multiple endocrine neoplasia type 2B is exclusively associated with mutations involving the second intracellular tyrosine kinase domain. Here, we describe a novel missense mutation of the RET protooncogene that substitutes arginine for proline at codon 912 of the intracellular tyrosine kinase domain in a family with medullary thyroid carcinoma.

Yen TW, Shapiro SE, Gagel RF, Sherman SI, Lee JE, Evans DB. · Department of Surgical Oncology, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA. · Surgery. · Pubmed #14668720 No free full text.

Abstract: BACKGROUND: The surgical management and follow-up strategy in patients with medullary thyroid carcinoma (MTC) remain controversial because of the lack of data on the natural history of these tumors and their patterns of progression. METHODS: We reviewed the records of all patients who underwent a cervical operation for MTC between 1991 and 2002. Compartment-oriented surgery (COS) was performed to minimize the risk of cervical recurrence. RESULTS: We identified 92 consecutive patients who underwent a cervical operation for MTC: 80 had invasive MTC, and 12 had C-cell hyperplasia after prophylactic thyroidectomy for familial MTC. Ten (13%) of the 80 patients with invasive MTC presented with distant metastases and underwent COS to achieve local-regional control; cervical recurrence developed in none, but three have died of MTC. The remaining 70 patients underwent COS for primary (n=23) or recurrent (n=47) MTC. Disease recurred in 18 (26%) of these 70 patients at a median follow-up of 35 months, with 10 (14%) of the recurrences being cervical. Recurrent disease was associated with a basal calcitonin level of >250 pg/mL in all but four patients, two of whom showed tumor dedifferentiation. In contrast, only 5 (11%) patients without evidence of recurrence had basal calcitonin levels of >250 pg/mL at last follow-up. CONCLUSIONS: Complete COS minimizes cervical recurrence. Radiographic evidence of recurrent disease is unlikely when the calcitonin level is < or =250 pg/mL. These data could be used to develop a logical, cost-effective treatment and follow-up strategy for patients with MTC.

Yip L, Cote GJ, Shapiro SE, Ayers GD, Herzog CE, Sellin RV, Sherman SI, Gagel RF, Lee JE, Evans DB. · Department of Surgical Oncology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA. · Arch Surg. · Pubmed #12686527 links to  free full text

Abstract: HYPOTHESIS: Multiple endocrine neoplasia type 2 (MEN 2) is caused by RET proto-oncogene mutations and has a strong penetrance for medullary thyroid carcinoma (MTC). Subtypes are defined by the presence or absence of pheochromocytomas, hyperparathyroidism, and characteristic clinical stigmas. We hypothesize that specific RET mutations correlate with the MEN 2 phenotype and aggressiveness of MTC. DESIGN: Review of endocrine surgery database from 1951 through 2002. SETTING: Tertiary referral center. PATIENTS: Eighty-six patients from 47 kindreds were identified with MEN 2A, MEN 2B, or familial MTC. Patients were classified into 3 RET mutation risk groups: level 1, low risk for MTC (codons 609, 768, 790, 791, 804, and 891); level 2, intermediate risk (codons 611, 618, 620, and 634); and level 3, highest risk (codons 883 and 918). MAIN OUTCOME MEASURES: Stage of MTC at diagnosis and at last follow-up and frequency of pheochromocytomas and hyperparathyroidism. RESULTS: RET analysis was complete for 71 patients from 39 kindreds. Multivariate analysis identified an increased likelihood of stage III or IV MTC at diagnosis with increasing age (odds ratio, 1.12 per year of age at thyroidectomy; 95% confidence interval, 1.07-1.17; P<.001) and increasing risk group (odds ratio, 14.23 per incremental increase in MTC risk group from 1 to 3; 95% confidence interval, 3.05-66.55; P<.001). Pheochromocytomas were found in 21 patients from 12 kindreds; 20 of 21 patients had codon 634 or 918 mutations. Hyperparathyroidism was found in 10 patients from 7 kindreds; 7 of 10 patients had codon 634 mutations. CONCLUSION: Specific RET mutations predict the phenotypic expression of disease and the MTC aggressiveness in patients with MEN 2, guiding the timing of thyroidectomy and screening for pheochromocytoma.

Huang SC, Torres-Cruz J, Pack SD, Koch CA, Vortmeyer AO, Mannan P, Lubensky IA, Gagel RF, Zhuang Z. · Molecular Pathogenesis Unit, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA. · J Clin Endocrinol Metab. · Pubmed #12519890 links to  free full text

Abstract: We have previously identified two second hit mechanisms involved in the development of multiple endocrine neoplasia type 2 (MEN 2)-associated tumors: trisomy 10 with duplication of the mutant RET allele and loss of the wild-type RET allele. However, some of the MEN 2-associated tumors investigated did not demonstrate either mechanism. Here, we studied the TT cell line derived from MEN 2-associated medullary thyroid carcinoma with a RET germline mutation in codon 634, for alternative mechanisms of tumorigenesis. Although we observed a 2:1 ratio between mutant and wild-type RET at the genomic DNA level in this cell line, fluorescence in situ hybridization analysis revealed neither trisomy 10 nor loss of the normal chromosome 10. Instead, a tandem duplication event was responsible for amplification of mutant RET. In further studies we could for the first time demonstrate that the genomic chromosome 10 abnormalities in this cell line cause an increased production of mutant RET mRNA. These findings provide evidence for a third second hit mechanism resulting in overrepresentation and overexpression of mutant RET in MEN 2-associated tumors.

Koch CA, Huang SC, Moley JF, Azumi N, Chrousos GP, Gagel RF, Zhuang Z, Pacak K, Vortmeyer AO. · Pediatric and Reproductive Endocrinology Branch, National Institute of Child Health and Human Disease (NICHD), National Institutes of Health, Bethesda, Maryland 20892, USA. · Oncogene. · Pubmed #11753660 links to  free full text

Abstract: Germline mutations of the RET proto-oncogene are responsible for the familial tumor syndrome called multiple endocrine neoplasia type 2 (MEN 2) that includes medullary thyroid carcinoma (MTC). Although inherited mutations of RET lead to tumor formation in patients with MEN 2, it is not understood why only selected cells develop into tumors. We have recently shown that duplication of the mutated RET allele or loss of the wild-type allele might represent mechanisms of tumorigenesis in patients with MEN 2A-related pheochromocytoma. We now analysed 19 DNA samples of MTC (15 of which were non-microdissected, four of which were microdissected) from patients with MEN 2A. Using polymorphic marker and phosphorimage densitometry analyses, we found allelic imbalance of the mutated and wild-type RET allele in six of 19 DNA MTC samples. Of note, two of the four microdissected tumor DNA samples showed allelic imbalance of RET, whereas only four of the 15 non-microdissected MTC samples did. These results underscore the significance of microdissection in the analysis of tumor DNA. In our study, some of the non-microdissected tumor DNA samples may have failed to display allelic imbalance of RET, because of contamination of tumor DNA with nonneoplastic DNA or noninformative microsatellite marker analysis. Taken together, our results suggest allelic imbalance between mutated and wild-type RET as a possible mechanism for tumor formation in some patients with MEN 2A-related MTC.

Wohllk N, Becker P, Youlton R, Cote GJ, Gagel RF. · Sección de Endocrinología, Departamento de Medicina, Hospital del Salvador, Laboratorio IEMA, Santiago de Chile. · Rev Med Chil. · Pubmed #11552438 No free full text.

Abstract: BACKGROUND: Medullary thyroid carcinoma (MTC) may occur either as a sporadic or familial disease. Multiple endocrine neoplasia (MEN) type 2, inherited as an autosomal dominant disease, is characterized by MTC only (FMTC) or coexistence of MTC with other endocrine neoplasia (NEM 2A, 2B). Germline mutations of the RET proto-oncogene (cRet) are found in the inherited forms and in some apparently sporadic MTC cases. AIM: To study RET mutations in 8 families with MEN 2. MATERIAL AND METHODS: RET mutations were screened in peripheral blood DNA from 18 patients and 87 high risk carriers belonging to 8 MEN 2 families and 52 sporadic MTC. Exons 10, 11, 13, 14, 15 and 16 of the c-Ret were amplified by polymerase chain reaction (PCR) and examined by direct sequencing of PCR products and/or restriction enzyme analysis. RESULTS: Five MEN 2A and one FMTC families with a germline mutation at codon 634, one MEN 2A and one FMTC family carrying a mutation at codon 620 were identified. Mutations were found in 23 out of 87 high risk carriers. In addition, we detected a S891A (exon 15) germline mutation in a sporadic MTC patient and in one out of her three sons and V804M (exon 14) in another sporadic MTC case and in one out of his six relatives, indicating in both cases the presence of a sporadic misclassified familial disease. CONCLUSIONS: These results underscore the importance of routine application of c-Ret testing in all cases of MTC either familial or sporadic.

Parthasarathy R, Cote GJ, Gagel RF. · Department of Internal Medicine Specialties, The University of Texas M.D. Anderson Cancer Center, Houston 77030, USA. · Cancer Res. · Pubmed #10463581 links to  free full text

Abstract: Activating mutations of the RET proto-oncogene cause hereditary medullary thyroid carcinoma. To examine whether selective inactivation of mutant RET could prevent transformation, a hammerhead ribozyme was designed to cleave RET mRNA containing a transforming mutation of codon 634 TGC --> TAC (Cys634Tyr). In vitro RNA cleavage assay demonstrated that the ribozyme selectively cleaved RET RNA with a Cys634Tyr but not Cys634Arg or the normal sequence. Expression of ribozyme in NIH/3T3 cells prevented RET-mediated colony formation in soft agar. This inhibition required catalytically active ribozyme and was specific for the TAC mutation. Therefore, ribozymes designed to selectively target mutant RET RNA may provide an effective therapeutic in the treatment of this syndrome.

Dang GT, Cote GJ, Schultz PN, Khorana S, Decker RA, Gagel RF. · The University of Texas, MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX, 77030, USA. · Mol Cell Probes. · Pubmed #10024437 No free full text.

Abstract: A ser891ala RET proto-oncogene mutation has been previously discovered in a single kindred with familial medullary thyroid carcinoma (FMTC). An additional two probands with this mutation and with medullary thyroid carcinoma (MTC) without any other manifestations of MEN 2 have been identified. In one of thse families, two other individuals also had the mutant sequence and FMTC. Analysis of both cases showed cosegregation of the mutation and MTC. To facilitate detection of this mutation, a primer was engineered which creates a Hha I recognition site in the presence of the mutant sequence. As a result, this codon 891 exon 15 mutation can be identified with a restriction enzyme digestion.

Grubbs EG, Rich TA, Li G, Sturgis EM, Younes MN, Myers JN, Edeiken-Monroe B, Fornage BD, Monroe DP, Staerkel GA, Williams MD, Waguespack SG, Hu MI, Cote G, Gagel RF, Cohen J, Weber RS, Anaya DA, Holsinger FC, Perrier ND, Clayman GL, Evans DB. · No affiliation provided · Curr Probl Surg. · Pubmed #18346476 No free full text.

This publication has no abstract.