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PubMed2001

Nuclear factor-kappaB is constitutively active in C-cell carcinoma and required for RET-induced transformation.

Specific point mutations of the RET proto-oncogene have been demonstrated to be responsible for multiple endocrine neoplasia (MEN) types 2A and 2B, for familial medullary thyroid carcinoma (MTC) syndromes, as well as for sporadic MTC. Here we show that nuclear factor (NF)-kappaB is activated in RET-associated C-cell carcinoma specimens. TT cells, a human MTC cell line expressing MEN 2A type RET, display transcriptionally active RelA(p65) in the nucleus. NF-kappaB activity in these cells is attributable to constitutive IkappaB kinase (IKK) activity and high turn over of IkappaBalpha. RET harboring the mutations C634R (MEN 2A) or M918T (MEN 2B), in contrast to wild-type RET, activates a NF-kappaB-dependent reporter construct upon transient transfection in HeLa cells. We show that the prototype RET mutation C634R enhances phosphorylation of IkappaBalpha by IKKbeta but not by IKKalpha. RET-induced NF-kappaB and IKKbeta activity requires Ras function but does neither involve the classical mitogen-activated protein kinase kinase/extracellular signal-regulated kinase nor the phosphoinositide 3-kinase/Akt pathways. In contrast, RET-induced NF-kappaB activity is dependent on Raf and MEKK1. Inhibition of constitutive NF-kappaB activity results in cell death of TT cells and blocks focus formation induced by oncogenic forms of RET in NIH 3T3 cells. These results suggest that RET-mediated carcinogenesis critically depends on IKK activity and subsequent NF-kappaB activation.

3T3 Cells↗

PubMed2000

[Medullary carcinoma of the thyroid gland].

We report the experience of the Institute of Surgical Pathology of the University of Parma on three patients with sporadic medullary thyroid carcinoma (MTC). MTC is a tumor of parafollicolor cells origin (C cells). The surgical excision of the thyroid tumor and cervical node metastases is potentially curative. The other therapeutic options are limited. Considerable emphasis has been placed on early diagnosis and surgery for multiple endocrine neoplasia (MEN) related MTC. Genetic screening promises earlier and accurate diagnosis (RET gene mutations are found in MEN).

Adult↗

PubMed2001

Serum cytokeratins determination in differentiated thyroid carcinoma.

To assess the potential value of cytokeratins (CK) 8,18,19 as tumor markers for thyroid diseases, a study was performed comparing serum CK 8,18,19 levels in patients affected from thyroid carcinoma, adenoma, other benign thyroid diseases and healthy volunteers as controls. One hundred cases (65 patients and 35 controls) were examined. Thirty patients had thyroid carcinoma (18 papillary--PTC, 8 follicular--FTC, 4 medullary--MTC), 19 non-toxic goiter, 10 thyroid adenoma, 6 chronic thyroiditis and 35 healthy volunteers as controls. These controls were matched by age and sex. The mean value of CK in benign thyroid diseases (46.1 U/L) was significantly higher (p<0.02) than that in healthy controls (29.6 U/L). The mean value of CK in carcinomas (68.1 U/L) was significantly higher than that in healthy controls (p<0.01) and benign thyroid diseases patients (p<0.05). The positive rate of CK in thyroid carcinomas was 28.1%, while in benign thyroid diseases was 17.8%. The CK sensitivity for thyroid carcinomas was 28.1%, with a specificity of 80% and accuracy of 70.4%. In PTC patients the mean CK value was not significantly higher than in the benign diseases' group and in healthy subjects. No evident correlation between CK levels and tumor mass was found. In FTC patients the mean value was significantly higher than in the benign diseases' group and in healthy subjects. Large tumors showed the highest levels, while small tumor values were similar to the control ones. In MTC patients the mean value was significantly higher than in the benign diseases' group and in healthy subjects, with the highest peaks in large tumors and metastatic tumors. The detection of increased values in thyroid carcinomas with high metastatic potential (FTC and MTC) seems to confirm the role of these antigens in predicting the malignancy's degree of the neoplasm. These findings, if confirmed in larger series, could play an important role in assessing the CK 8,18,19 serum level as a real prognostic factor. Further repeated serum determinations after total thyroidectomy might indicate the role of CK 8,18,19 as serum markers predicting the risk of metastases.

Adenocarcinoma, Follicular↗

PubMedDate not supplied

Persistent hypercalcitoninemia in patients with medullary thyroid cancer: a therapeutic approach based on selective venous sampling for calcitonin.

BACKGROUND: Persistent or recurrent medullary thyroid carcinoma (MTC) can be cured by microdissection of residual metastatic lymph nodes in the neck. Selective venous sampling can be used for localization. The aim of this study is to prospectively analyze our results with a therapeutic approach based on venous sampling, in patients with hyperthyrocalcitoninemia after thyroidectomy for MTC. METHODS: Selective venous sampling for determination of stimulated calcitonin was obtained in all patients after performing a complete laboratory and imaging workup. Patients with a gradient between the suprahepatic vein and the superior vena cava underwent unilateral or bilateral extensive lymph node dissection. We used the gradient between the right and left jugular veins to decide which side of the neck to operate. Calcitonin levels were obtained after surgery and a pentagastrin test was performed one year later if basal levels remained normal. RESULTS: Mean age of the five women with a neck gradient in the selective venous sampling who underwent neck exploration was 45 years. In all patients metastatic lymph nodes were found at the site suggested by the study. Mean positive/resected lymph nodes were 5/20. Postoperative basal and stimulated levels of calcitonin became normal in two patients at one year of follow up. CONCLUSION: Selective venous sampling is useful to localize recurrent MTC.

Adult↗

PubMed2001

[A case of enucleation for multiple renal cell carcinomas in unilateral kidney with microwave tissue coagulator].

A 67-year-old man, who had undergone left nephroureterectomy for ureteral tumor (transitional cell carcinoma, G1) eight years previously, was found to have two renal tumors in the residual right kidney by the follow-up computed tomography (CT). We performed non-ischemic enucleation for multiple tumors at the upper and lower pole in the unilateral kidney using a microwave tissue coagulator (MTC). We confirmed by means of ultrasonography during operation the absence of any other satellite tumors. The operation time was 154 minutes and bleeding during operation was 267 ml. There was no difference between creatinine before (0.73 mg/dl) and after (0.79 mg/dl) operation. On the follow-up CT, there was a low density area after enucleation. This area gradually decreased and disappeared on enhanced CT 18 months after operation. We enucleated multiple renal cell carcinomas using MTC without reduction of renal function or remarkable side effects. These results suggested that non-ischemic enucleation using MTC would be useful for multiple renal cell carcinoma in the unilateral kidney.

Aged↗

PubMed2001

[Mycobacterium tuberculosis detection by polymerase chain reaction and identification of M. tuberculosis strain].

A rapid multiprimer PCR method for detection of Mycobacterium tuberculosis complex (MTC) and simultaneous identification of M. tuberculosis in clinical samples has been developed. The method is based on simultaneous amplification of two targets: a 401 bp region from the mtp40 species-specific gene sequence of M. tuberculosis and a 544 bp fragment from the RD1 genome region which is specific for MTC but absent in BCG strains. Polymerase inhibitors in this study were detected by internal control in each test. Detection sensitivity was 25 copies of M. tuberculosis genomic DNA. Seven methods for isolation of mycobacterial DNA were compared and the technique with chloroform extraction was selected as the most efficient. The proposed method was used for analysis of 37 clinical samples and the results were compared with the results of culturing, acid-fast bacilli staining, and clinical diagnosis. The method proved to be sufficiently sensitive and specific for detection of mycobacterial DNA. Moreover, in countries with only two main pathogenic species of MTC circulating (M. tuberculosis and M. bovis) this method can be used for differentiation of these two species.

DNA, Bacterial↗

PubMed2001

Novel technique for scanning of codon 634 of the RET protooncogene with fluorescence resonance energy transfer and real-time PCR in patients with medullary thyroid carcinoma.

BACKGROUND: The multiple endocrine neoplasia 2 (MEN 2) syndromes [MEN 2A, MEN 2B, and familial medullary thyroid carcinoma (FMTC)] are caused by germline mutations of the RET protooncogene. Because 85% of MEN 2A patients and 30% of FMTC patients have mutations at codon 634, the recommended molecular analyses begin at exon 11, where codon 634 is located. METHODS: We scanned codon 634 of the RET protooncogene with real-time PCR and fluorescence resonance energy transfer (FRET), using a unique pair of internal probes to detect mutations localized at codon 634. We compared results with sequencing results in 66 patients. RESULTS: The method detected all codon 634 mutations available in our laboratory (Cys634Tyr, Cys634Arg, Cys634Phe, Cys634Trp). Comparing this method with the direct sequencing of exon 11 in a cohort of 66 patients with MTC, the system identified all 14 MTC patients carrying germline mutations at codon 634. One apparent false-positive result occurred among 52 patients. CONCLUSIONS: The simultaneous scanning of multiple mutations is possible with the FRET system. The method allows rapid characterization of germline mutations at codon 634 in MTC patients.

Carcinoma, Medullary↗

PubMed2002

18F-FDG PET detection of lymph node metastases in medullary thyroid carcinoma.

UNLABELLED: Postsurgically elevated or increasing serum calcitonin levels strongly suggest the presence of residual or recurrent medullary thyroid carcinoma (MTC). Several imaging modalities (sonography, MRI, CT, scintigraphy with different types of radiolabeled ligands, etc.) are routinely used in an attempt to localize tumorous tissue, but such efforts often fail. In the search for a more reliable method, 18F-FDG PET was applied to detect tumor tissue of residual or recurrent MTC. METHODS: Forty patients with a postoperatively elevated plasma calcitonin level were included. These patients underwent routine diagnostic imaging procedures (CT, MRI, and 131I-metaiodobenzylguanidine [MIBG] whole-body planar scintigraphy or SPECT) and 18F-FDG PET examinations. Two independent experts visually analyzed the images provided by each method to detect pathologic lesions. Lymph nodes of > or = 1 cm in short diameter that were detected by radiologic methods were considered to be pathologic. 18F-FDG accumulation with a sharp contour reported by both independent observers was similarly regarded as pathologic. RESULTS: PET detected 270 foci with a high tracer accumulation, whereas only 116 lesions were detected by MRI and 141 by CT. The numbers of such foci determined by PET, MRI, and CT were 98, 34, and 34, respectively, in the neck; 25, 5, and 6, respectively, in the supraclavicular regions; and 117, 35, and 39, respectively, in the mediastinum. 131I-MIBG scintigraphy findings were positive for only 3 patients. CONCLUSION: For MTC patients with a postoperatively elevated plasma tumor marker level, PET was more sensitive and superior in localizing tumorous lymph node involvement than were the other imaging modalities, especially in the cervical, supraclavicular, and mediastinal lymphatic regions.

Biomarkers, Tumor↗

PubMed2001

The genetic background of medullary thyroid carcinoma in young patients.

The study was undertaken to evaluate the frequency of RET polymorphisms at codons 769 and 836 in young medullary thyroid carcinoma (MTC) patients in whom the presence of a known germline mutation has been excluded. 40 patients aged 10-29 were subjected to genetic analysis of RET exons 10, 11, 13, 14 and 16 and compared to 140 older patients. The hereditary component occurred to be very high in young MTC patients: 57% carry the germline mutation, other 28% exhibit at least one rare polymorphic variant of RET. The observed allelic frequencies were 38% for polymorphic variant L769CTG and 6% for variant S836AGT. The results were significantly higher than those obtained in the group of older patients: 20% and 1% for L769CTG and S836AGT, respectively. Our results speak in favour that the polymorphism in RET codon 769 and 836 may also be a factor predisposing to the development of MTC in young age.

Adult↗

PubMed2002

[FDG PET scan of metastases in recurrent medullary carcinoma of the thyroid gland].

Searching for metastases of medullary thyroid cancer (MTC), FDG PET was applied. PET results were compared with those of conventional diagnostic imaging procedures. After primary treatment, 52 MTC patients with elevated serum tumor marker levels and/or general symptoms (diarrhoea/flush) underwent radiological (CT/MRI), 131-iodine labeled metaiodo-benzylguanidine (MIBG) whole-body scintigraphy and FDG PET investigations. At least one pathological lesion was detected in 49 patients by PET, 35 by CT, 32 by MRI and 3 by MIBG. FDG PET was far superior to the other methods in identifying metastases in the supradiaphragmatic lymphatic regions. In the follow-up of MTC patients, FDG PET was more sensitive in localizing tumorous LN involvement, especially in the cervical, supraclavicular and mediastinal lymphatic regions, compared to other imaging modalities.

Adult↗

PubMed2002

Frequent epigenetic silencing of the CpG island promoter of RASSF1A in thyroid carcinoma.

Loss of heterozygosity of chromosome 3p21 is one of the most frequent alterations in solid tumors, including thyroid carcinomas. Recently, we have characterized the novel tumor suppressor gene RASSF1 located in this locus. The RASSF1A isoform is epigenetically inactivated in a variety of human primary tumors. In this study, we investigated the expression and methylation status of the RASSF1 gene in thyroid carcinoma. In nine thyroid cancer cell lines, the RASSF1A promoter CpG island was methylated completely, and expression was absent. Treatment of these cell lines with the DNA methylation inhibitor 5-aza-2'-deoxycytidine reactivated the transcription of RASSF1A. The methylation status of the RASSF1A promoter was analyzed in 38 primary thyroid tumors, including 1 poorly differentiated thyroid carcinoma, 5 medullary thyroid carcinoma (MTC), 10 follicular thyroid carcinoma (FTC), 9 undifferentiated thyroid carcinoma (UTC), and 13 papillary thyroid carcinoma (PTC). In 71% of thyroid carcinomas, the RASSF1A CpG island was hypermethylated. Methylation frequency was higher in the aggressive forms of thyroid carcinoma and was found in 80% of MTC, in 78% of UTC, and in 70% of FTC, compared with 62% in the more benign PTC. RASSF1A inactivation was detected in all stages of thyroid carcinoma scored by Tumor-Node-Metastasis classification. Additionally, we analyzed the methylation frequency of the CpG island of cell cycle inhibitor p16(INK4a) in the same thyroid tumors. The p16 gene was inactivated in 56 and 25% of cell lines and primary tumors, respectively. p16 methylation was detected in 56% of UTC, 10% of FTC, and 25% of PTC but not in MTC. In UTC, which belongs to the most aggressive carcinomas in humans, the most common combined inactivation of RASSF1A and p16 was detected. In general, 90% of tumors with p16 inactivation were also silenced for RASSF1A expression. However, RASSF1A hypermethylation was detected three times more frequently in thyroid cancers. Thus, RASSF1A inactivation may play a crucial role in the malignancy of thyroid carcinoma.

Carcinoma↗

PubMed2002

[Polyadenomatoses: type 2 multiple endocrine neoplasms].

FROM A CLINICAL POINT OF VIEW: Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant, inherited multiglandular disease with familial and individual age-related penetration and variable expression. A medullary thyroid carcinoma (MTC) is always concomitant to MEN2 and associated in varying proportion with pheochromocytoma (50%) and hyperparathyroidism (5 to 20%). PROGNOSTIC DATA: The prognosis of MEN2 is related to the carcinological evolution of MTC, which depends mainly on the stage of discovery and the quality of the first surgical treatment, emphasizing the need for early diagnosis. THE IMPORTANCE OF THE ERT GENE: The identification of mutations in proto-oncogene RET, responsible for the various forms of the disease allows subjects at risk in a family circle to be identified and early screening of various endocrine damage, notably MTC, should be performed. Biological explorations in all persons carrying this mutation would permit diagnosis and surgical treatment of the endocrine lesions, before their clinical manifestation.

Adrenal Gland Neoplasms↗

PubMedDate not supplied

Vancouver AIDS conference: special report. Three African countries to take part in trials to reduce mother-to-child transmission.

UNAIDS has announced that 1900 HIV-positive women in five sites in South Africa, Tanzania, and Uganda are to take part in a clinical trial to evaluate the efficacy and tolerance of three regimens for the prevention of mother-to-child (MTC) transmission of HIV in a population where breast-feeding is the norm. The regimens will use zidovudine in combination with 3TC, compared to a placebo. Some 3 million children are estimated to have been infected via MTC since the HIV epidemic started, and of these, 85% are in sub-Saharan Africa. HIV/AIDS prevalence among children in developing countries is about 35 times higher than in the industrialized world. A trial conducted in the US and France using zidovudine showed a 67% reduction in the risk of MTC transmission. But UNAIDS warns that the cost of this treatment, at about $1500 per mother-child pair, makes it impractical for widespread use in developing countries, where mothers tend to wait more than 30 weeks after birth for their first visit to a clinic, too late for the treatment to start. Breast feeding is another issue. For many mothers, the risk of their infant dying if not breast fed is greater than the risk of transmitting HIV by breast feeding. So the trial will try to ensure that any gains from early drug treatment are not simply lost again through losses due to breast feeding.

Adolescent↗

PubMed2002

Enhanced antitumor activity of combined pretargeted radioimmunotherapy and paclitaxel in medullary thyroid cancer xenograft.

A significant antitumor effect associated with moderate toxicity was obtained previously with anticarcinoembryonic antigen x antidiethylene-triaminepentaacetic acid (DTPA)-indium F6-734 bispecific antibody and iodine-131-labeled DTPA-indium bivalent hapten in an animal model of medullary thyroid cancer (MTC). The purpose of this study was to determine whether the cytotoxic agents doxorubicin and paclitaxel, also known as radiosensitizers, improve efficacy of pretargeted radioimmunotherapy (RIT) in experimental MTC. Nude mice bearing TT MTC xenograft were treated with F6-734 and iodine-131-labeled DTPA-indium bivalent hapten injected 48 h apart with or without doxorubicin or paclitaxel. The maximum tolerated dose (MTD) of RIT was 92.5 MBq (as determined previously) and that of doxorubicin and paclitaxel 200 and 1000 micrograms, respectively. A control group received no treatment. Animal weight, hematotoxicity, tumor volume, and serum calcitonin were monitored for 5 months. Tumor growth inhibition induced by drugs alone, RIT alone, or combined therapy was characterized by measuring relative tumor volume 20, 40, and 60 days after treatment to detect additivity or synergism. Mean tumor volume doubling time (MTVDT) was 13 +/- 4 days in the control group, 15 +/- 8 days in the group treated with the MTD of doxorubicin, and 32 +/- 13 days in the group treated with the MTD of paclitaxel. After RIT alone at 92.5 MBq, MTVDT was 86 +/- 22 days. After RIT at 74 MBq (80% of MTD), MTVDT was 56 +/- 10 days. MTVDT was not significantly different from this value after RIT plus doxorubicin, 60 +/- 16 days (65 and 100% of the respective single-agent MTDs). Combination of RIT with paclitaxel (65 and 100% of the respective single-agent MTDs) prolonged the suppression of tumor growth. One complete response was observed, and MTVDT was 114 +/- 44 days. This value was significantly longer than the value obtained with RIT alone at 74 MBq (P < 0.05) or with RIT combined with doxorubicin (P < 0.02). The change in serum calcitonin levels paralleled those in tumor volume. Analysis of dose-response curves at days 20 and 40 showed additivity between RIT and paclitaxel, and analysis at day 60 suggested a synergistic effect. In conclusion, addition of doxorubicin did not improve RIT efficacy, whereas paclitaxel improved RIT efficacy significantly without increasing toxicity.

Animals↗

PubMed1976

Adrenal medullary hyperplasia. A morphometric analysis in patients with familial medullary thyroid carcinoma.

The syndrome of familial medullary thyroid carcinoma (MTC), pheochromocytoma, and parathyroid hyperplasia is inherited as an autosomal dominant trait, and is characterized by development of bilateral and multicentric thyroidal and adrenal medullary tumors. One of the earliest manifestations of adrenal medullary hyperfunction in patients with this syndrome is an increased ratio of epinephrine to norepinephrine in urine. In order to define the morphologic correlates of these early catecholamine abnormalities in a large kindred with familial MTC, a morphometric analysis based on a point-counting system to asses adrenal medullary volume was undertaken. These studies clearly revealed adrenal medullary hyperplasia as reflected by a two- to three-fold increase in medullary volume and weight as compared to age- and sex-matched controls. The increase in total medullary mass resulted from diffuse and multifocal modular proliferations of adrenal medullary cells primarily within the head and body regions of the glands. These results support the hypothesis that the pheochromocytomas in patients with familial MTC may, in fact, represent extreme degrees of nodular hyperplasia of the medulla.

Adrenal Medulla↗

PubMed1992

Evaluation of children with medullary thyroid carcinoma.

Early diagnosis and surgical treatment of medullary thyroid carcinoma (MTC) in children is essential to decrease the likelihood of metastatic spread. From 1981 to 1991, eight children under 18 years of age (five girls and three boys) with MTC were seen and seven underwent total thyroidectomy. Follow-up ranged from 14 months to 10 years after surgery. Four of the seven presented with a neck mass and elevated basal levels of calcitonin (CT). After surgery, three had recurrent disease. In the other three, the diagnosis was made after several years of screening (normal basal values of CT but increased CT levels after calcium/pentagastrin infusion). All had normal stimulated CT values postoperatively. This follow-up showed that the prognosis for MTC in children depends predominantly upon its extent at the time of the diagnosis and treatment.

Adolescent↗

PubMed1992

[Current aspects of the pathology, diagnosis and therapy of C-cell carcinoma. A symposium held in Bonn, July 1991].

An essential element in the histological differentiation of medullary thyroid cancer (MTC) from other thyroid tumors is the use of immunohistochemical methods. The detection of calcitonin in the tumor cells is decisive. Factors which impair the prognosis of MTC are age (> 40 y), male sex, elevated DNA-content and mitotic activity of the tumor cells, immunoreactivity against dopa decarboxylase, histaminase and Leu-M1-antigen. Family screening is based mainly on calcitonin-stimulation tests (using pentagastrin or calcium) as a genetic marker for routine screening is not available yet. Scintigraphic methods using 99mTc-(V)-DMSA, 201Tl-chloride or 99mTc-anti-CEA antibodies become more important, especially in the detection of recurrent disease. Selective venous blood sampling is another sensitive method for localizing recurrent disease. Surgical treatment plays the dominant role in the management of MTC. Complete thyroidectomy in conjunction with systematic lymphadenectomy is now the primary treatment of choice.

Carcinoma↗

PubMed1992

Proto-oncogene analysis in multiple myeloma.

The genetic basis for the development of multiple myeloma (MM) remains poorly understood, in part because MM has thus far been relatively refractory to cytogenetic analysis. The few cases karyotyped have pointed to involvement of 11q13, site of the BCL1 proto-oncogene, or of 8q24, site of the MYC proto-oncogene. A recent molecular study detected rearrangements distal to the MYC gene in 16% of MM, using the MLVI-4 probe. The immunocytochemical demonstration of BCL2 protein overexpression in at least some cases of MM has suggested the possibility of translocation-mediated deregulation of the BCL2 proto-oncogene. The configuration of the BCL2 gene in MM, however, has not yet been defined using all available breakpoint probes. To address these issues, we studied 17 patients with plasma cell dyscrasias (16 MM, 1 plasmacytoma) by Southern blotting using the major breakpoint region (MBR), minor cluster region (MCR), and 5' cDNA (pB16) BCL2 breakpoint probes; with the BCL1 major translocation cluster (MTC) breakpoint probe; and with a probe to the MYC-associated MLVI-4 region (PA1.3SB). In all 17 cases, rearrangement of one or both alleles of the immunoglobulin heavy chain gene had been demonstrated, thereby confirming the presence of tumor DNA in the samples studied. None of the cases tested showed a rearrangement with the MBR BCL2 (0/16), MCR BCL2 (0/17), 5' cDNA BCL2 (0/16), BCL1 MTC (0/15), or MLVI-4 (0/15) probes. These results suggest that if BCL2 deregulation does indeed occur in MM, a mechanism other than translocation must be involved in most cases. Furthermore, rearrangements distal to the MYC gene, in the region of the MLVI-4 probe, may be less common than previously thought. Finally, a significant proportion of translocation breakpoints in band 11q13 may not be detected by the BCL1 MTC probe in MM, as is true in lymphomas.

Aged↗