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R Elisei

Publications and source records attributed to R Elisei.

At least 37 records · Page 2Linked to original sources
PubMed2000

RET proto-oncogene mutations in thyroid carcinomas: clinical relevance.

Different forms of RET mutations are found in papillary and medullary thyroid carcinomas. Rearrangements with other genes (RET/PTC oncogene) play a causative role in a significant proportion of papillary thyroid carcinomas. In this case, several factors influence the frequency and the type of RET/PTC, such as exposure to radiation, age and histological variant of the papillary tumor. On the other hand, the presence of the mutation does not seem to influence the biological behavior of the tumor or its response to conventional treatment modalities. In the setting of medullary thyroid cancer, germline RET point-mutations are implicated in the pathogenesis of virtually all hereditary forms and somatic point-mutations in nearly half of the sporadic forms. The clinical impact of this finding is that family members at-risk of hereditary MTC may be screened by genetic analysis, to distinguish those carrying or not-carrying the mutation. The last can be reassured on their status and relieved from further follow-up. Those with the mutation may be treated at a pre-clinical stage of the disease or even before the disease is started. The present review is focused on the clinical implication of RET gene mutations in thyroid cancer patients.

Carcinoma, Medullary↗
PubMed2000

New breakpoints in both the H4 and RET genes create a variant of PTC-1 in a post-Chernobyl papillary thyroid carcinoma.

Two main types of RET/PTC oncogene, named RET/PTC-1 and 3, occur in papillary thyroid carcinomas especially in those from Belarus children after the Chernobyl nuclear accident. Several variants of RET/PTC-3 have also been found, having different break points with respect to the classical RET/PTC-3. To our knowledge, no variant of RET/PTC-1 has been described up to now. We found a post-Chernobyl papillary thyroid carcinoma with an RET/PTC-1 rearrangement characterized by a transcript longer than expected. Sequence analysis of the PCR product obtained after RT-PCR revealed new fusion points between H4 and RET genes. The genomic sequence showed new breakpoints in both H4 intronic and in RET exonic regions. The RET gene breakpoint occurred within exon 11, at variance with the classical form of RET/PTC-1, in which it is in intron 11. As a consequence of this new fusion point, the transcript included 132 nucleotides of exon 11, coding for 44 amino acids of RET protein. Regarding the H4 gene, the classical breakpoint is in the first intron and the cDNA contains a fragment of 339 nucleotides. In our case the cDNA had a longer fragment of H4 involving a total of 1266 nucleotides. Sequencing of genomic DNA revealed a rearrangement breakpoint at position 886 of a new H4 intron located downstream of the 1266 coding region. Furthermore, as a consequence of the activation of a cryptic splicing site, 132 nucleotides of this intron were spliced between the H4 and RET genes. Sequence analysis of the new chimera showed that the original frames of H4 and RET were joint with the intronic sequence without disruption of the open reading frame (ORF). Moreover, the genomic DNA of this case showed transforming activity in the DNA-mediated transfection assay using NIH-3T3 cells. In conclusion, we describe here the first variant of RET/PTC-1 oncogene, which we have termed 'long'-PTC-1, characterized by new breakpoints of both genes involved in the rearrangement and having transforming activity. Similar to previously reported PTC-3 variants, long-PTC-1 has been found in a post-Chernobyl papillary thyroid carcinoma confirming that RET/PTC rearrangements other than the classical forms (RET/PTC-1 and -3) are specifically associated with radiation-induced papillary thyroid cancer.

Carcinoma, Papillary↗
PubMed2000

N-ras mutation in poorly differentiated thyroid carcinomas: correlation with bone metastases and inverse correlation to thyroglobulin expression.

Codon 61 of the N-ras oncogene was screened for mutations in 99 surgically resected thyroid carcinomas by a polymerase chain resection (PCR)-based method (PCR-primer introduced restriction with enrichment of mutant alleles [PCR-PIREMA]). A point mutation of the N-ras oncogene at the codon 61 was detected in 16 of 99 (16.2%) thyroid carcinomas examined by this method. No RAS alteration was detected in the group of 11 medullary thyroid carcinomas, while 3 of 31 (10.0%) papillary carcinomas, 2 of 5 (40%) follicular carcinomas, 8 of 44 (18.2%) poorly differentiated carcinomas, and 3 of 5 (60%) undifferentiated carcinomas showed an activation of N-RAS proto-oncogene. Interestingly, two primary follicular tumors and their corresponding bone metastases, showed N-ras mutations. In the same cases we evaluated the expression of thyroglobulin by immunohistochemical analysis. Although the majority of well-differentiated carcinomas expressed a high level of thyroglobulin, the expression of the same antigen was absent or only occasional weakly positive in 33 of 44 poorly differentiated carcinomas. Interestingly, N-ras mutation was restricted to the group of tumours with low or absent thyroglobulin expression, suggesting that this genetic change is prevalent in less differentiated tumors.

Bone Neoplasms↗
PubMed2000

Conditional apoptosis induced by oncogenic ras in thyroid cells.

Mutations of ras are tumor-initiating events for many cell types, including thyrocytes. To explore early consequences after oncogenic Ras activation, we developed a doxycycline-inducible expression system in rat thyroid PCCL3 cells. Beginning 3-4 days after H-Ras(v12) expression, cells underwent apoptosis. The H-Ras(v12) effects on apoptosis were decreased by a mitogen-activated protein kinase kinase (MEK1) inhibitor and recapitulated by doxycycline-inducible expression of an activated MEK1 mutant (MEK1(S217E/S221E)). As reported elsewhere, acute expression of H-Ras(v12) also induces mitotic defects in PCCL3 cells through ERK (extracellular ligand-regulated kinase) activation, suggesting that apoptosis may be secondary to DNA damage. However, acute activation of SAPK/JNK (stress-activated protein kinase/Jun N-terminal kinase) through acute expression of Rac1(v12) also triggered apoptosis, without inducing large-scale genomic abnormalities. H-Ras(v12)-induced apoptosis was dependent on concomitant activation of cAMP by either TSH or forskolin, in a protein kinase A-independent manner. Thus, coactivation of cAMP-dependent pathways and ERK or JNK (either through H-Ras(v12), Rac1(v12), or MEK1(S217E/S221E)) is inconsistent with cell survival. The fate of thyrocytes within the first cell cycles after expression of oncogenic Ras is dependent on ambient TSH levels. If both cAMP and Ras signaling are simultaneously activated, most cells will die. Those that survive will eventually lose TSH responsiveness and/or inactivate the apoptotic cascade through secondary events, thus enabling clonal expansion.

Animals↗
PubMed1999

Involvement of protein kinase Cepsilon (PKCepsilon) in thyroid cell death. A truncated chimeric PKCepsilon cloned from a thyroid cancer cell line protects thyroid cells from apoptosis.

The protein kinase C (PKC) family has been implicated in the regulation of apoptosis. However, the contribution of individual PKC isozymes to this process is not well understood. We reported amplification of the chromosome 2p21 locus in 28% of thyroid neoplasms, and in the WRO thyroid carcinoma cell line. By positional cloning we identified a rearrangement and amplification of the PKCepsilon gene, that maps to 2p21, in WRO cells. This resulted in the overexpression of a chimeric/truncated PKCepsilon (Tr-PKCepsilon) mRNA, coding for N-terminal amino acids 1-116 of the isozyme fused to an unrelated sequence. Expression of the Tr-PKCepsilon protein in PCCL3 cells inhibited activation-induced translocation of endogenous PKCepsilon, but its kinase activity was unaffected, consistent with a dominant negative effect of the mutant protein on activation-induced translocation of wild-type PKCepsilon and/or displacement of the isozyme to an aberrant subcellular location. Cell lines expressing Tr-PKCepsilon grew to a higher saturation density than controls. Moreover, cells expressing Tr-PKCepsilon were resistant to apoptosis, which was associated with higher Bcl-2 levels, a marked impairment in p53 stabilization, and dampened expression of Bax. These findings point to a role for PKCepsilon in apoptosis-signaling pathways in thyroid cells, and indicate that a naturally occurring PKCepsilon mutant that functions as a dominant negative can block cell death triggered by a variety of stimuli.

Amino Acid Sequence↗
PubMed1999

Thyroid consequences of the Chernobyl nuclear accident.

It is well recognized that the use of external irradiation of the head and neck to treat patients with various non-thyroid disorders increases their risk of developing papillary thyroid carcinoma years after radiation exposure. An increased risk of thyroid cancer has also been reported in survivors of the atomic bombs in Japan, as well as in Marshall Island residents exposed to radiation during the testing of hydrogen bombs. More recently, exposure to radioactive fallout as a result of the Chernobyl nuclear reactor accident has clearly caused an enormous increase in the incidence of childhood thyroid carcinoma in Belarus, Ukraine, and, to a lesser extent, in the Russian Federation, starting in 1990. When clinical and epidemiological features of thyroid carcinomas diagnosed in Belarus after the Chernobyl accident are compared with those of naturally occurring thyroid carcinomas in patients of the same age group in Italy and France, it becomes apparent that the post-Chernobyl thyroid carcinomas were much less influenced by gender, virtually always papillary (solid and follicular variants), more aggressive at presentation and more frequently associated with thyroid autoimmunity. Gene mutations involving the RET proto-oncogene, and less frequently TRK, have been shown to be causative events specific for papillary cancer. RET activation was found in nearly 70% of the patients who developed papillary thyroid carcinomas following the Chernobyl accident. In addition to thyroid cancer, radiation-induced thyroid diseases include benign thyroid nodules, hypothyroidism and autoimmune thyroiditis, with or without thyroid insufficiency, as observed in populations after environmental exposure to radioisotopes of iodine and in the survivors of atomic bomb explosions. On this basis, the authors evaluated thyroid autoimmune phenomena in normal children exposed to radiation after the Chernobyl accident. The results demonstrated an increased prevalence of circulating thyroid antibodies not associated with significant thyroid dysfunction. This finding is consistent with the short period of follow-up, but it is highly likely that these children will develop clinical thyroid autoimmune diseases in the future. Therefore, screening programmes for this at-risk population should focus, not only on the detection of thyroid nodules and cancer, but also on the development of thyroid autoimmune diseases.

Autoimmunity↗
PubMed1998

Genetic and epigenetic alterations of the cyclin-dependent kinase inhibitors p15INK4b and p16INK4a in human thyroid carcinoma cell lines and primary thyroid carcinomas.

BACKGROUND: D-type cyclins, in association with the cyclin-dependent kinases CDK4 and CDK6, promote progression through the G1 phase of the cell cycle. CDK activity is modulated by inhibitors such as p15INK4b and p16INK4a. Loss of function of p15INK4b and p16INK4a (multiple tumor suppressor-I and CDK4 inhibitor) determines impairment in the control of the cell cycle and contributes to the transformation of several cell types. METHODS: The authors examined 20 thyroid neoplasms (12 papillary carcinomas and 8 follicular adenomas) and 4 human thyroid carcinoma cell lines for gene mutations and epigenetic modifications of the p15INK4b and p16INK4a genes by Southern blot analysis, single strand conformation polymorphism, and a polymerase chain reaction-based methylation assay. RESULTS: Abnormalities of p16 were found in the four cell lines studied. In follicular carcinoma (WRO) cells, both the p15 and p16 genes were homozygously deleted. Undifferentiated carcinoma (FRO) cells had a nonsense point mutation at codon 72 (CGA-TGA, Arg-Stop) of p16, whereas the poorly differentiated papillary carcinoma (NPA) line harbored a point mutation at the exon 1-intron 1 boundary that altered the donor splicing site and caused an aberrantly spliced form of p16INK4a. Furthermore, p16 allelic loss was evident in the DNA of both FRO and NPA cells. Finally, p16 expression was absent in the ARO cell line, likely due to a de novo methylation of exon 1 of p16INK4a. Regarding the primary thyroid tumors, a missense point mutation at codon 91 was found in 1 of 12 papillary thyroid carcinomas (GCC-GTC, Ala-Val). No mutations were found in follicular adenomas. However, in 6 of 20 primary tumors there was hypermethylation at exon 1 of p16. CONCLUSIONS: The high prevalence of p15 and p16 mutations in the cell lines described suggests involvement of these genes in immortalization in vitro. The p16 defects may have preexisted in a small subclone of the primary tumor that were selected for in vitro. Alternatively, p16 mutations may have arisen de novo during cell culture. Mutations of p15INK4b and p16INK4a do not appear to be critical events in the development of follicular adenomas or papillary carcinomas. However, de novo methylation of the 5' CpG island of p16 is common in primary tumors, indicating that the function of this gene may be lost as an epigenetic event during disease progression.

Adenoma↗
PubMed1997

Identification of rapid turnover transcripts overexpressed in thyroid tumors and thyroid cancer cell lines: use of a targeted differential RNA display method to select for mRNA subsets.

The mRNAs of transiently expressed proteins such as cytokines and proto-oncogenes are commonly subject to rapid transcriptional activation and degradation. Transcript turnover is determined in part by association of certain proteins with consensus AU-rich motifs (AUUUA) in the 3'-untranslated region of the transcripts. Here we report a modification of differential RNA display (DRD) to detect differentially expressed rapid turnover mRNAs containing AU-rich motifs from thyroid cancer tissues and cell lines. RNA of normal and thyroid cancer tissues was differentially displayed using a 3'anchor primer to the poly(A) tail and an arbitrary 5'primer incorporating an AUUUA sequence. The appropriateness of the strategy was established by its ability to display known early response genes, such as c- fos, using partially degenerate primers. To test whether the novel cDNAs isolated coded for transcripts subject to rapid turnover, they were used as probes for Northern blots of RNA from clonal human thyroid carcinoma cell lines treated for varying periods with either cycloheximide or actinomycin D. A number of novel differentially expressed cDNA fragments were isolated from human papillary thyroid carcinoma tissues, among them a cDNA with zinc finger motifs and homology to other zinc finger proteins. Using this fragment to probe a cDNA library, a full-length cDNA (ZnF20) was isolated that was 4333 bp in length and contained an open reading frame of 1029 amino acids. The ZnF20 cDNA hybridized to multiple transcripts in a thyroid cancer cell line (8.0, 4.5 and 2 kb) that increased after cycloheximide treatment and decayed <2 h after addition of actinomycin D. The ZnF20 mRNA was overexpressed in three of six thyroid papillary carcinomas as compared with paired normal thyroid tissue controls. The data presented here support the use of a targeted DRD approach for the isolation of rapid turnover mRNAs, many of which may be interesting candidate oncogenes.

Amino Acid Sequence↗
PubMed1996

Transfection with the cDNA of the human thyrotropin receptor of a poorly differentiated rat thyroid cell line (FRT).

A cell line derived from the Fisher rat thyroid (FRT), that does not have functional TSH receptor, was stably transfected with the cDNA of the human TSH receptor (h TSH-R). In wild FRT cells TSH (1-1000 mU/l) was unable to increase cAMP production, while 10-10000 nmol/l forskolin elicited a 10-30 fold cAMP stimulation. Two of the transfected clones were responsive to TSH in terms of cAMP production. In particular, the FRT-R3 transfected clone showed the highest sensitivity to the hormone with a 10 fold cAMP increase over the basal at 100 mU/l TSH. The Northern blot analysis using a 2.4 kbp cDNA probe for the hTSH-R showed a band corresponding to the mRNA of TSH receptor in FRT-R3 cells, but not in wild FRT cells. In both cell types TSH was ineffective in stimulating growth assayed by 3H-thymidine incorporation into DNA. Hybridization with a probe for thyroperoxidase on polymerase chain reaction products after reverse transcription of mRNA showed that FRT-R3, as well as FRT cells, do not have a transcript for thyroperoxidase. In conclusion, the data reported in this paper show that the insertion of the hTSH-R cDNA in the genome of poorly differentiated rat thyroid cells results in the recovery of TSH-dependent adenylate cyclase, but not other differentiated thyroid cell functions.

Adenylyl Cyclases↗
PubMed1996

Structural studies of the thyrotropin receptor and Gs alpha in human thyroid cancers: low prevalence of mutations predicts infrequent involvement in malignant transformation.

The genes for either the TSH receptor (TSH-R) or the stimulatory guanine nucleotide-binding protein subunit (Gs alpha) can undergo somatic mutations in thyroid cells, leading to constitutive activation of adenylyl cyclase and the formation of clonal hyperfunctioning thyroid adenomas. Autonomously functioning thyroid adenomas are thought not to be common precursors of thyroid cancer. If this is the case, mutations of the TSH-R or Gs alpha would not be expected to be highly prevalent in thyroid carcinomas. In this paper we report the results of a screen for structural defects in exon 10 of the TSH-R (which includes the whole serpentine structure, but not the extracellular domain) and of Gs alpha in 30 thyroid carcinomas. Five of these were from patients with functioning metastasis, as we hypothesized that if mutations of these genes were to play a role in the progression to malignancy, they would be more likely to manifest in thyroid cancers that retain unusual differentiated function (i.e. capable of synthesizing enough thyroid hormone to render patients euthyroid or hyperthyroid after total thyroidectomy). None of the 30 tumors had activating point mutations of Gs alpha. Only 2 of 30 had somatic mutations of the TSH-R (codon 632: ACC to GCC, Thr to Ala; and ACC to ATC, Thr to Ile, respectively), the latter in a patient with a thyroid hormone-producting follicular carcinoma. These results suggest that events leading to constitutive activation of the adenylate cyclase signal transduction cascade are not a frequent event in the progression toward differentiated thyroid carcinomas.

Base Sequence↗
PubMed1996

Somatic mutations of the ret protooncogene in sporadic medullary thyroid carcinoma are not restricted to exon 16 and are associated with tumor recurrence.

Germline point mutations in exons 10, 11, and 16 of the ret protooncogene have been identified as causative in multiple endocrine neoplasia type 2 and in familial medullary thyroid carcinoma (MTC). Somatic point mutations of the same gene, exclusively associated with codon 918 of exon 16, have also been reported in few cases of sporadic medullary thyroid carcinoma. We analyzed the blood and tumor DNA of 19 patients with sporadic MTC and 6 patients with primary parathyroid adenoma for point mutations at exons 10, 11, and 16 of the ret protooncogene by restriction analysis of the PCR-amplified product and by sequence analysis of exons 10 and 11. A Cys634-->Tyr mutation was found in both the tumoral and blood DNA of one patient, indicating that he was affected by an hereditary form of MTC, erroneously considered sporadic. In the other 18 patients with MTC, somatic point mutations of ret were found in 8 cases (44.4%). In 5 cases the mutation affected exon 16 (Met918-->Thr), and in 3 cases it affected exon 11 (Cys634-->Arg in 1 and Cys634-->Trp in 2); these 3 mutations were confirmed by sequence analysis. The remaining 10 patients had no mutation in exon 10 by either restriction analysis or sequence analysis. Clinical data showed that 75% of the patients whose tumor carried ret mutation had tumor recurrence and/or increased serum calcitonin concentrations during the postsurgical follow-up period as opposed to 10% of the patients without mutations (P < 0.02, by chi2 analysis). No ret mutation was found in the tumoral DNA from parathyroid adenomas. Our findings indicate that the somatic ret point mutation frequently found in sporadic MTC may affect not only exon 16 but also exon 11 and is associated with less favorable clinical outcome.

Adult↗
PubMed1995

Early treatment of hereditary medullary thyroid carcinoma after attribution of multiple endocrine neoplasia type 2 gene carrier status by screening for ret gene mutations.

BACKGROUND: Germline missense point mutations of the ret proto-oncogene have been shown as causative in multiple endocrine neoplasia type 2 (MEN 2A and 2B) and in familial medullary thyroid carcinoma (FMTC). Most of the mutations are found in exon 10, 11, or 16 of the gene and are easily recognized by restriction analysis. METHODS: Using restriction analysis, we screened 58 subjects from nine kindreds. RESULTS: Family members (n = 16) already known to be affected with the disease carried the germline mutation. Among the 42 subjects apparently unaffected, 37 were not gene carriers and 5 were gene carriers. Basal and pentagastrin-stimulated serum calcitonin levels were normal in two patients and abnormal in three. All patients were treated with total thyroidectomy and central node dissection. In all cases multiple foci of MTC were shown at histologic examination. CONCLUSIONS: Our data indicate that genetic screening of MEN2 pedigrees allows the early identification of gene carriers. Because surgery of MTC in the preclinical phase has high probability of curing these patients, we suggest genetic screening soon after birth and total thyroidectomy in gene carriers as early as possible.

Base Sequence↗
PubMed1995

Molecular biology studies on mesothelioma tumor samples: preliminary data on H-ras, p21, and SV40.

The ras gene is one of the oncogenes most commonly detected in human cancers; this protooncogene is converted to active oncogene by point mutations occurring at either codon 12, 13, or 61. SV40 is a DNA-transforming simian virus, a 105 bp sequence of which has been shown recently to be present in a significant fraction of human mesothelioma cells. Eleven human malignant mesotheliomas were examined for H-ras gene mutations at codon 12, 13, and 61 and for the presence of SV40-like sequences. DNA prepared from formalin-fixed and paraffin-embedded tissue was amplified by means of PCR and analyzed using designed restriction fragment length polymorphism. No mutation with respect to H-ras was found in any tumor sample, but the majority of mesothelioma cells contained SV40-like sequences.

Adult↗
PubMed1994

Expression of p21 ras protein as a prognostic factor in papillary thyroid cancer.

We studied the expression of p21, the ras encoded protein, in primary tumour of 45 patients with papillary thyroid cancer (PTC). Patients were grouped according to outcome so that one group (31 patients) had a good outcome and the other (14 patients) a fatal outcome, after a follow-up of at least 5 years. The presence of p21 ras protein was assessed by immunohistochemistry with a specific monoclonal antibody (MAb Y-13259). The results were correlated with the outcome, with the expression of proliferating cell nuclear antigen (PCNA)/cyclin (as a marker of cell proliferation) and with other well established prognostic factors for PTC (age, grading, extension and tumour size; Endocrinol Metab Clin North Am 1990, 19, 545-576). p21 staining in tumours of living patients was negative in 15, weakly positive (1+) in 10 and strongly positive (2+ or more) in 6 patients. In tumours from deceased patients, p21 staining was negative in 1, weakly positive in 2 and strongly positive in the remaining 11 patients (P < 0.001, chi 2). PCNA immunostaining was increased in 63.6% (7/11) of the tumours from deceased patients compared to 17.8% (5/28) of the tumours of living patients, but no direct correlation was found between p21 and PCNA expression. Among the other prognostic factors studied, only age > or = 40 years was a significant predictor of poor outcome. The survival curve of patients with strongly positive p21 staining was similar to that of patients aged > or = 40 years at the time of diagnosis. The combination of p21 > or = 2+ and age > or = 40 was superior to age alone (P < 0.05) as a prognostic indicator of poor outcome. In conclusion, our results indicate that the p21 product of the ras (proto)oncogene is differently expressed in PTC, in relation to the degree of aggressiveness. Regardless of the pathogenetic role of the ras oncogene in thyroid tumorigenesis, our data indicate that the expression of the p21 ras protein may be regarded as a prognostic indicator in PTC. Furthermore, overexpression of p21 ras protein is associated with patients in the older age groups, and might contribute to the poor prognosis of elderly patients.

Adolescent↗
PubMed1994

T cell responses to orbital antigens in thyroid-associated ophthalmopathy.

Thyroid-associated ophthalmopathy (TAO) is most likely to be a T cell-mediated disease, in which cytokines released in the extraocular muscles activate fibroblasts, increasing glycosaminoglycan production. The nature of the orbital antigen recognized by the infiltrating T cells is unclear, although it is possible that there is cross-reactivity between this and a thyroid autoantigen to explain the close association with thyroid autoimmunity. We have tested the ability of human and porcine eye muscle antigen preparations to stimulate proliferation of circulating T cells from healthy subjects and patients with TAO or Graves' disease without clinical TAO. Occasional responses were seen, particularly after depletion of CD8+ T cells, and two out of 10 TAO patients responded to eye muscle proteins of 25-50 kD after fractionation of antigens on gels and subsequent elution. There was no disease-specific response of T cells to R1, R14, D1 and 1D3, recombinant proteins identified from screening an eye muscle cDNA library with sera from patients with autoimmune thyroid disease. We have also found that interferon-gamma (IFN-gamma) production by T cells from TAO patients was not stimulated by eye muscle membrane antigens or by 1D3. These results suggest that the frequency of circulating T cells responding to eye muscle antigens in TAO is low, and that several candidate orbital antigens, including the 64-kD protein 1D3, are unlikely to be important T cell autoantigens in this condition.

Animals↗
PubMed1994

Routine measurement of serum calcitonin in nodular thyroid diseases allows the preoperative diagnosis of unsuspected sporadic medullary thyroid carcinoma.

To assess whether routine measurement of serum calcitonin (CT) could improve the preoperative diagnosis of sporadic medullary thyroid carcinoma (MTC), 1385 consecutive patients presenting for nodular thyroid disease during the year 1991 were submitted to serum CT determination and fine needle aspiration cytology (FNAC). The clinical diagnosis was nontoxic nodular goiter in 1197 (86.4%) patients, toxic multinodular goiter in 65 (4.7%), autonomously functioning thyroid nodule (AFTN) in 64 (4.6%), and autoimmune thyroid disease (Graves' disease or Hashimoto's thyroiditis) with nodule(s) in 59 (4.3%). As controls, 177 patients with nonnodular thyroid disease and 32 normal subjects were also studied. Patients with FNAC suspicious of any kind of thyroid carcinoma and patients with elevated basal and pentagastrin-stimulated serum CT, regardless of the results of FNAC, were submitted to surgery. Eight (0.57%) patients (7 with nontoxic nodular goiter and 1 with AFTN) had elevated basal serum CT levels, ranging between 55-10,000 pg/mL. The pentagastrin test was abnormal in all of them. FNAC was suggestive of MTC in 2, thyroid carcinoma in 1, benign nodule in 3, and inadequate in 2. By histology, immunohistochemistry, and Northern blot analysis of total tumor RNAs, MTC was confirmed in all patients, including the 1 with AFTN, who had the association of microfollicular adenoma and a small MTC in the same lobe. After surgery, serum CT decreased to undetectable levels in 7 patients and remained undetectable in 6 of them during a mean follow-up of 22 months, although 1 of them had a positive response to pentagastrin. Forty-four patients in the group with normal serum CT levels had FNAC suspicious for differentiated thyroid carcinoma and were treated by surgery. Differentiated thyroid carcinoma, mostly papillary, was confirmed at histology in 43 subjects (3.1% of all thyroid nodules). In conclusion, the results of our study indicate that serum CT measurement is useful for the screening of sporadic MTC in patients with thyroid nodule(s). The prevalence of MTC, diagnosed by serum CT measurement in a 12-month period, among an unselected series of 1385 patients with nodular thyroid disease was surprisingly high: 0.57% of all thyroid nodules and 15.7% of all thyroid carcinomas. Serum CT measurement was superior to FNAC in suggesting the diagnosis of MTC and was devoid of falsely positive results. Increasing the diagnostic accuracy helped the surgeon to perform more radical treatment of MTC, thus achieving frequent normalization of postoperative serum CT levels. Whether this result indicates definitive cure remains to be established on the basis of longer follow-up.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1994

Expression of thyrotropin receptor (TSH-R), thyroglobulin, thyroperoxidase, and calcitonin messenger ribonucleic acids in thyroid carcinomas: evidence of TSH-R gene transcript in medullary histotype.

We studied the expression of the TSH receptor (TSH-R), thyroglobulin (Tg), thyroperoxidase (TPO), and calcitonin (CT) genes in a total of 53 tissues from 30 patients with thyroid carcinoma and from 9 patients with benign thyroid diseases. By Northern blot analysis of total RNA preparations, CT mRNA was expressed in all cases (n = 6) of medullary thyroid carcinoma (MTC). Surprisingly, 3 of them expressed the TSH-R mRNA, in association with the Tg and TPO mRNAs in 1. The presence of the TSH-R transcript in the neoplastic C-cells was confirmed in 1 MTC by in situ hybridization using a mixture of 3 oligonucleotide probes derived from dog TSH-R cDNA. With various degrees of expression, all differentiated thyroid carcinomas (20 papillary and 2 follicular) expressed TSH-R, Tg, and TPO, but not CT mRNAs. On the contrary, samples from 2 patients with anaplastic carcinoma did not express TSH-R, Tg, or TPO mRNA, but 1 of them expressed CT mRNA. All of the transcripts obtained from thyroid carcinomas (both primary and metastatic) were of the same size as the transcripts from normal or benign thyroid tissues, with the exception of 2 cases of differentiated thyroid cancer, in which TSH-R mRNA of lower mol wt (approximately 4.0 kilobases) was found in the absence of alteration in cDNA size and restriction map. The main conclusions of our study are that 1) the TSH-R gene is expressed in some MTC, which supports, at molecular level, the hypothesis of the existence of mixed follicular-medullary thyroid tumors; and 2) the expression of TSH-R, Tg, and TPO in undifferentiated thyroid cancer is lost.

Blotting, Northern↗