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Context Current guidelines recommend a selective use of radioiodine treatment (RAI) for papillary thyroid cancer (PTC). Objective This work aimed to determine how policy changes affect the use of RAI and the short-term outcomes of patients. Methods A retrospective analysis of longitudinal data was conducted in an academic referral center of patients with nonaggressive PTC variants; no extrathyroidal invasion or limited to soft tissues, no distant metastases, and 5 or fewer central-compartment cervical lymph node metastases. In cohort 1, standard treatments were total thyroidectomy and RAI (May 2005-June 2011); in cohort 2 decisions on RAI were deferred for approximately 12 months after surgery (July 2011-December 2018). Propensity score matching was used to adjust for sex, age, tumor size, lymph node status, and extrathyroidal extension. Intervention included immediate RAI or deferred choice. Main outcome measures were responses to initial treatment during 3 or more years of follow-up. Results In cohort 1, RAI was performed in 50 of 116 patients (51.7%), whereas in cohort 2, it was far less frequent: immediately in 10 of 156 (6.4%), and in 3 more patients after the first follow-up data. The frequencies of structural incomplete response were low (1%-3%), and there were no differences between the 2 cohorts at any follow-up visit. Cohort 2 patients had higher rates of “gray-zone responses” (biochemical incomplete or indeterminate response). Conclusion Selective use of RAI increases the rate of patients with “uncertain” status during early follow-up. The rate of structural incomplete responses remains low regardless of whether RAI is used immediately. Patients should be made aware of the advantages and drawbacks of omitting RAI.

Context The prevalence of thyroid nodules in the general population is increasingly high, and at least half of those biopsied prove to be benign. Sonographic risk-stratification systems are being proposed as “rule-out” tests that can identify nodules that do not require fine-needle aspiration (FNA) cytology. Objective To comparatively assess the performances of five internationally endorsed sonographic classification systems [those of the American Thyroid Association, the American Association of Clinical Endocrinologists, the American College of Radiology (ACR), the European Thyroid Association, and the Korean Society of Thyroid Radiology] in identifying nodules whose FNAs can be safely deferred and to estimate their negative predictive values (NPVs). Design Prospective study of thyroid nodules referred for FNA. Setting Single academic referral center. Patients Four hundred seventy-seven patients (358 females, 75.2%); mean (SD) age, 55.9 (13.9) years. Main Outcome Measures Number of biopsies classified as unnecessary, false-negative rate (FNR), sensitivity, specificity, predictive values, and diagnostic ORs for each system. Results Application of the systems’ FNA criteria would have reduced the number of biopsies performed by 17.1% to 53.4%. The ACR Thyroid Imaging Reporting and Data System (TIRADS) allowed the largest reduction (268 of 502) with the lowest FNR (NPV, 97.8%; 95% CI, 95.2% to 99.2%). Except for the Korean Society of Thyroid Radiology TIRADS, all other systems exhibited significant discriminatory performance but produced significantly smaller reductions in the number of procedures. Conclusions Internationally endorsed sonographic risk stratification systems vary widely in their ability to reduce the number of unnecessary thyroid nodule FNAs. The ACR TIRADS outperformed the others, classifying more than half the biopsies as unnecessary with a FNR of 2.2%.

Context: Indoleamine 2,3-dioxygenase 1 (IDO1) is a single chain oxidoreductase that catalyzes tryptophan degradation to kynurenine. In cancer, it appears to exert an immunosuppressive function as part of an acquired mechanism of immune escape mediated by the inhibition of lymphocyte proliferation and survival and by the induction of FoxP3+ T regulatory cells. Objective: The objective of the study was to evaluate IDO1 expression in thyroid carcinoma and demonstrate its immunosuppressive function in the context of thyroid tumors. Setting: IDO1 expression was evaluated by quantitative PCR in 105 papillary thyroid carcinomas (PTCs), 11 medullary thyroid carcinomas, six anaplastic thyroid carcinomas, and five thyroid carcinoma cell lines (TCCLs), by immunohistochemistry in 55 PTCs and by Western blotting in five TCCLs. FoxP3+ Treg lymphocyte density was evaluated by immunohistochemistry in 29 PTCs. IDO1 inhibitory effect on lymphocyte proliferation was tested in coculture experiments of TCCLs and activated lymphocytes. Results: IDO1 mRNA expression resulted significantly higher in all the analyzed thyroid carcinoma histotypes compared with normal thyroid. Interestingly, an increase of IDO1 mRNA expression magnitude could be observed with gain of aggressiveness (PTCs and medullary thyroid carcinomas ≪ anaplastic thyroid carcinomas). In PTCs, IDO1 mRNA expression magnitude correlated with IDO1 immunostaining intensity in cancer cells and with FoxP3+ Treg lymphocyte density in the tumor microenvironment. IDO1 was expressed in human thyroid cancer cell lines in vitro, and FTC-133 cells showed high kynurenine concentration in the conditioned medium and a strong suppressive action on the proliferation of activated lymphocytes in coculture experiments. Conclusions: For the first time, this study demonstrates a pivotal role of IDO1 in the suppression of lymphocyte function in thyroid carcinoma microenvironment.

Serum thyroglobulin (Tg) assays are considered fundamental in postoperative surveillance of differentiated thyroid cancer (DTC) patients. However, the postsurgical profile of Tg levels has never been specifically investigated in patients who do not undergo radioiodine remnant ablation (RRA).Our objective was to explore the evolution of Tg levels over time in DTC patients treated with total or near-total thyroidectomy without RRA.We retrospectively analyzed 290 consecutively diagnosed cases of low-risk (American Thyroid Association criteria) DTC treated with thyroidectomy alone and followed yearly with neck ultrasonography and serum Tg assays. We compared final Tg values in this group and a matched group of 495 RRA-positive patients. Temporal trends of serial Tg levels were also analyzed in 78 of the RRA-negative patients monitored with a high-sensitivity immunoradiometric assay.After follow-up of 2.5-22 yr (median 5 yr), final Tg levels were undetectable (1 ng/ml) in 274 of 290 RRA-negative patients (95%) and 492 of 495 RRA-positive controls (99%). In the subset of 78 RRA-negative patients, undetectable Tg levels (0.2 ng/ml) were recorded in 60% at the first postoperative evaluation (3-12 months) and in 79% after 5 yr. Tg levels increased in the single patient who experienced disease recurrence during the observation period.In most RRA-negative patients, postoperative serum Tg values spontaneously drop to undetectable levels within 5-7 yr after thyroidectomy. Thus, in later phases, Tg assays may be a valuable tool for follow-up even in patients who do not undergo RRA.

Throughout the world, small, differentiated thyroid cancers—papillary thyroid carcinomas (PTC) for the most part—are being diagnosed with growing frequency, an effect that can be attributed largely to technological advances in diagnostic imaging and greater diagnostic scrutiny (1). In most cases, the risk of disease recurrence and tumor-related mortality after total or near-total thyroidectomy appears to be quite low, and for this reason postoperative radioiodine remnant ablation (RRA) is being omitted in an increasingly large percentage of patients with PTC (2). This strategy, which tailors case management to individual risk levels, is in keeping with the 2009 American Thyroid Association (ATA) guidelines (3), which encourage more selective use of postoperative RRA. The challenge, however, is to find an effective approach for the postoperative follow-up of patients who have undergone total or near-total thyroidectomy without RRA. Although the outcome of these “low risk” PTC is almost invariably favorable, the patients still require regular, long-term surveillance. Indeed, persistent or recurrent disease can also occur in patients with early-stage tumors, and relapses have been reported as late as 10 yr after diagnosis (4). Effective postsurgical follow-up of patients thought to be disease-free should be capable of detecting recurrences: 1) early (when the chances of a cure are greatest); 2) with high sensitivity and specificity; and 3) with a high negative predictive value. Ideally, it should also allow us to identify—at some point—cases with a low enough likelihood of recurrence to justify less intensive surveillance, which would be not only more cost-effective but also easier on the patient (physically and psychologically). The 2009 ATA guidelines recommend that periodic serum thyroglobulin assay and neck ultrasonography (US) “be considered” during the follow-up of patients whose differentiated thyroid cancers have been managed with subtotal thyroidectomy or with total thyroidectomy not followed by RRA (recommendation 44) (3). However, little distinction is made between these two methods, and few details are offered on their respective merits or shortcomings and how and when each might be used. Serum thyroglobulin assays after exogenous or endogenous TSH stimulation are considered the mainstay cornerstone of postoperative surveillance programs for patients with PTC (3). Indeed, detectable TSH-stimulated thyroglobulin levels or increases over time in their values are a highly specific marker of residual/recurrent disease for patients treated with postoperative RRA (3, 5); until recently, this included virtually all of those who were treated for PTC. What we know about the diagnostic value of serum thyroglobulin assays is largely based on their performance in this population after TSH stimulation. But for patients who do notundergoRRA,theseassaysaremoredifficult to interpret. Detectable thyroglobulin production in these cases may well originate exclusively from the remnant of normal thyroid tissue leftafter surgery,andtheboundariesbetween“normal and neoplastic production” have never been specifically investigated in this population. Consequently, for a rapidly growing subset of PTC patients, serum thyroglobulin assays currently have some important limitations as postoperative follow-up tools. By contrast, neck sonography has a number of features that are valuable in the postoperative follow-up of PTC patients (5–8). Persistent or recurrent disease is almost always associated with spread to the cervical lymph nodes

Context: Notch genes encode receptors for a signaling pathway that regulates cell growth and differentiation in various contexts, but the role of Notch signaling in thyroid follicular cells has never been fully published. Objective: The objective of the study was to characterize the expression of Notch pathway components in thyroid follicular cells and Notch signaling activities in normal and transformed thyrocytes. Design/Setting and Patients: Expression of Notch pathway components and key markers of thyrocyte differentiation was analyzed in murine and human thyroid tissues (normal and tumoral) by quantitative RT-PCR and immunohistochemistry. The effects of Notch overexpression in human thyroid cancer cells and FTRL-5 cells were explored with analysis of gene expression, proliferation assays, and experiments involving transfection of a luciferase reporter construct containing human NIS promoter regions. Results: Notch receptors are expressed during the development of murine thyrocytes, and their expression levels parallel those of thyroid differentiation markers. Notch signaling characterized also normal adult thyrocytes and is regulated by TSH. Notch pathway components are variably expressed in human normal thyroid tissue and thyroid tumors, but expression levels are clearly reduced in undifferentiated tumors. Overexpression of Notch-1 in thyroid cancer cells restores differentiation, reduces cell growth rates, and stimulates NIS expression via a direct action on the NIS promoter. Conclusion: Notch signaling is involved in the determination of thyroid cell fate and is a direct regulator of thyroid-specific gene expression. Its deregulation may contribute to the loss of differentiation associated with thyroid tumorigenesis.

Although the prognosis of papillary thyroid microcarcinoma (PTMC) is usually excellent, the optimal follow-up strategy has never been investigated.The objective of the study was to investigate the role of neck ultrasonography (US), whole-body scintigraphy (WBS), and serum thyroglobulin levels (Tg) after recombinant human (rh) TSH in the follow-up of very low-risk PTMC patients.The study was a 5-yr observational study based on a 6- to 12-month follow-up after near total thyroidectomy.The study population consisted of ambulatory patients.Eighty consecutive patients diagnosed with PTMC, who had not undergone postoperative radioiodine treatment because of unifocal tumor without lymph node metastases and who did not have anti-Tg antibodies, were included.WBS and Tg after both rhTSH and neck US were measured.rhTSH-Tg was 1 ng/ml or less in 45 (Tg-) and more than 1 in 35 (Tg+) patients. WBS showed no pathological uptake in any patient. US identified node metastases in two Tg (+) and one Tg (-) patients. rhTSH-Tg levels positively correlated with thyroid bed iodine uptake (r = 0.40, P0.0001). To date (32 +/- 13 months after surgery), all node-negative patients have undetectable Tg levels on LT(4) treatment and negative US.For the initial follow-up of PTMC patients without risk factors and anti-Tg antibodies and who did not undergo radioiodine treatment: 1) WBS is useless; 2) US is highly sensitive in detecting node metastases; and 3) detectable rhTSH-Tg levels mainly depend on small normal tissue remnants. In this subgroup of PTMC patients, neck US might be regarded as a primary tool for the initial follow-up.

Context: Evidence from in vitro studies or animal models has shown that TSH affects thyrocytes by thyroid-specific expression modulation.Objective: The objective of our study was to analyze the role of TSH in human thyroid gene expression in vivo.Design/Setting: Thirty-nine normal thyroid tissues were collected at the same center.Study Subjects: Patients were divided into two groups based on serum TSH levels: 17 with normal TSH levels (1–4 mU/liter; group 1) and 22 with TSH levels below 0.5 mU/liter (group 2).Intervention: Group 2 underwent thyroidectomy after suppressive l-T4 therapy.Main Outcome Measures: mRNA levels of thyroid genes such as sodium/iodide symporter (NIS), apical iodide transporter, pendrin, thyroglobulin, thyroperoxidase, TSH receptor, paired box transcription factor 8, and thyroid transcription factor-1 were evaluated by quantitative PCR.Results: The reduction of TSH stimulation causes decreases in NIS and apical iodide transporter gene expression in normal tissues and more limited reductions in thyroglobulin, thyroperoxidase, and paired box transcription factor 8, but it has no significant effect on TSH receptor, pendrin, or thyroid transcription factor-1. Comparison of NIS levels in normal and nodular tissues from the same patient confirmed that it is differentially expressed in nodules only in the presence of normal TSH (P < 0.01). In patients with suppressed TSH, nodular NIS levels were similar to those in normal tissues.Conclusions: Our data represent the first demonstration in human thyroid tissues that TSH contributes to the regulation of thyrocyte differentiation by modulating thyroid gene levels. It exerts a particularly important effect on the transcription of NIS, which becomes very low after prolonged TSH suppression.

The gene recently cloned that is responsible for the Pendred syndrome (PDS), an autosomal recessive disease characterized by goiter and congenital sensorineural deafness, is mainly expressed in the thyroid gland. Its product, designated pendrin, was shown to transport chloride and iodide. To investigate whether the PDS gene is altered during thyroid tumorigenesis, PDS gene expression and pendrin expression were studied using real-time kinetic quantitative PCR and antipeptide antibodies, respectively, in normal, benign, and malignant human thyroid tissues. The results were then compared to those observed for sodium/iodide symporter (NIS) expression. In normal tissue, pendrin is localized at the apical pole of thyrocytes, and this in contrast to the basolateral location of NIS. Immunostaining for pendrin was heterogeneous both inside and among follicles. In hyperfunctioning adenomas, the PDS messenger ribonucleic acid level was in the normal range, although immunohistochemical analysis showed strong staining in the majority of follicular cells. In hypofunctioning adenomas, mean PDS gene expression was similar to that detected in normal thyroid tissues, but pendrin immunostaining was highly variable. In thyroid carcinomas, PDS gene expression was dramatically decreased, and pendrin immunostaining was low and was positive only in rare tumor cells. This expression profile was similar to that observed for the NIS gene and its protein product. In conclusion, our study demonstrates that pendrin is located at the apical membrane of thyrocytes and that PDS gene expression is decreased in thyroid carcinomas.

Forty-four thyroid autonomously hyperfunctioning adenomas were analyzed to assess the frequency of mutations occurring in the TSH receptor (TSHR). PCR-amplified fragments encompassing the entire exon 10 of the TSHR gene were obtained from the genomic DNA extracted from the tumors and their adjacent normal tissues and were examined by direct nucleotide sequencing. Point mutations were found in 9 of the 44 adenomas examined (20%). One mutation occurred in codon 619 (Asp to Gly), four in codon 623 (three were Ala to Ser, one Ala to Val substitution), two in codon 632 (both Thr to Ile), and two in codon 633 (Asp to Tyr or His). All the alterations were located in a part of the gene coding for an area including the third intracellular loop and the sixth transmembrane domain of the TSH receptor. All mutations were somatic and heterozygotic, and none was simultaneous with alterations of ras or gsp oncogenes. Thus, our data show that in our series of 44 hyperfunctioning thyroid adenomas, a somatic mutation of the TSHR, responsible for the constitutive activation of the cAMP pathway, occurs in 20% of the tumors.

Thirty-seven thyroid autonomously hyperfunctioning adenomas were screened for mutations in the TSH receptor (TSHR), G alpha s (gsp), and ras genes. Polymerase chain reaction-amplified fragments of the TSHR C-terminal part (exon 10), the G alpha s (exons 8 and 9), and the three ras genes were obtained from the genomic DNA extracted from 37 tumors and their adjacent normal tissues and were studied by direct nucleotide sequencing and hybridization with synthetic probes. A point mutation in the third intracellular loop (codon 623) of the TSHR was found in 3 of 37 adenomas studied. This mutation codes for a change (Ala to Ser) in the TSHR structure and is somatic and heterozygotic. Constitutive activation of the TSHR was demonstrated by an increase in basal cAMP levels after transfection of Chinese hamster ovary cells with a mutated Ser623-TSHR complementary DNA. Nine gsp[00ae]MDRV[00af]- and one ras-activating mutations were also detected. No simultaneous alteration of the studied genes was present. Thus, in hyperfunctioning thyroid adenomas, our data suggest that a mutational activation of the TSHR and gsp genes may play a tumorigenic role through constitutive activation of the cAMP pathway.

To evaluate whether coexistence of Graves' disease affects the prognosis of thyroid cancer we examined the clinical and pathological characteristics of 22 differentiated thyroid carcinomas concomitant with hyperthyroidism; 13 were associated with Graves' disease, and 9 with autonomous thyroid nodules. Carcinomas were identified in a consecutive series of 359 hyperthyroid patients (132 with Graves' disease and 227 with autonomous thyroid nodules) who underwent surgery during a 6-yr period. One hundred and thirty-seven thyroid carcinomas were found in the 582 euthyroid patients operated on in the same period. In Graves' patients, carcinomas were more often multifocal (46.1% vs. 0%), locally invasive (61.5% vs. 11.1%), and metastatic to lymph nodes (61.5% vs. 11.1%) or to distant sites (23.0% vs. 0%) than in patients with autonomous thyroid nodules. In addition, carcinomas concomitant with Graves' disease were larger (3.3 +/- 1.8 vs. 1.0 +/- 0.7 cm) than the ones associated with autonomous thyroid nodules and showed a high recurrence rate. In euthyroid patients, aggressiveness of thyroid cancer was intermediate. Serum TSH levels were suppressed in all hyperthyroid patients with thyroid cancer. However, circulating thyroid-stimulating antibodies were present in 12 of 13 cancer patients with Graves' disease, but were absent in patients with autonomous thyroid nodules. Our study suggests, therefore, that TSAb may play a role in determining the high aggressiveness of thyroid cancer in Graves' disease patients and indicates that a vigorous treatment should be pursued in this subgroup of patients.

To clone and characterize antigens to autoantibodies in Hashimoto's thyroiditis we constructed a cDNA library in the expression vector lambda gt11 using mRNA prepared from Grave's thyroid tissue. This library was screened using serum from a patient with Hashimoto's thyroiditis which had an antimicrosomal antibody titer greater than 1:10(6). Five positive recombinants were identified and cloned. Of these, 3 reacted with 7 of 17 normal serum samples. The 2 other clones (IL-28 and IL-33) reacted with none of the 17 normal serum samples. IL-28 reacted with 4 of 15 and IL-33 with 2 of 15 Hashimoto's thyroiditis serum samples (antimicrosomal antibody titers, greater than 1:6400). The specificity of the interaction between the Hashimoto's thyroiditis samples and the fusion protein was demonstrated by Western blot analysis. In addition, neither 10(-6) M human thyroglobulin nor 100 mU/ml bovine TSH inhibited binding of the serum samples to these 2 clones. Lysate from clones IL-28 and IL-33 did not reduce the antimicrosomal antibody titer in a hemagglutination assay. Absorption of Hashimoto's thyroiditis serum with purified thyroid microsomes reduced the serum antimicrosomal antibody titer, but not binding to these 2 clones. The cDNA inserts of clones IL-28 and IL-33 were approximately 0.6 and 0.4 kilobases (kb), respectively. The 0.6-kb IL-28 insert was used to probe human thyroid and human liver poly(A)+ mRNA. A single band of 3.3 kb was evident only with the thyroid mRNA. The IL-28 insert was subcloned into M13 and sequenced in both directions by the dideoxy technique and found to be 572 basepairs in length. When tested against the GenBank and Dayhoff gene banks, no significant homology with any known sequence was determined. In summary, a cDNA fragment of a previously unrecognized gene coding for an autoimmune thyroid disease-related antigen has been cloned and partly characterized; and the protein produced by this clone is not thyroglobulin, the thyroid microsomal antigen, or the TSH-binding site of the TSH receptor. We have, therefore, identified a new autoimmune thyroid disease-related antigen, the pathogenetic significance of which remains to be determined.

Modifications are described in the cultured thyroid cell cAMP assay for TSH which make it suitable for the measurement of thyroid-stimulating immunoglobulins. Comparison was made between this assay and two others measuring cAMP responsiveness in human thyroid tissue, namely the thyroid slice and thyroid plasma membrane adenylate cyclase assays, all performed with the same tissue sample. Of immunoglobulin G (IgG) samples from 7 unselected patients with untreated hyperthyroidism associated with Graves' disease, 5 produced significant stimulation of cAMP content in cultured thyroid cells when compared to pooled normal IgG. None of these 7 produced a statistically significant increase in thyroid slice cAMP content when assayed in triplicate, the same replicate number used in the cultured thyroid cell assay. Similarly, none of the same Graves' IgG samples produced significant stimulation (vs. control IgG) in the membrane adenylate cyclase assay, in which sensitivity to TSH stimulation was very poor. With a scaled-down modification of the assay using microtiter wells and acetylation to enhance detection of cAMP in the RIA, significant TSI activity was observed in 15 of 18 (83%) IgG samples from patients with untreated Graves' disease. The data indicate the excellent sensitivity and precision of the thyroid cell cAMP assay, as well as its convenience.