Thyroid-stimulating hormone receptor messenger ribonucleic acid measurement in blood as a marker for circulating thyroid cancer cells and its role in the preoperative diagnosis of thyroid cancer

Detecting thyrotropin receptor mRNA from peripheral blood of patients with differentiated thyroid cancer rules out non-aggressive cases

BACKGROUND

Early diagnosis of thyroid cancer is hampered by the inability of fine-needle aspiration biopsy (FNAB) to accurately classify ∼30% of cases while preoperative cancer staging detects lymph nodal involvement in only half of cases. Liquid biopsy may present an accurate, non-invasive alternative for preoperative thyroid nodule assessment. Thyrotropin receptor (TSHR) mRNA, a surrogate marker for circulating cancer cells (CTC), may be an option for early detection of malignancy from peripheral blood, but requires methodological improvements. We aimed to investigate if TSHR mRNA can be detected in low sample volumes by employing an ultrasensitive method - droplet digital PCR (ddPCR).

METHODS

Less than 5 mL of blood was collected from 47 patients with thyroid nodules (25 benign and 22 malignant). RNA was isolated from the fraction of mononuclear cells where CTCs segregate. Samples were analysed for the presence of TSHR mRNA by ddPCR.

RESULTS

Thyrotropin receptor mRNA was detectable in 4 mL sample volumes, with the test having good specificity (80%) but modest diagnostic accuracy (68.1%). Combining TSHR mRNA with ultrasound features and FNAB diagnosis, the test reaches high rule-out performances (sensitivity = 90% and NPV = 88.2%). Strikingly, TSHR mRNA correctly classified all samples with thyroid capsule invasion, lymph node metastasis and extrathyroidal extension. If aggressiveness is defined using these parameters, TSHR mRNA test reaches 100% sensitivity and 100% NPV for detecting high-risk cases.

CONCLUSIONS

Employing ddPCR for TSHR mRNA improves its measurement by enabling detection in sample volumes common for laboratory testing. The test displays high prognostic performance, showing potential in preoperative risk assessment.

Advances in targeted therapy and biomarker research in thyroid cancer

Driven by the intricacy of the illness and the need for individualized treatments, targeted therapy and biomarker research in thyroid cancer represent an important frontier in oncology. The variety of genetic changes associated with thyroid cancer demand more investigation to elucidate molecular details. This research is clinically significant since it can be used to develop customized treatment plans. A more focused approach is provided by targeted therapies, which target certain molecular targets such as mutant BRAF or RET proteins. This strategy minimizes collateral harm to healthy tissues and may also reduce adverse effects. Simultaneously, patient categorization based on molecular profiles is made possible by biomarker exploration, which allows for customized therapy regimens and maximizes therapeutic results. The benefits of targeted therapy and biomarker research go beyond their immediate clinical impact to encompass the whole cancer landscape. Comprehending the genetic underpinnings of thyroid cancer facilitates the creation of novel treatments that specifically target aberrant molecules. This advances the treatment of thyroid cancer and advances precision medicine, paving the way for the treatment of other cancers. Taken simply, more study on thyroid cancer is promising for better patient care. The concepts discovered during this investigation have the potential to completely transform the way that care is provided, bringing in a new era of personalized, precision medicine. This paradigm shift could improve the prognosis and quality of life for individuals with thyroid cancer and act as an inspiration for advances in other cancer types.

New biomarkers: prospect for diagnosis and monitoring of thyroid disease

After the metabolic syndrome and its components, thyroid disorders represent the most common endocrine disorders, with increasing prevalence in the last two decades. Thyroid dysfunctions are distinguished by hyperthyroidism, hypothyroidism, or inflammation (thyroiditis) of the thyroid gland, in addition to the presence of thyroid nodules that can be benign or malignant. Thyroid cancer is typically detected via an ultrasound (US)-guided fine-needle aspiration biopsy (FNAB) and cytological examination of the specimen. This approach has significant limitations due to the small sample size and inability to characterize follicular lesions adequately. Due to the rapid advancement of high-throughput molecular biology techniques, it is now possible to identify new biomarkers for thyroid neoplasms that can supplement traditional imaging modalities in postoperative surveillance and aid in the preoperative cytology examination of indeterminate or follicular lesions. Here, we review current knowledge regarding biomarkers that have been reliable in detecting thyroid neoplasms, making them valuable tools for assessing the efficacy of surgical procedures or adjunctive treatment after surgery. We are particularly interested in providing an up-to-date and systematic review of emerging biomarkers, such as mRNA and non-coding RNAs, that can potentially detect thyroid neoplasms in clinical settings. We discuss evidence for miRNA, lncRNA and circRNA dysregulation in several thyroid neoplasms and assess their potential for use as diagnostic and prognostic biomarkers.

A Review of Evidence for the Involvement of the Circadian Clock Genes into Malignant Transformation of Thyroid Tissue

(1) Background: In 2013, the results of a pioneer study on abnormalities in the levels and circadian rhythmicity of expression of circadian clock genes in cancerous thyroid nodules was published. In the following years, new findings suggesting the involvement of circadian clockwork dysfunction into malignant transformation of thyroid tissue were gradually accumulating. This systematic review provides an update on existing evidence regarding the association of these genes with thyroid tumorigenesis. (2) Methods: Two bibliographic databases (Scopus and PubMed) were searched for articles from inception to 20 March 2023. The reference lists of previously published (nonsystematic) reviews were also hand-searched for additional relevant studies. (3) Results: Nine studies published between 2013 and 2022 were selected. In total, 9 of 12 tested genes were found to be either up- or downregulated. The list of such genes includes all families of core circadian clock genes that are the key components of three transcriptional-translational feedback loops of the circadian clock mechanism (BMAL1, CLOCK, NPAS2, RORα, REV-ERBα, PERs, CRYs, and DECs). (4) Conclusions: Examination of abnormalities in the levels and circadian rhythmicity of expression of circadian clock genes in thyroid tissue can help to reduce the rate of inadequate differential preoperative diagnosis for thyroid carcinoma.

Prospects of Testing Diurnal Profiles of Expressions of TSH-R and Circadian Clock Genes in Thyrocytes for Identification of Preoperative Biomarkers for Thyroid Carcinoma

Thyroid Nodules (TN) are frequent but mostly benign, and postoperative rate of benign TN attains the values from 70% to 90%. Therefore, there is an urgent need for identification of reliable preoperative diagnosis markers for patients with indeterminate thyroid cytology. In this study, an earlier unexplored design of research on preoperative biomarkers for thyroid malignancies was proposed. Evaluation of reported results of studies addressing the links of thyroid cancer to the circadian clockwork dysfunctions and abnormal activities of Thyroid-Stimulating Hormone (TSH) and its receptor (TSH-R) suggested diagnostic significance of such links. However, there is still a gap in studies of interrelationships between diurnal profiles of expression of circadian clock genes and TSH-R in indeterminate thyroid tissue exposed to different concentrations of TSH. These interrelationships might be investigated in future in vitro experiments on benign and malignant thyrocytes cultivated under normal and challenged TSH levels. Their design requires simultaneous measurement of diurnal profiles of expression of both circadian clock genes and TSH-R. Experimental results might help to bridge previous studies of preoperative biomarkers for thyroid carcinoma exploring diagnostic value of diurnal profiles of serum TSH levels, expression of TSH-R, and expression of circadian clock genes.

Circulating Biomarkers in Thyroid Cancer

Thyroid cancer is the most important endocrine cancer with increasing incidence. While thyroid cancers, especially papillary thyroid cancers, are known to exhibit generally a favorable outcome with excellent survival rates, some thyroid cancers are more aggressive with a poor prognosis. Several different biomarkers have been introduced for the diagnosis of disease, identification of tumor load, assessment of therapy response, and the detection of recurrence during follow-up of the thyroid cancer patients. This chapter gives a brief overview of the circulating biomarkers used in thyroid cancer patients.

Minimal residual disease assessment of papillary thyroid carcinoma through circulating tumor cell-based cytology

The overall estimated risk of recurrence after an apparently complete thyroid cancer resection ranges from <1% to 55%, and the high-quality pathology report is crucial for proper risk stratification. The neck ultrasound (US) and serum thyroglobulin (Tg) and anti-Tg antibody (TgAb) assays are the mainstays for Differentiated Thyroid Cancer (DTC) follow-up. However, the neck US includes a high frequency of nonspecific findings and despite the serum, Tg unmasks the presence of thyrocytes, it is not discriminating between normal and malignant cells. In this study, to improve post-surgery follow-up of minimal residual disease in papillary thyroid cancer (PTC) patients, blood-derived cytology specimens were evaluated for the presence of circulating tumor cells (CTCs). The presence of CTCs of thyroid origin was confirmed by cytomorphological and tissue-specific antigens analysis (Thyroid Transcription Factor-1/TTF-1 and Tg) and proliferative profile (percentage of cells in S-phase). Our data revealed an unfavorable' prognostic risk in patients with >5% CTCs (p = 0.09) and with >30% S-phase cells at baseline (p = 0.0015), predicting ≤1 year relapsing lesion event. These results suggest a new intriguing frontier of precision oncology forefront cytology-based liquid biopsy.

Opportunities and Challenges of Liquid Biopsy in Thyroid Cancer

Thyroid cancer is the most common malignancy of the endocrine system, encompassing different entities with distinct histological features and clinical behavior. The diagnostic definition, therapeutic approach, and follow-up of thyroid cancers display some controversial aspects that represent unmet medical needs. Liquid biopsy is a non-invasive approach that detects and analyzes biological samples released from the tumor into the bloodstream. With the use of different technologies, tumor cells, free nucleic acids, and extracellular vesicles can be retrieved in the serum of cancer patients and valuable molecular information can be obtained. Recently, a growing body of evidence is accumulating concerning the use of liquid biopsy in thyroid cancer, as it can be exploited to define a patient's diagnosis, estimate their prognosis, and monitor tumor recurrence or treatment response. Indeed, liquid biopsy can be a valuable tool to overcome the limits of conventional management of thyroid malignancies. In this review, we summarize currently available data about liquid biopsy in differentiated, poorly differentiated/anaplastic, and medullary thyroid cancer, focusing on circulating tumor cells, circulating free nucleic acids, and extracellular vesicles.

Liquid biopsy in thyroid cancer: from circulating biomarkers to a new prospective of tumor monitoring and therapy

Recently, liquid biopsy has attracted much interest as a tool for early cancer screening, prognosis, monitoring and response to treatment in many different cancer types. Indeed, liquid biopsies can be repeatedly performed in a noninvasive way, at lower cost and without the risks associated to the classic tissue biopsy. The objective of this monography was to describe the main components studied in liquid biopsy (circulating tumor nucleic acids, circulating tumor cells and extracellular vesicles) and how they have been explored in thyroid cancer, through an in-depth scientific literature review. While circulating tumor cells are the most represented component in the literature of liquid biopsy in thyroid cancer, circulating tumor nucleic acids and extracellular vesicles have also been recently explored. One important challenge in this field of research, especially for differentiated thyroid cancer, has been the low quantity of circulating components with respect to other cancer types, requiring more advanced techniques for both isolation and analysis. Despite these limitations, liquid biopsy showed promise as an additional noninvasive tool for diagnosis, prognosis, to predict outcome and therapeutic response in differentiated, medullary and anaplastic thyroid cancer.

An overall and dose-response meta-analysis for thyrotropin and thyroid cancer risk by histological type

Thyrotropin (TSH) is thought as a risk factor for thyroid cancer. However, the effect of serum TSH might depend on histological types of thyroid cancer. We searched for related studies including serum TSH as an exposure and thyroid cancer as a result in PUBMED, EMBASE and Chinese National Knowledge Infrastructure up to April 21, 2016. This meta-analysis included 22 articles with 53,538 participants. When comparing all histological thyroid cancer, the pooled odds ratios of thyroid cancer in patients with nodules was found to increase significantly with higher serum TSH concentrations for differentiated thyroid carcinoma (1.88 vs .1.48, P = 0.0000) and papillary thyroid carcinoma (2.08 vs. 1.48, P = 0.0006). Each 1 mU/L increase of serum TSH was associated with 14% greater risk of thyroid cancer for all histological thyroid cancer, 16% for differentiated thyroid carcinoma and 22% for papillary thyroid carcinoma. In addition, high serum TSH was associated with a reduced risk for follicular thyroid carcinoma (OR = 0.73, 95% CI: 0.52, 1.02). This meta-analysis suggested high serum TSH concentration is risky for papillary thyroid carcinoma but not for follicular thyroid carcinoma.

Circulating thyroid stimulating hormone receptor messenger RNA and differentiated thyroid cancer: A diagnostic meta-analysis

Thyroid stimulating hormone receptor messenger RNA (TSHR-mRNA) is over-expressed in thyroid cancer patients, which indicates that TSHR-mRNA is a potential biomarker of thyroid cancer. However, system evaluation for TSHR-mRNA as a diagnostic biomarker of thyroid cancer is deficient. The performance of TSHR-mRNA for thyroid cancer diagnosis was evaluated in this study. Three common international databases as well as a Chinese database were applied for literature researching. Quality assessment of the included literatures was conducted by the QUADAS-2 tool. Totally, 1027 patients from nine studies eligible for the meta-analysis were included in this study. Global sensitivity and specificity for the positivity of TSHR-mRNA in the thyroid cancer diagnosis is 72% and 82%. The value of AUC for this test performance was 0.84. Our meta-analysis suggests that TSHR-mRNA might be a potential biomarker to complete present diagnostic methods for early and precision diagnosis of thyroid cancer. Notably, this findings need validation thorough large-scale clinical studies.

Circulating thyroid cancer biomarkers: Current limitations and future prospects

Differentiated thyroid cancer (DTC) is the most common malignancy of the endocrine system. There has been a significant increase in its incidence over the past two decades attributable mainly to the use of more sensitive diagnostic modalities. Ultrasound-guided fine needle aspiration cytology is the mainstay of diagnosis of benign disorders and malignancy. However, approximately 20% of lesions cannot be adequately categorized as benign or malignant. In the postoperative setting, monitoring of thyroglobulin (Tg) levels has been employed for the detection of disease recurrence. Unfortunately, Tg antibodies are common and interfere with Tg measurement in this subset of patients. Despite this limitation, Tg remains the sole widely used thyroid cancer biomarker in the clinical setting. In an attempt to bypass antibody interference, research has focused mainly on mRNA targets thought to be exclusively expressed in thyroid cells. Tg and thyroid stimulating hormone receptor (TSHR) mRNA have been extensively studied both for discerning between benign disease and malignancy and in postoperative disease surveillance. However, results among reports have been inconsistent probably reflecting considerable differences in methodology. Recently, microRNA (miRNA) targets are being investigated as potential biomarkers in DTC. MiRNAs are more stable molecules and theoretically are not as vulnerable as mRNA during manipulation. Initial results have been encouraging but large-scale studies are warranted to verify and elucidate their potential application in diagnosis and postoperative surveillance of thyroid cancer. Several other novel targets, primarily mutations and circulating cells, are currently emerging as promising thyroid cancer circulating biomarkers. Although interesting and intriguing, data are limited and derive from small-scale studies in specific patient cohorts. Further research findings demonstrating their value are awaited with anticipation.

Comparative analysis of diagnostic performance, feasibility and cost of different test-methods for thyroid nodules with indeterminate cytology

Since it is impossible to recognize malignancy at fine needle aspiration (FNA) cytology in indeterminate thyroid nodules, surgery is recommended for all of them. However, cancer rate at final histology is <30%. Many different test-methods have been proposed to increase diagnostic accuracy in such lesions, including Galectin-3-ICC (GAL-3-ICC), BRAF mutation analysis (BRAF), Gene Expression Classifier (GEC) alone and GEC+BRAF, mutation/fusion (M/F) panel, alone, M/F panel+miRNA GEC, and M/F panel by next generation sequencing (NGS), FDG-PET/CT, MIBI-Scan and TSHR mRNA blood assay.We performed systematic reviews and meta-analyses to compare their features, feasibility, diagnostic performance and cost. GEC, GEC+BRAF, M/F panel+miRNA GEC and M/F panel by NGS were the best in ruling-out malignancy (sensitivity = 90%, 89%, 89% and 90% respectively). BRAF and M/F panel alone and by NGS were the best in ruling-in malignancy (specificity = 100%, 93% and 93%). The M/F by NGS showed the highest accuracy (92%) and BRAF the highest diagnostic odds ratio (DOR) (247). GAL-3-ICC performed well as rule-out (sensitivity = 83%) and rule-in test (specificity = 85%), with good accuracy (84%) and high DOR (27) and is one of the cheapest (113 USD) and easiest one to be performed in different clinical settings.In conclusion, the more accurate molecular-based test-methods are still expensive and restricted to few, highly specialized and centralized laboratories. GAL-3-ICC, although limited by some false negatives, represents the most suitable screening test-method to be applied on a large-scale basis in the diagnostic algorithm of indeterminate thyroid lesions.

Circulating tumor cells in thyroid carcinoma - the prognostic role of this biomarker. Review of the literature

Thyroid cancer is a disease with a good prognosis and high survival rates, but having a marked growth of incidence all over the world in the last years. This fact requires special attention of researchers for understanding the behavior of this disease and to establish a correct therapy. Analysis of circulating tumor cells in patients with different malignancies is nowadays a new and exciting research tool, which can improve the diagnosis and prevent the metastatic disease. In the case of thyroid carcinoma there are few studies which explore these biomarkers and investigate the prognostic significance of circulating tumor cells. With this review we seek to emphasize the role of these cells to better understand the mechanisms of invasion or metastasis and to establish a new research base to treat aggressive forms of this type of cancer. Most of the included studies demonstrate the efficacy of these markers for diagnosis and follow up.

Correlation of thyroid stimulating hormone receptor mRNA expression levels in peripheral blood with undesirable clinicopathological features in papillary thyroid carcinoma patients

To determine the extent to which thyroid stimulating hormone receptor (TSHR) mRNA in peripheral blood (PB) has diagnostic value for papillary thyroid carcinoma (PTC). We obtained pre- and postoperative PB samples from 104 thyroid disease patients and collected 11 healthy volunteers' PB samples twice apiece at different times. We used reverse transcription polymerase chain reaction (RT-PCR) to quantify TSHR mRNA expression levels in the samples. T-test and chi-square test were used to compare quantitative data and rates. The mean preoperative PB TSHR mRNA expression level of the PTC patients was significantly higher than that of the healthy volunteers. However, on the postoperative day 1, PB TSHR mRNA level of PTC patients significantly decreased but not for healthy controls. Preoperative PB TSHR mRNA expression levels were significantly associated with patient age, capsular invasion status, lymph node metastasis status, and BRAF^V600E mutation status (P < 0.05) but not gender, tumor size, number of cancer foci, or Hashimoto thyroiditis status. Preoperative assessment of the PB TSHR mRNA expression level combined with ultrasonography of the thyroid had better accuracy in the diagnosis of PTC than either method alone did. Moreover, TSHR mRNA expression significantly affected recurrence of PTC patients. Our findings suggest that PB TSHR mRNA expression level is a promising novel biomarker for the early detection, diagnosis, and treatment of PTC. It may serve as a noninvasive means of PTC detection and a prognostic biomarker of residual tumor and help guide further treatment.

Combined analysis of circulating epithelial cells and serum thyroglobulin for distinguishing disease status of the patients with papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) accounts for about 80% of the cases in thyroid cancer. Routine surveillance by serum thyroglobulin (Tg) and medical imaging is the current practice to monitor disease progression of the patients. Whether enumeration of circulating epithelial cells (CECs) helps to define disease status of PTC patients was investigated. CECs were enriched from the peripheral blood of the healthy control subjects (G1, n = 17) and the patients at disease-free status (G2, n = 26) or with distant metastasis (G3, n = 22). The number of CECs expressing epithelial cell adhesion molecule (EpCAM) or thyroid-stimulating hormone receptor (TSHR) was determined by immunofluorescence microscopy analyses. The medium number of EpCAM+-CECs was 6 (interquartile range 1-11), 12 (interquartile range 7-16) and 91 (interquartile range 31-206) cells/ml of blood for G1, G2 and G3, respectively. EpCAM+-CEC counts were significantly higher in G3 than in G1 (p < 0.05) and G2 (p < 0.05). The medium number of TSHR+-CECs was 9 (interquartile range 3-13), 16 (interquartile range 10-24) and 100 (interquartile range 31-226) cells/ml of blood for G1, G2 and G3, respectively. The TSHR+-CEC counts also distinguished G3 from G1 (p < 0.05) and G2 (p < 0.05). With an appropriate cut off value of CEC count, the disease status for 97.9% (47/48) of the cases was clearly defined. Notably, the metastatic disease for all patients in G3 (22/22) was revealed by combined analysis of serum Tg and CEC. This study implicates that CEC testing can supplement the current standard methods for monitoring disease status of PTC.

Engineering Multi-Walled Carbon Nanotube Therapeutic Bionanofluids to Selectively Target Papillary Thyroid Cancer Cells

BACKGROUND

The incidence of papillary thyroid carcinoma (PTC) has risen steadily over the past few decades as well as the recurrence rates. It has been proposed that targeted ablative physical therapy could be a therapeutic modality in thyroid cancer. Targeted bio-affinity functionalized multi-walled carbon nanotubes (BioNanofluid) act locally, to efficiently convert external light energy to heat thereby specifically killing cancer cells. This may represent a promising new cancer therapeutic modality, advancing beyond conventional laser ablation and other nanoparticle approaches.

METHODS

Thyroid Stimulating Hormone Receptor (TSHR) was selected as a target for PTC cells, due to its wide expression. Either TSHR antibodies or Thyrogen or purified TSH (Thyrotropin) were chemically conjugated to our functionalized Bionanofluid. A diode laser system (532 nm) was used to illuminate a PTC cell line for set exposure times. Cell death was assessed using Trypan Blue staining.

RESULTS

TSHR-targeted BioNanofluids were capable of selectively ablating BCPAP, a TSHR-positive PTC cell line, while not TSHR-null NSC-34 cells. We determined that a 2:1 BCPAP cell:α-TSHR-BioNanofluid conjugate ratio and a 30 second laser exposure killed approximately 60% of the BCPAP cells, while 65% and >70% of cells were ablated using Thyrotropin- and Thyrogen-BioNanofluid conjugates, respectively. Furthermore, minimal non-targeted killing was observed using selective controls.

CONCLUSION

A BioNanofluid platform offering a potential therapeutic path for papillary thyroid cancer has been investigated, with our in vitro results suggesting the development of a potent and rapid method of selective cancer cell killing. Therefore, BioNanofluid treatment emphasizes the need for new technology to treat patients with local recurrence and metastatic disease who are currently undergoing either re-operative neck explorations, repeated administration of radioactive iodine and as a last resort external beam radiation or chemotherapy, with fewer side effects and improved quality of life.

Evaluation and management of thyroid nodules with atypia/follicular lesion of undetermined significance on fine-needle aspiration

Since the introduction of the Bethesda System for Reporting Thyroid Cytopathology in 2008, the management of thyroid nodules has become more standardized, with clearly defined algorithms based on risk of malignancy for each of the six cytologic categories. However, the management of a thyroid nodule with a fine-needle aspiration biopsy classified as Bethesda III, or atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), remains controversial due to the cytologic heterogeneity and the variability in the reported rates of malignancy. In this review, the history and rationale for the new Bethesda III category is examined, the reported incidence and risk of malignancy from published studies is reviewed and recommendations for management of patients with a thyroid nodule and AUS/FLUS are provided. Recent advances in molecular analysis and their role in the evaluation of patients with AUS/FLUS are also discussed.

CIRCULATING THYROID-STIMULATING HORMONE RECEPTOR MESSENGER RNA AS A MARKER OF TUMOR AGGRESSIVENESS IN PATIENTS WITH PAPILLARY THYROID MICROCARCINOMA

BACKGROUND

We have previously shown that thyroid-stimulating hormone receptor messenger RNA (TSHR mRNA) is detectable in the peripheral blood of patients with papillary thyroid microcarcinoma (PTmC). The aim of this study was to analyze the utility of TSHR mRNA status as a marker of tumor aggressiveness in patients with PTmC.

METHODS

Preoperative TSHR mRNA values were obtained in 152 patients who underwent thyroidectomy and were found to have PTmC on final pathology. Clinical parameters were analyzed from an institutional review board-approved database using χ(2) and t tests.

RESULTS

Preoperatively, TSHR mRNA was detected in the peripheral blood in 46% of patients, which was less than that for macroscopic papillary thyroid carcinoma (PTC) (80%) but higher than for benign thyroid disease (18%) (P<.001). The focus of cancer was larger in the TSHR mRNA-positive group compared to the negative group (0.41 vs. 0.30 cm, respectively, P = .015). The prevalence of tall-cell variant was higher in the TSHR mRNA positive group. The rates of lymph node (LN) metastasis (16% vs. 10%), multifocality (46% vs. 49%), and extra-thyroidal extension (10% vs. 5%) were similar between the TSHR mRNA-positive and-negative groups, respectively. In patients 45 years or older, rate of LN metastasis was higher in those who were TSHR mRNA positive (10%) versus negative (2%) (P = .039). TSHR mRNA positivity predicted a higher likelihood of radioactive iodine treatment (36% vs. 17%, P = .009) postoperatively.

CONCLUSION

This study shows that TSHR mRNA, which is a marker of circulating thyroid cancer cells, is detectable in about half of patients with PTmC. The positivity of this marker predicts a higher likelihood of LN involvement in patients with PTmC who are 45 years or older.

Molecular markers for thyroid cancer diagnosis, prognosis, and targeted therapy

Molecular markers including gene expression profiles, somatic gene alterations, and circulating peripheral markers have augmented diagnostic, prognostic, and therapeutic options for thyroid cancer patients.

Role of molecular diagnostic markers in the management of indeterminate and suspicious thyroid nodules

Incidental thyroid nodules are commonly found during routine neck examination. Fine needle aspiration (FNA) followed by cytological examination is currently considered as the most reliable method for evaluation of thyroid nodules. However, 10–40% of FNA results are inconclusive, and are reported as indeterminate or suspicious. Approximately 20% of indeterminate or suspicious nodules are malignant. Therefore, there has been an increasing trend in use of molecular markers as an adjunctive measure for more accurate preoperative diagnosis of indeterminate or suspicious nodules. Molecular markers can be used alone or as a part of molecular panels. Although some investigations revealed promising findings regarding the potential use of molecular markers in the management of thyroid nodules, their true impact on management of patients with indeterminate nodules is still unclear.

Molecular diagnostics for thyroid nodules: the current state of affairs

Molecular diagnostics offers great promise for the evaluation of cytologically indeterminate thyroid nodules. Numerous molecular genetic and immunohistochemical tests have been developed that may be performed on thyroid specimens obtained during standard fine-needle aspiration, some of which may greatly improve diagnostic yield. A sound understanding of the diagnostic performance of these tests, and how they can enhance clinical practice, is important. This article reviews the diagnostic utility of immunohistochemical and molecular testing for the clinical assessment of thyroid nodules, and makes recommendations about how these tests can be integrated into clinical practice for patients with cytologically indeterminate thyroid nodules.

Molecular markers in thyroid cytology: diagnostic and prognostic implications

The discovery of thyroid nodules in the general population has risen markedly with the greater use of ultrasound resulting in increasing use of ultrasound-guided fine needle aspiration (FNA) biopsy. Although FNA can identify the majority of nodules as either benign or malignant, one-third of aspirates demonstrate indeterminate cytologic characteristics. Though most of these nodules will be pathologically benign, thyroid surgery has usually been needed to make an accurate diagnosis, and the extent of surgery needed (lobectomy versus total thyroidectomy) is difficult to predict in advance. New molecular techniques are being investigated and used clinically to improve decision making in patients with thyroid nodules with indeterminate cytology. These molecular markers have the potential to help clinicians decide which patients may be monitored without thyroid surgery, and also the optimal strategy when surgery is felt to be necessary.

Optimization of a high-throughput whole blood expression profiling methodology and its application to assess the pharmacodynamics of interferon (IFN) beta-1a or polyethylene glycol-conjugated IFN beta-1a in healthy clinical trial subjects

Background

Clinical trials offer a unique opportunity to study human disease and response to therapy in a highly controlled setting. The application of high-throughput expression profiling to peripheral blood from clinical trial subjects could facilitate the identification of transcripts that function as prognostic or diagnostic markers of disease or treatment. The paramount issue for these methods is the ability to produce robust, reproducible, and timely mRNA expression profiles from peripheral blood. Single-stranded complementary DNA (sscDNA) targets derived from whole blood exhibit improved detection of transcripts and reduced variance as compared to their complementary RNA counterparts and therefore provide a better option for interrogation of peripheral blood on oligonucleotide arrays. High-throughput microarray technologies such as the high-throughput plate array platform offer several advantages compared with slide- or cartridge-based arrays; however, manufacturer’s protocols do not support the use of sscDNA targets.

Results

We have developed a highly reproducible, high-through put, whole blood expression profiling methodology based on sscDNA and used it to analyze human brain reference RNA and universal human reference RNA samples to identify experimental conditions that most highly correlated with a gold standard quantitative polymerase chain reaction reference dataset. We then utilized the optimized method to analyze whole blood samples from healthy clinical trial subjects treated with different versions of interferon (IFN) beta-1a. Analysis of whole blood samples before and after treatment with intramuscular [IM] IFN beta-1a or polyethylene glycol-conjugated IFN (PEG-IFN) beta-1a under optimized experimental conditions demonstrated that PEG-IFN beta-1a induced a more sustained and prolonged pharmacodynamic response than unmodified IM IFN beta-1a. These results provide validation of the utility of this new methodology and suggest the potential therapeutic benefit of a sustained pharmacodynamic response to PEG-IFN beta-1a.

Conclusions

This novel microarray methodology is ideally suited for utilization in large clinical studies to identify expressed transcripts for the elucidation of disease mechanisms of action and as prognostic, diagnostic, or toxicity markers.

Overview of molecular biomarkers for enhancing the management of cytologically indeterminate thyroid nodules and thyroid cancer

OBJECTIVE

To provide information on molecular biomarkers that can help assess cytologically indeterminate thyroid nodules.

METHODS

Published studies on immunohistologic, somatic mutation, gene expression classifier, microRNA, and thyrotropin receptor messenger RNA biomarkers are reviewed, and commercially available molecular test panels are described.

RESULTS

Thyroid nodules are common, and clinical guidelines delineate an algorithmic approach including serum thyroid-stimulating hormone measurement, diagnostic ultrasound examination, and, when appropriate, fine-needle aspiration (FNA) biopsy for determination of a benign versus malignant status. In clinical practice, approximately 20% of FNA-derived cytology reports are classified as "indeterminate" or follicular nodules that do not fulfill either benign or malignant criteria. In this setting, the actual risk for malignancy of a cytologically indeterminate nodule ranges from approximately 15% to 34%. Research describing molecular biomarkers from thyroid cancer tissue has been applied to FNA-derived thyroid nodule material. There is also a serum molecular marker that has been reported with goals similar to those for the FNA-derived molecular markers: to enhance the preoperative diagnosis of thyroid cancer and reduce the large number of patients who have a diagnostic surgical procedure for benign thyroid nodules.

CONCLUSION

Progress toward the foregoing goals has been made and continues to evolve with the recent appearance of molecular biomarker tests that can be selectively applied for further assessment of cytologically indeterminate thyroid nodules.

Promise and pitfalls of molecular markers of thyroid nodules

Thyroid nodules are common in the general population with a prevalence of 5-7% The initial evaluation of thyroid nodules commonly involves thyroid function tests, an ultrasound (USG) and fine needle aspiration biopsy (FNAB). The optimal management of patients with thyroid nodules with indeterminate cytology is plagued by the lack of highly sensitive and specific diagnostic modalities In this article we attempt to review the available literature on the molecular markers which are increasingly being studied for their diagnostic utility in assessing thyroid nodules. The various molecular markers consist of gene mutations, gene re arrangements, RNA based assays and immunohistochemical markers. The molecular markers definitely would help to optimise the management of such patients.

The quest for diagnostic molecular markers for thyroid nodules with indeterminate or suspicious cytology

Thyroid nodules are very common and fine needle aspiration (FNA) is a very sensitive means of diagnosis. However, its limitations include the fact that the cytology reports are often indeterminate or suspicious only. The quest for adjunctive measures to improve its specificity has been ongoing for decades, but significant results have remained elusive. The potential use of diagnostic molecular markers appears to be the most promising area of research at this time.

Advances in the follow-up of differentiated or medullary thyroid cancer

The long-term survival of patients with thyroid cancer and the possibility of tumour recurrence up to 30-40 years after the achievement of a disease-free status illustrate the importance of lifelong follow-up in these individuals. This Review discusses the most innovative aspects of follow-up protocols for patients with differentiated thyroid cancer, that is, of papillary or follicular hystotype, and those with medullary thyroid cancer. Particular focus is placed on the relevance of new ultrasensitive assays for thyroglobulin measurement and the option of using recombinant human TSH to stimulate thyroglobulin secretion. Methods to compensate for the loss of diagnostic significance of serum thyroglobulin levels in patients with differentiated thyroid cancer and circulating anti-thyroglobulin antibodies are highlighted, as well as the role of the postoperative calcitonin stimulation test and the clinical relevance of determining the doubling time of calcitonin and carcinoembryonic antigen in patients with medullary thyroid cancer. Moreover, this Review gives some insights into the role of molecular thyroid cancer testing, both for prognostic and for therapeutic purposes. Finally, a general overview of traditional imaging procedures, such as neck ultrasonography, CT, MRI and bone scintigraphy, is provided alongside a comparison with new nuclear imaging tests such as PET.

Blood presence of circulating oncofetal fibronectin mRNA, by RT-PCR, does not represent a useful specific marker for the management and follow-up of thyroid cancer patients

BACKGROUND

Recent studies strongly suggest the use of oncofetal fibronectin (onfFN) mRNA in diagnostic follow-up and staging due to its very high specificity for thyroid cancers. Since the use of this marker has not been well established yet, particularly in the monitoring of minimal residual disease, we have tried to verify the diagnostic power of onfFN and its usefulness as a prognostic molecular marker. For this reason, we evaluated (by RT-PCR) the presence of onfFN mRNAs, not only in blood samples and thyroid tissues (both normal and neoplastic), but also in different biological fluids (such as K3-EDTA blood samples, saliva and urine) belonging to healthy individuals.

METHODS

Molecular investigations, such as RT-PCR protocol, and sequencing of onfFN cDNAs evaluation of the above-mentioned samples were performed.

RESULTS

The onfFN transcript was largely expressed in all benign and malignant thyroid tissues [differentiated thyroid carcinomas (DTCs)] tested as well as in a large number of biological fluids; in particular, 100% urine samples were positive for onfFN transcript as compared to the thyroglobulin (Tg) mRNA (75%), while saliva was always positive for onfFN and never for Tg. These findings indicate that onfFN cannot be considered a marker specific for thyroid cancer presence. Finally, Tg results were positive in a large part of the samples, but not always in concomitance with onfFN.

CONCLUSIONS

We underline how the complexity of onfFN transcripts could affect the RT-PCR procedure. In addition, the presence of onfFN transcripts in several normal and cancer tissues, along with non-thyroid biological fluids or cells, does not allow the use of this marker for cancer monitoring.

Circulating thyrotropin receptor messenger RNA for evaluation of thyroid nodules and surveillance of thyroid cancer in children

PURPOSE

The aim of this study was to determine the role of thyrotropin receptor messenger RNA as a novel blood test for evaluation of thyroid nodules and cancer in children.

METHODS

We reviewed thyroid disease management of patients younger than 18 years with thyrotropin receptor messenger RNA measurements identified from a prospective, institutional review board-approved registry during 2008 to 2010.

RESULTS

Thirty-nine thyrotropin receptor messenger RNA measurements were made in 21 female patients (12-17 years old; median, 16 years). Four patients with fine-needle aspiration only had benign thyroid cytology, and 3 of 4 had undetectable thyrotropin receptor messenger RNA. Seventeen patients underwent 22 thyroid operations. Preoperative thyrotropin receptor messenger RNA was measured in 9 patients: 3 of 4 with thyroid cancer had elevated levels and 3 of 5 with goiters undetectable. Postthyroidectomy surveillance (median, 16 months; range, 6-24) of 11 thyroid cancer patients (8 papillary, 3 follicular) showed that thyrotropin receptor messenger RNA was concordant with thyroglobulin in 14 (73%) of 19 measurements. In 3 (16%) of 19 measurements, thyrotropin receptor messenger RNA was the only blood test useful for disease assessment because of elevated antithyroglobulin antibodies. Overall, to predict thyroid cancer, thyrotropin receptor messenger RNA demonstrated 73% sensitivity, 82% specificity, 62% positive predictive value, 88% negative predictive value, and 79% accuracy.

CONCLUSION

Thyrotropin receptor messenger RNA provides complementary evaluation to thyroglobulin and fine-needle aspiration for pediatric thyroid nodule management.

An elevated level of TSH might be predictive of differentiated thyroid cancer

Suppression therapy of thyreostimulin (TSH) using thyroid hormones improves survival of subjects operated for differentiated thyroid cancer. The TSH level might be different depending on the type of nodule. The objective of this study was to compare retrospectively the TSH level between two groups of subjects who underwent total thyroidectomy for a nodule, matched on sex, ethnicity, age and biological method of TSH measurement, one whose final histology was benign and one malignant. There was no significant difference between the two groups in terms of age, sex, family history of thyroid disease or thyroid autoimmunity. The subjects, whose final histology was malignant, had a mean TSH level significantly higher than subjects with benign disease (1.55 mU/l versus 0.96 mU/l, P=0.003). Cancer risk was greater when the TSH was in the upper tertile of normal range. There was no correlation between the risk of thyroid cancer and age, sex, family history of thyroid disease, or menopausal status. The relative risk of having thyroid carcinoma was higher when the margins of nodules were blurred or in the presence of microcalcifications. These data confirm a trend toward baseline values of TSH higher in subjects with a thyroid-differentiated cancer. However, we could not define a preoperative threshold that would reliably determine the malignant or benign nature of the nodule.

Recovering circulating extracellular or cell-free RNA from bodily fluids

The presence of extracellular circulating or cell-free RNA in biological fluids is becoming a promising diagnostic tool for non invasive and cost effective cancer detection. Extracellular RNA or miRNA as biological marker could be used either for the early detection and diagnosis of the disease or as a marker of recurrence patterns and surveillance. In this review article, we refer to the origin of the circulating extracellular RNA, we summarise the data on the biological fluids (serum/plasma, saliva, urine, cerebrospinal fluid and bronchial lavage fluid) of patients suffering from various types of malignancies reported to contain a substantial amount of circulating extracellular (or cell-free) RNAs and we discuss the appropriate reagents and methodologies needed to be employed in order to obtain RNA material of high quality and integrity for the majority of the experimental methods used in RNA expression analysis. Furthermore, we discuss the advantages and disadvantages of the RT-PCR or microarray methodology which are the methods more often employed in procedures of extracellular RNA analysis.

Blood thyroglobulin and TSH receptor mRNA detection by RT-PCR in the follow-up of differentiated thyroid cancer patients

OBJECTIVE

During the last years several groups have used the technique of RT-PCR for the detection of circulating thyroid cells, through the amplification of thyroglobulin (Tg) and TSH receptor(TSH-R) mRNA; however the published results are controversial. In this study we investigated the utility for the detection of Tg and TSH-R mRNA by RT-PCR in patients with differentiated thyroid cancer (DTC) during treatment with levothyroxine.

SUBJECTS AND METHODS

We investigated the expression of Tg and TSH-R mRNA by single and nested RT-PCR in the blood of 3 groups of subjects: (A) 34 patients with DTC and no evidence of disease, (B) 8 patients with DTC and evidence of local or distant metastasis and (C) 13 normal subjects. Expression levels of Tg mRNA were also analysed by comparative semi-quantitative RT-PCR.

RESULTS

Tg and TSH-R mRNA signals were detected in all subjects (patients with DTC with and without evidence of disease and in normal subjects) by single or nested RT-PCR. By semi-quantitative RT-PCR and densitometric analysis of PCR products, mean levels of circulating Tg mRNA of the 3 groups were: Group A 0.182+/-0.107, Group B 0.329+/-0.298 and Group C 0.305+/-0.217.

CONCLUSIONS

Single or nested RT-PCR for Tg and TSH-R mRNA is not a suitable tool in the follow-up of patients with DTC. Lower levels of Tg mRNA in patients with DTC without evidence of disease, although not significant, may indicate that small numbers of thyroid cells may be normally present in the circulation or may represent an ectopic transcription of messengers from blood cells.

Oncofetal fibronectin mRNA is highly abundant in the blood of patients with papillary thyroid carcinoma and correlates with high-serum thyroid-stimulating hormone levels

BACKGROUND

Papillary thyroid carcinoma (PTC) cells express oncofetal fibronectin (onfFN) mRNA, which may be useful to detect circulating tumor cells. The objective of this study was to determine the fraction of PTC patients having onfFN mRNA in their peripheral blood and to determine if onfFN mRNA levels are correlated with the status of the disease or with thyroid-stimulating hormone (TSH) serum concentrations.

METHODS

This study included 95 PTC patients, who were previously treated by thyroidectomy and radioactive iodine administration. Patients were examined by cervical sonography, whole-body (131)I scintigraphy, thyroglobulin measurement, and onfFN mRNA quantification both when they were being treated with L-thyroxine (L-T4) and after L-T4 withdrawal. The mean value for onfFN mRNA in blood from 25 healthy subjects was used as control for the onfFN mRNA assay.

RESULTS

After L-T4 withdrawal, serum TSH levels rose and onfFN mRNA was found in the peripheral blood of 33 of 64 (52%) disease-free patients, 15 of 23 (65%) patients with local residual disease, and 6 of 8 (75%) patients with known local or distant metastases. Continuous administration of L-T4 repressed serum TSH. In this state none of 17 (0%) disease-free patients and 1 of 4 (25%) patients with local residual disease had an elevated onfFN mRNA level, and 2 of 4 (50%) patients with metastasis had positive tests for serum onfFN mRNA.

CONCLUSIONS

onfFN transcripts are highly abundant in the peripheral blood of patients with PTC. L-T4 withdrawal, which produced elevated serum TSH concentrations in these athyroidic patients, markedly increased the fraction with positive tests for serum onfFN mRNA at all stages of the disease. Analyzing onfFN mRNA in the absence of a TSH stimulus allows a much better discrimination of different states of PTC disease and, based on current concepts of the significance of circulating mRNA, may be a useful tool to detect circulating thyroid cancer cells.

Hormones as biomarkers: practical guide to utilizing luminex technologies for biomarker research

Hormones are chemical messengers produced in one part of the body and released into the blood to trigger or regulate particular functions of the body in another part. Hormone actions vary widely, but can include stimulation or inhibition of growth, induction or suppression of apoptosis, activation or inhibition of the immune system, regulating metabolism, and preparation for a new activity or phase of life. There is a growing interest in the role that hormones may play in the development and progression of various cancers. Recent research suggests that hormone levels may explain differences in risk for some of the most commonly diagnosed cancers, including breast, ovarian, and others; however, additional studies utilizing novel hormone measurement technologies are needed to investigate the roles of common hormones in cancer. Increasing our understanding of the role of hormones and other biomarkers in the etiology and the course of different cancers has a great potential to facilitate the development of new treatment modalities. This chapter provides an overview on multiplexing xMAP technology by Luminex (Austin, TX) that can be used for simultaneous analysis of several biologic markers, e.g., hormones. The xMAP immunoassay technology combines the principle of a sandwich ELISA with the fluorescent-bead-based technology allowing individual and multiplex analysis of up to 100 different analytes in a single microtiter well. Serum assay described in the methods section is performed in 96-well microplate format according to the protocol provided by LINCO Research, Inc. (St. Louis, MO). Human Pituitary LINCOplex Kit is utilized for simultaneous quantification of six pituitary hormones in serum, plasma, tissue lysate, and culture supernatant samples: Prolactin, FSH, LH, TSH, GH, and ACTH.

Recent developments in predicting thyroid malignancy

PURPOSE OF REVIEW

To provide an update on potential predictors of thyroid malignancy and how their use may alter clinical management.

RECENT FINDINGS

As thyroid nodules become more prevalent clinicians are increasingly impelled to identify the optimal predictor(s) of thyroid malignancy, with the goal of guiding management based on assessed risk. The gold standard evaluation for thyroid nodules is ultrasound-guided fine-needle aspiration biopsy. Fine-needle aspiration biopsy is not perfect and adjuncts which complement its predictive value are being investigated from several innovative perspectives. These include large tumor size (> or =4 cm), which appears to be an independent predictor of thyroid malignancy; 18F-fluorodeoxyglucose positron emission tomography, which appears to facilitate exclusion of malignancy in cytologically indeterminate thyroid nodules; and peripheral blood and fine-needle aspiration biopsy analysis of molecular markers, which may help to identify malignant thyroid nodules with greater specificity.

SUMMARY

Fine-needle aspiration biopsy of large thyroid nodules has a high false-negative rate and should be considered for diagnostic lobectomy. Nodule size appears to be an independent factor predicting malignancy and indeterminate lesions at least 4 cm should be considered for initial total thyroidectomy. Nuclear imaging may aid exclusion of malignancy in thyroid nodules and molecular markers have great promise in predicting thyroid malignancy with higher specificity.

TSH signalling and cancer

Thyroid cancers are the most frequent endocrine neoplasms and mutations in the thyrotropin receptor (TSHR) are unusually frequent. Here we present the state-of-the-art concerning the role of TSHR in thyroid cancer and discuss it in light of the cancer stem cell theory or the classical view. We briefly review the gene and protein structure updating the cancer related TSHR mutations database. Intriguingly, hyperfunctioning TSHR mutants characterise differentiated cancers in contrast to undifferentiated thyroid cancers which very often bear silenced TSHR. It remains unclear whether TSHR alterations in thyroid cancers play a role in the onset or they appear as a consequence of genetic instability during evolution, but the presence of functional TSHR is exploited in therapy. We outline the signalling network build up in the thyrocyte between TSHR/PKA and other proliferative pathways such as Wnt, PI3K and MAPK. This networks integrity surely plays a role in the onset/evolution of thyroid cancer and needs further research. Lastly, future investigation of epigenetic events occurring at the TSHR and other loci may give better clues for molecular based therapy of undifferentiated thyroid carcinomas. Targeted demethylating agents, histone deacetylase inhibitors combined with retinoids and specific RNAis may help treatment in the future.

Thyroid-stimulating hormone/cAMP-mediated proliferation in thyrocytes

Current research on thyrotropin-activated proliferation in the thyrocyte needs to be aimed at a better understanding of crosstalk and negative-feedback mechanisms with other proliferative pathways, especially the insulin/IGF-1-induced phosphoinositol-3 kinase pathway and the serum-induced MAPK or Wnt pathways. Convergence of proliferative pathways in mTOR is a hotspot of current research, and combined treatment using double class inhibitors for thyroid cancer may bring some success. New thyroid-stimulating hormone receptor (TSHR)-interacting proteins, a better picture of cAMP targets, a deeper knowledge of the action of the protein kinase A regulatory subunits, especially their interactions with the replication machinery, and a further understanding of mechanisms that lead to cell cycle progression through G₁/S and G₂/M checkpoints are areas that need further elucidation. Finally, massive information coming from microarray data analysis will prompt our understanding of thyroid-stimulating hormone-promoted thyrocyte proliferation in health and disease.

Serum galectin-1 and galectin-3 levels in benign and malignant nodular thyroid disease

BACKGROUND

Since the histological expression of galectins is increased in thyroid carcinoma, determination of their serum levels may provide useful preoperative information. The goal of this study was to determine if a difference in galectin serum levels could be detected between benign and malignant nodular thyroid diseases.

DESIGN

Using validated ELISAs, the concentrations of several galectins were prospectively measured in serum samples from 30 healthy individuals and preoperatively in 90 patients with thyroid disease. Seventy-one patients had multiple thyroid nodules (MTN), 13 patients had a single thyroid nodule (STN), and 6 patients had Graves' disease. Nine of 71 patients with MTN had fine-needle aspiration biopsy (FNAB) of their nodules and in 7 patients a "benign" diagnosis was made, in 0 patient a "malignant" diagnosis was made, and in 2 patients a "suspicious" diagnosis was made. Six of 13 patients with STN had FNAB of their nodules and in 2 patients a "benign" diagnosis was made, in 3 patients a "malignant" diagnosis was made, and in 1 patient a "suspicious" diagnosis was made.

RESULTS

Thyroid disease was associated with higher levels of galectins-1 and -3 compared to normal subjects. Using a threshold value of 3.2 ng/mL as a cut-off point, the measurement of serum galectin-3 separated micro- and macropapillary thyroid carcinoma (PAP_CA) from patients with nonmalignant thyroid disease with 74% specificity, 73% sensitivity, 57% positive predictive value, and 85% negative predictive value. Elevated serum galectin-3 concentrations (>3.2 ng/mL) detected 87% of macropapillary thyroid carcinomas and 67% of micropapillary thyroid carcinomas.

CONCLUSIONS

Serum levels of galectins-1 and -3 are relatively high in patients with thyroid malignancy but there is considerable overlap in serum galectin-3 concentrations between those with benign and malignant nodular thyroid disease and, to a lesser extent, between those with and without nodular thyroid disease.

Update on the molecular diagnosis of endocrine tumors: toward -omics-based personalized healthcare?

Genetic advances in endocrine neoplasia provided the paradigm for the practice of clinical cancer genetics: germline RET mutations in multiple endocrine neoplasia type 2. In the last 14 yr, both genetics and -omics advances have occurred, almost exponentially in the last 5 yr. The time has come to reevaluate recent advances in genomic medicine's promise to revolutionize personalized healthcare in the context of endocrine neoplasias. This update focuses on two examples of endocrine neoplasias, those of the thyroid and of the adrenal, and discusses recent advances in germline and somatic genetics and genomics, as they relate to clinical application.

Circulating thyroid cancer markers

PURPOSE OF REVIEW

To describe the progress in the field of circulating markers of thyroid cancer.

RECENT FINDINGS

Thyroid cancer cells in the circulation can be detected by measuring the mRNA of thyroid-specific genes. Among these, thyroglobulin, and more recently thyroid-stimulating hormone receptor mRNAs' provide high diagnostic sensitivity and specificity for thyroid cancer detection. These markers can be used in synergy with current diagnostic modalities, i.e. fine-needle aspiration and ultrasound, for preoperative diagnosis and serum thyroglobulin measurement for monitoring.

SUMMARY

For the detection of recurrent/residual thyroid cancer, serum thyroglobulin remains the sole circulating marker, but lacks sensitivity and is unreliable in the presence of antithyroglobulin antibodies. The measurement of thyroid-specific mRNA in blood may provide sensitive/specific markers, but significant variability exists among various studies for thyroglobulin mRNA in particular, questioning the validity of this marker. Recent studies have demonstrated the high sensitivity and specificity of thyroid-stimulating hormone receptor mRNA in detecting recurrent/residual disease even in the presence of thyroglobulin antibodies. Fine-needle aspiration biopsy is currently the sole method for evaluating thyroid nodules. Indeterminate fine-needle aspiration cytology is found in approximately 15-30% of specimens. Thyroid-stimulating hormone receptor mRNA measurement in patients with indeterminate fine-needle aspiration may enhance cancer detection and save unnecessary surgeries.