Determining tissue origin of circulating epithelial cells (CEC) in patients with differentiated thyroid cancer by real-time PCR using thyroid mRNA probes

Prospective Monitoring of Circulating Epithelial Tumor Cells (CETC) Reveals Changes in Gene Expression during Adjuvant Radiotherapy of Breast Cancer Patients

Circulating epithelial tumor cells (CETC) are considered to be responsible for the formation of metastases. Therefore, their importance as prognostic and/or predictive markers in breast cancer is being intensively investigated. Here, the reliability of single cell expression analyses in isolated and collected CETC from whole blood samples of patients with early-stage breast cancer before and after radiotherapy (RT) using the maintrac^® method was investigated. Single-cell expression analyses were performed with qRT-PCR on a panel of selected genes: GAPDH, EpCAM, NANOG, Bcl-2, TLR 4, COX-2, PIK3CA, Her-2/neu, Vimentin, c-Met, Ki-67. In all patients, viable CETC were detected prior to and at the end of radiotherapy. In 7 of the 9 (77.8%) subjects examined, the CETC number at the end of the radiotherapy series was higher than before. The majority of genes analyzed showed increased expression after completion of radiotherapy compared to baseline. Procedures and methods used in this pilot study proved to be feasible. The method is suitable for further investigation of the underlying molecular biological mechanisms occurring in cells surviving radiotherapy and possibly the development of radiation resistance.

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.

NIS and epithelial-mesenchymal transition marker expression of circulating tumor cells for predicting and monitoring the radioactive iodine-131 therapy effect in differentiated thyroid cancers

Current methods, such as serum thyroglobulin measurement and medical imaging, have limitations in the routine monitoring of the disease status and treatment response of patients with differentiated thyroid cancers (DTCs), and additional methods remain to be explored. The aim of this study was to investigate the clinical value of the sodium/iodide symporter (NIS) expression and epithelial-mesenchymal transition (EMT) phenotypes of circulating tumor cells (CTCs) in monitoring the disease status and treatment response of DTC. Blood samples were obtained from DTC patients before (1 to 3 months after total thyroidectomy) and 4 to 6 months after radioactive iodine-131 (RAI) therapy for the CTC assessments. The number, NIS expression, and EMT phenotypes of CTCs were enumerated and characterized with CanPatrol™ CTC enrichment and mRNA in situ hybridization. Postoperative NIS high expression was independently correlated with a better response to first RAI therapy and good treatment efficacy. Postoperative NIS-/epithelial-/mesenchymal+ CTCs presence was independently correlated with a worse response to first RAI therapy. The numbers of total NIS+ CTCs and NIS+/epithelial+/mesenchymal+ CTCs after first RAI therapy were negatively correlated with a better response to RAI therapy only in univariate analyses. Univariate and multivariate analyses showed that a decreased or unchanged number of total NIS+ CTCs after RAI therapy may denote good efficacy and effective RAI therapy. These preliminary data suggest that assessment of the NIS expression and EMT phenotypes of CTCs may serve as potential adjuncts for predicting and monitoring the curative effect of RAI therapy in DTC patients and avoid ineffective treatment. Further validation is warranted.

Extracellular Vesicles from Thyroid Carcinoma: The New Frontier of Liquid Biopsy

The diagnostic approach to thyroid cancer is one of the most challenging issues in oncology of the endocrine system because of its high incidence (3.8% of all new cancer cases in the US) and the difficulty to distinguish benign from malignant non-functional thyroid nodules and establish the cervical lymph node involvement during staging. Routine diagnosis of thyroid nodules usually relies on a fine-needle aspirate biopsy, which is invasive and often inaccurate. Therefore, there is an urgent need to identify novel, accurate, and non-invasive diagnostic procedures. Liquid biopsy, as a non-invasive approach for the detection of diagnostic biomarkers for early tumor diagnosis, prognosis, and disease monitoring, may be of particular benefit in this context. Extracellular vesicles (EVs) are a consistent source of tumor-derived RNA due to their prevalence in circulating bodily fluids, the well-established isolation protocols, and the fact that RNA in phospholipid bilayer-enclosed vesicles is protected from blood-borne RNases. Recent results in other types of cancer, including our recent study on plasma EVs from glioblastoma patients suggest that information derived from analysis of EVs from peripheral blood plasma can be integrated in the routine diagnostic tumor approach. In this review, we will examine the diagnostic and prognostic potential of liquid biopsy to detect tumor-derived nucleic acids in circulating EVs from patients with thyroid carcinoma.

Circulating Epithelial Cell Characterization and Correlation with Remission and Survival in Patients with Thyroid Cancer

BACKGROUND

Thyroid cancer is the most common endocrine tumor and generally has relatively good clinical outcomes. However, 15-20% of patients ultimately develop recurrence or disease-related death. The appropriate prognostic factors for thyroid cancer are still elusive. This study evaluated whether the number of circulating tumor cells/circulating epithelial cells (CECs) expressing either epithelial cell adhesion molecule (EpCAM), podoplanin (PDPN), or thyrotropin receptor (TSHR) is related to remission and disease-specific mortality (DSM) of patients with thyroid cancer.

METHODS

Blood samples were collected from patients (n = 128) after thyroidectomy or radioactive iodide therapy. CECs were enriched by lysis of red blood cells and depletion of leukocytes. Subtyping and quantification of the enriched cells were performed with immunofluorescence staining using antibodies against EpCAM, TSHR, and PDPN, respectively. Whether the number of a specific subtype of CECs is related to remission and DSM of patients was determined by univariate and multivariate analyses.

RESULTS

The EpCAM⁺-CECs, TSHR⁺-CECs, and PDPN⁺-CECs counts for patients in the non-remission group (n = 43) were significantly higher when compared to the remission group (n = 85; p < 0.001). Receiver operating characteristic analysis showed that the number of EpCAM⁺-CECs, TSHR⁺-CECs, and PDPN⁺-CECs was able to distinguish the status of remission from non-remission. The cutoff point for EpCAM⁺-CECs, TSHR⁺-CECs, and PDPN⁺-CECs was 40, 47, and 14 (cells/mL), with the accuracy of the assay equivalent to 80.4%, 76.6%, and 77.3%, respectively. On the other hand, the number of EpCAM⁺-CECs (p < 0.001), PDPN⁺-CECs (p = 0.013), and TSHR⁺-CECs (p < 0.001) for patients in the DSM group (n = 17) was significantly higher when compared to the patients who survived (n = 111). Receiver operating characteristic analysis showed that EpCAM⁺-CECs, TSHR⁺-CECs, and PDPN⁺-CECs counts were able to distinguish mortality from survival status. The cutoff point for EpCAM⁺-CECs, TSHR⁺-CECs, and PDPN⁺-CECs was 27, 25, and 9 (cells/mL), with the accuracy of the assay equivalent to 69.5%, 67.2%, and 68.5%, respectively.

CONCLUSIONS

CEC testing is a useful tool for analysis of overall survival and remission status of patients with thyroid cancer. Implementation of CEC testing into routine clinical test may be worthy to consider for patient clinical care.

CIRCULATING TUMOR CELLS IN MINIMALLY INVASIVE FOLLICULAR THYROID CARCINOMA AND BENIGN THYROID TUMORS WITH A FOLLICULAR PATTERN: PILOT EXPERIENCE

Purpose

Minimally invasive follicular thyroid carcinomas (MIFCs) are uncommon; literature offers limited guidance on their natural history and management. Starting January 2015 we measured circulating tumor cells (CTCs) in patients with MIFC (n=22) or benign thyroid tumors with follicular features (n=4).

Methods

In a retrospective analysis, we assessed detectability of and serial changes in CTC, compared demographic/clinical differences between CTC-positive versus CTC-negative subgroups using Student's t-test, and examined correlations between CTC status and serum thyroglobulin using Spearman's test. CTCs were quantitated via immunomagnetic separation/microscopic inspection.

Results

Thirteen patients (50%: 12/22 MIFC, 1/4 benign tumor) were initially CTC-positive; 3 remained CTC-positive in ≥1 subsequent measurement. CTC-positive patients had larger tumors and more frequent multifocality and vascular invasion versus CTC-negative patients (n=13). However, no tested variable differed significantly between the subgroups. After 17.2±10.5 months, neither subgroup showed evidence of disease. Significant correlation was absent (p ≥ 0.263) between CTC and Tg negativity (r = 0.243; n=13 evaluable) or initial CTC positivity and Tg positivity (r = -0.418; n=9 evaluable).

Conclusions

In the studied settings, CTC measurement is feasible, has unclear clinical/outcome implications, but may provide different information versus thyroglobulin testing. Lengthier assessment is warranted in larger series.

Circulating epithelial cells as potential biomarkers for detection of recurrence in patients of papillary thyroid carcinoma with positive serum anti-thyroglobulin antibody

BACKGROUND

Serum thyroglobulin (Tg) is not a reliable tumor marker for monitoring disease status after treatment in patients with papillary thyroid carcinoma (PTC) with positive anti-thyroglobulin antibody (TgAb). The aim of this study was to evaluate the clinical role of circulating epithelial cells (CECs) in PTC patients with positive serum TgAb and undetectable serum Tg.

METHODS

A pilot study was performed to evaluate CECs in 25 PTC patients with positive serum TgAb and undetectable serum Tg. CECs were isolated and enriched from peripheral blood with a negative selection system PowerMag. Immunofluorescence staining with anti-epithelial cell adhesion molecule (anti-EpCAM) and anti-thyroid stimulating hormone receptor (anti-TSHR) antibodies were used to define EpCAM⁺-CECs and TSHR⁺-CECs. After CECs testing, 25 patients were classified into two groups: recurrence group (n=7) and remission group (n=18) based on biopsy or imaging studies. The diagnostic accuracy and cutoff points of EpCAM⁺-CECs and TSHR⁺-CECs were evaluated using receiver operating characteristic (ROC) curves. The optimal cut-off values of CECs were determined by the Youden index (sensitivity+specificity-1).

RESULTS

The median numbers of EpCAM⁺-CECs (72.5 vs. 10.75) and TSHR⁺-CECs (54 vs. 5.25) were significantly increased in recurrence group compared to remission group. The area under the curve (AUC) showed good performance of EpCAM⁺-CECs (0.937) and TSHR⁺-CECs (0.825) to discriminate between recurrence and remission. The cut-off value for EpCAM⁺-CECs and TSHR⁺-CECs were set at 48cells/ml and 10cells/ml, respectively and showed a sensitivity (EpCAM⁺-CECs: 85.7%; TSHR⁺-CECs: 85.7%) and a specificity (EpCAM⁺-CECs: 100%; TSHR⁺-CECs: 77.8%) in predicting the recurrence.

CONCLUSIONS

Our study suggests CECs testing could be a potential biomarker to identify recurrence in PTC patients with positive serum TgAb and undetectable serum Tg.

Circulating epithelial cell counts for monitoring the therapeutic outcome of patients with papillary thyroid carcinoma

Loco-regional recurrence or distant metastasis usually leads to the death of patients with papillary thyroid carcinoma (PTC). Whether or not circulating epithelial cells (CECs) count is a valuable marker in monitoring the therapeutic outcome of PTC was investigated. Patients with PTC (n=129) were treated in our medical center and were categorized into 4 groups with excellent (n=45), biochemical incomplete (n=15), indeterminate (n=37), and structural incomplete (n=32) responses. CECs were enriched from the peripheral blood by the PowerMag negative selection system. Three subtypes of CECs expressing epithelial cell adhesion molecule (EpCAM), thyroid-stimulating hormone receptor (TSHR, a marker for thyroid cells), and podoplanin (PDPN, a marker related to poor prognosis in patients with PTC) were defined by immunofluorescence staining, respectively. The median number of CECs (cells/mL of blood) expressing EpCAM, TSHR, and PDPN was 23 (interquartile range 10-61), 19 (interquartile range 8-50), and 8 (interquartile range 3-22), respectively, for patients enrolled in this study. The number of EpCAM+-CECs, TSHR+-CECs, and PDPN+-CECs was statistically different among patients in different treatment response groups without interference from anti-thyroglobulin antibody (P<0.0001). Patients with structural incomplete response had higher counts for all three CECs subtypes when compared to other patients. EpCAM+-CECs was better in distinguishing patients with excellent response from structural incomplete response among the three subtypes of CECs. The sensitivity and specificity of the assay was 84.4% and 95.6%, respectively, when the cut off value was 39 EpCAM+-CECs/mL. CECs testing can supplement the current standard methods for monitoring the therapeutic outcome of PTC.

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.

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.

Single-cell approaches for molecular classification of endocrine tumors

PURPOSE OF REVIEW

In this review, we summarize recent developments in single-cell technologies that can be employed for the functional and molecular classification of endocrine cells in normal and neoplastic tissue.

RECENT FINDINGS

The emergence of new platforms for the isolation, analysis, and dynamic assessment of individual cell identity and reactive behavior enables experimental deconstruction of intratumoral heterogeneity and other contexts where variability in cell signaling and biochemical responsiveness inform biological function and clinical presentation. These tools are particularly appropriate for examining and classifying endocrine neoplasias, as the clinical sequelae of these tumors are often driven by disrupted hormonal responsiveness secondary to compromised cell signaling. Single-cell methods allow for multidimensional experimental designs incorporating both spatial and temporal parameters with the capacity to probe dynamic cell signaling behaviors and kinetic response patterns dependent upon sequential agonist challenge.

SUMMARY

Intratumoral heterogeneity in the provenance, composition, and biological activity of different forms of endocrine neoplasia presents a significant challenge for prognostic assessment. Single-cell technologies provide an array of powerful new approaches uniquely well suited for dissecting complex endocrine tumors. Studies examining the relationship between clinical behavior and tumor compositional variations in cellular activity are now possible, providing new opportunities to deconstruct the underlying mechanisms of endocrine neoplasia.

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.