The role of 18F-fluorodeoxyglucose positron emission tomography in differentiated thyroid cancer before surgery

The role of 18 F-FDG-PET/CT in the management of differentiated thyroid cancer

INTRODUCTION

In previous literature, 18 F-FDG-PET/ CT imaging significantly impacted differentiated thyroid cancer (DTC) therapy. Low thyroglobulin (Tg) levels and negative Iodine-131 (131I) whole-body scan (WBS), along with negative 18 F-FDG-PET/ CT, suggested a lesser likelihood of active illness. Positive 18 F-FDG-PET/CT findings, however, were associated with a variety of signs of local recurrence and regional or distant metastases in patients with suspected WBS. We aim to evaluate the utility of 18 F-FDG-PET/CT in managing DTC patients with negative 131I post-therapy WBS and elevated Tg.

MATERIAL AND METHODS

We retrospectively reviewed 55 patients with DTC (76% papillary and 24% follicular). Patients underwent total thyroidectomy or several radioactive iodine (RAI) treatments or both. WBS was performed 5-7 days after RAI treatment. Inclusion criteria were elevated serum Tg, negative anti-Tg auto-antibodies (AbTg) during long-term follow-up, presence of 18F-FDG-PET/CT images, and negative or suspicious WBS.

RESULTS

54% of 18 F-FDG-PET/CTs detected at least one lesion, mainly, cervical lymph nodes (49.9%), mediastinal lymph nodes (40.4%), local recurrence (34%), and bone or tissue metastasis (36.2%). The three major sites of metastasis were lung, bone, and liver. 18 F-FDG-PET/CT identified recurrence or metastasis in 45% of patients with high serum Tg and negative WBS, modifying therapeutic management in half the patients for suitable treatment modality (surgery vs. tyrosine kinase inhibitor).

CONCLUSION

The findings redemonstrate that elevated Tg with negative or suspicious WBS necessitates 18 F-FDG-PET/CT for localization of recurrence. 18 F-FDG-PET/CT is useful in managing locally recurrent or metastatic DTC with high Tg levels. It influences treatment and accurately assesses disease severity.

Regulators of glucose uptake in thyroid cancer cell lines

Abstract

Thyroid cancer is the most common sort of endocrine-related cancer with more prevalent in women and elderly individuals which has quickly widespread expansion in worldwide over the recent decades. Common features of malignant thyroid cells are to have accelerated metabolism and increased glucose uptake to optimize their energy supply which provides a fundamental advantage for growth. In tumor cells the retaining of required energy charge for cell survival is imperative, indeed glucose transporters are enable of promoting of this task. According to this relation it has been reported the upregulation of glucose transporters in various types of cancers. Human studies indicated that poor survival can be occurred following the high levels of GLUT1 expression in tumors. GLUT-1 and GLUT3 are the glucose transporters which seems to be mainly engaged with the oncogenesis of thyroid cancer and their expression in malignant tissues is much more than in the normal one. They are promising targets for the advancement of anticancer strategies. The lack of oncosuppressors have dominant effect on the membrane expression of GLUT1 and glucose uptake. Overexpression of hypoxia inducible factors have been additionally connected with distant metastasis in thyroid cancers which mediates transcriptional regulation of glycolytic genes including GLUT1 and GLUT3. Though the physiological role of the thyroid gland is well illustrated, but the metabolic regulations in thyroid cancer remain evasive. In this study we discuss proliferation pathways of the key regulators and signaling molecules such as PI3K-Akt, HIF-1, MicroRNA, PTEN, AMPK, BRAF, c-Myc, TSH, Iodide and p53 which includes in the regulation of GLUTs in thyroid cancer cells. Incidence of deregulations in cellular energetics and metabolism are the most serious signs of cancers. In conclusion, understanding the mechanisms of glucose transportation in normal and pathologic thyroid tissues is critically important and could provide significant insights in science of diagnosis and treatment of thyroid disease.

Diagnostic role of F-18 FDG PET/CT for preoperative lymph node staging in thyroid cancer patients; A systematic review and metaanalysis

PURPOSE

Although ultrasonography (US) is a standard technique for the assessment of cervical lymph node (LN) metastasis, the role of F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) is increasingly reported. The purpose of this study is to assess the diagnostic accuracy of F-18 FDG PET-CT for detection of cervical LN metastasis in thyroid cancer (TCa) patients through a meta-analysis.

PATIENTS AND METHODS

The PubMed, Cochrane Database, and Embase from the earliest available date of indexing through September 31, 2019, were searched for studies evaluating the diagnostic performance of F-18 FDG PET-CT for detection of LN metastasis in TCa. We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic curves.

RESULTS

Across 9 studies (759 patients), the pooled sensitivity for F-18 FDG PET-CT for all cervical LN metastasis in TCa was 0.30 (95% CI; 0.26-0.35) a pooled specificity of 0.94. For central LN metastasis, the pooled sensitivity was 0.28 (95% CI; 0.21-0.34) and a pooled specificity was 0.87 (95% CI; 0.83-0.90). For lateral LN metastasis, the pooled sensitivity was 0.56 (95% CI; 0.50-0.62) and a pooled specificity was 0.94.

CONCLUSIONS

F-18 FDG PET-CT shows a low sensitivity and high specificity for the detection of metastatic LNs in patients with TCa. The current data suggests that F-18 FDG PET-CT is not indicated in the work up of patients with thyroid cancer or biochemical evidence of recurrent disease.

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.

PROGNOSTIC VALUE OF LYMPH NODE UPTAKE ON PRETREATMENT F-18 FDG PET/CT IN PATIENTS WITH N1B PAPILLARY THYROID CARCINOMA

Objective: The aim of this study was to investigate the prognostic value of metabolic characteristics of metastatic lymph node (LN) using pretreatment F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for patients with papillary thyroid carcinoma (PTC) and metastatic lateral LN (N1b). Methods: Ninety-six PTC patients (female:male = 72:24; median age, 44.5 years) with pathologic N1b who underwent pretreatment FDG PET/CT, total thyroidectomy, and radioactive iodine ablation were retrospectively reviewed. To predict responses to initial therapy and recurrence, clinicopathologic factors and metabolic parameters were reviewed, such as sex, age, tumor size, extranodal extension, number and ratio of metastatic LNs, serum thyroglobulin, and maximum standardized uptake value (SUVmax). Results: Among the 96 PTC patients, 81 (84.4%) were classified into the acceptable response (58 excellent; 23 indeterminate) and 15 (15.6%) into the incomplete response (8 biochemical incomplete; 7 structural incomplete) by the 2015 American Thyroid Association management guideline for differentiated thyroid carcinoma. The multivariate analysis showed that SUVmax of N1b (P = .018), pre-ablation stimulated thyroglobulin level (P = .006), and the ratio of metastatic LNs (P = .018) were related to incomplete response. The cutoff value of each variable was determined by receiver operating characteristic analysis. Nine (9.4%) patients experienced recurrences (median follow-up: 50 months). The Kaplan-Meier analysis revealed that SUVmax of N1b (cutoff value: 2.3; P = .025) and ratio of metastatic LNs (cutoff value: 0.218; P = .037) were significant prognostic factors for recurrence. Conclusion: High SUVmax of N1b cervical LN on pretreatment FDG PET/CT could predict incomplete responses to initial therapy and recurrence in patients with N1b PTC. Abbreviations: ATA = American Thyroid Association; DTC = well-differentiated thyroid carcinoma; FDG = F-18 fluorodeoxyglucose; IQR = interquartile range; LN = lymph node; N1b = metastatic lateral cervical lymph node; PET/CT = positron emission tomography/computed tomography; PTC = papillary thyroid carcinoma; RAI = radioactive iodine; ROC = receiver operating characteristic; SUVmax = maximum standardized uptake value; Tg = thyroglobulin; USG = ultrasonography.

Anterior mediastinal tumor as a solitary lymph node metastasis of occult thyroid carcinoma

Solitary metastasis of occult thyroid carcinoma to the anterior mediastinum is very rare. A 65-year-old woman was examined for anterior mediastinal tumor based on the FDG accumulation on PET. We resected the tumor by video-assisted thoracic surgery. A pathological examination revealed that the tumor was lymph node metastasis of papillary thyroid carcinoma. The postoperative examination showed that the tumor was a solitary lymph node metastasis of occult thyroid carcinoma. Primary thyroid carcinoma has not appeared in 2 years since the surgery, and careful follow-up has been continued.

THYROGLOBULIN AS A TUMOR MARKER IN DIFFERENTIATED THYROID CANCER - CLINICAL CONSIDERATIONS

SUMMARY – Initial treatment of the majority of patients with differentiated thyroid cancer (DTC) includes total thyroidectomy. Postoperative ablation therapy with radioactive iodine (I-131) is indicated in all high-risk patients, however, there is disagreement regarding its use in low- and intermediate-risk patients. Over the last few decades, thyroglobulin (Tg) has been established as the primary biochemical tumor marker for patients with DTC. Thyroglobulin can be measured during thyroid hormone therapy or after thyroid-stimulating hormone (TSH) stimulation, through thyroid hormone withdrawal or the use of human recombinant TSH. In many studies, the cut-off value for adequate Tg stimulation is a TSH value ≥30 mIU/L. However, there is an emerging body of evidence suggesting that this long-established standard should be re-evaluated, bringing this threshold into question. Recently, a risk stratification system of response to initial therapy (with four categories) has been introduced and Tg measurement is one of the main components. The relationship between the Tg/TSH ratio and the outcome of radioiodine ablation has also been studied, as well as clinical significance of serum thyroglobulin doubling-time. The postoperative serum Tg value is an important prognostic factor that is used to guide clinical management, and it is the most valuable tool in long term follow-up of patients with DTC.

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.

Correlation of BRAF mutation and SUVmax levels in thyroid cancer patients incidentally detected in 18F-fluorodeoxyglucose positron emission tomography

The prognostic importance of ¹⁸F-fluorodeoxyglucose avidity in primary thyroid tumor and molecular basis responsible for its mechanism has not yet been well characterized. In this study, we aimed to evaluate the correlation between the maximum standardized uptake levels and B-type Raf kinase mutation positivity in incidentally detected papillary thyroid cancer patients during ¹⁸F-fluorodeoxyglucose positron emission tomography examination. We retrospectively evaluated 6873 ¹⁸F-fluorodeoxyglucose-positron emission tomography scans of consecutive subjects from a database search for tumor staging in 2014 at our hospital Nuclear Medicine Center. In total, 135 patients had focal ¹⁸F-fluorodeoxyglucose uptake in the thyroid. Of these, 76 patients had fine-needle aspiration biopsy. ¹⁸F-fluorodeoxyglucose-maximum standardized uptake of the positron emission tomography-detected nodules was recorded. B-type Raf kinase (V600E) mutation and p53 protein expression were evaluated in papillary thyroid cancer patients. The incidence of thyroid incidentaloma in ¹⁸F-fluorodeoxyglucose-maximum standardized uptake scans was 2 % (135/6873). Of the 76 patients evaluated, 41 % (n = 31) were diagnosed papillary thyroid cancer. B-type Raf kinase mutation was positive in 51 % (17/30) of the papillary thyroid cancer patients. Maximum standardized uptake levels of the nodules (≥1 cm) were significantly higher in B-type Raf kinase-mutated papillary thyroid cancer patients than in non-mutated patients [16.6 (10.4-27.9) vs. 9.7 (6.8-11.1); P = 0.007]. Correlation analysis revealed that maximum standardized uptake was significantly associated with B-type Raf kinase mutation positivity (r = 0.519; P = 0.005). Logistic regression analysis showed an association between maximum standardized uptake and B-type Raf kinase mutation positivity even after adjustment for age and gender (P = 0.01). B-type Raf kinase mutation is closely related to ¹⁸F-fluorodeoxyglucose-positron emission tomography maximum standardized uptake levels in patients with incidentally detected papillary thyroid cancer.

Analysis of predictability of F-18 fluorodeoxyglucose-PET/CT in the recurrence of papillary thyroid carcinoma

Whether preoperative F-18 fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) can predict recurrence of papillary thyroid carcinoma (PTC) remains unclear. Herein, we evaluated the potential of primary tumor FDG avidity for the prediction of tumor recurrence in PTC patients. A total of 412 PTC patients (72 males, 340 females; age: 47.2 ± 12.2 years; range: 17-84 years) who underwent FDG-PET/CT prior to total thyroidectomy (n = 350), subtotal thyroidectomy (n = 2), or lobectomy (n = 60) from 2007 to 2011 were analyzed. The predictive ability for recurrence was investigated among various clinicopathological factors, BRAFV600E mutation, and preoperative FDG avidity of the primary tumor using Kaplan-Meier (univariate) and Cox proportional hazards regression (multivariate) analyses. Of the 412 patients, 19 (4.6%) experienced recurrence, which was confirmed either by pathology (n = 17) or high serum thyroglobulin level (n = 2), during a mean follow-up period of 43.9 ± 16.6 months. Of the 412 patients, 237 (57.5%) had FDG-avid tumors (maximum standardized uptake value, 7.1 ± 7.0; range: 1.6-50.5). Kaplan-Meier analysis revealed that tumor size (P = 0.0054), FDG avidity of the tumor (P = 0.0049), extrathyroidal extension (P = 0.0212), and lymph node (LN) stage (P < 0.0001) were significant predictors for recurrence. However, only LN stage remained a significant predictor in the multivariate analysis (P < 0.0001). Patients with FDG-avid tumors had higher LN stage (P < 0.0001), larger tumor size (P < 0.0001), and more frequent extrathyroidal extension (P < 0.0001). In conclusion, FDG avidity of the primary tumor in preoperative FDG-PET/CT could not predict the recurrence of PTC. LN stage was the only identified predictor of PTC recurrence.

Implication of 18F-fluorodeoxyglucose uptake by affected lymph nodes in cases with differentiated thyroid cancer

In this study, we evaluated the usefulness of positron emission tomography using ¹⁸F-fluorodeoxyglucose (FDG-PET) to detect metastatic lymph nodes in differentiated thyroid cancer. We also investigated whether certain factors, including the size of the metastasis to the lymph nodes, are associated with FDG avidity. A total of 22 consecutive patients with differentiated thyroid cancer who underwent FDG-PET preoperatively were enrolled in this study. Lymph node metastasis was diagnosed in the final pathology in 10 of the 22 patients (45.5%). The mean maximum standardized uptake value of the metastatic lymph nodes was 4.53 (range, 0-23.5). The 22 cases with differentiated thyroid cancer were divided into two groups based on lymph node metastasis. Clinicopathological variables other than FDG uptake of metastatic lymph nodes were not predictors of lymph node metastasis of thyroid cancer. The sensitivity, specificity, overall accuracy and false-negative rates of preoperative FDG-PET in the prediction of lymph node status were 40.0, 100, 72.7 and 60.0%, respectively. The false-positive rate of FDG-PET evaluation was 0%. The mean largest dimension of metastasis was 23.0 mm for FDG-positive cases and 10.9 mm for FDG-negative cases. There was a marked difference in the size of metastases between FDG-positive and -negative cases; however, even in patients with node metastasis >10 mm, the false-negative rate was 50.0%. Therefore, FDG-PET imaging was not found to be sufficient for the evaluation of lymph node status, particularly in cases with small metastases. Our findings indicate that preoperative FDG-PET evaluation of the lymph nodes cannot be considered predictive of the final pathology.

Impact of patient age on the iodine/FDG "flip-flop" phenomenon in lung metastasis from thyroid cancer

OBJECTIVES

Radioiodine therapy is an effective treatment for lung metastasis from thyroid cancer. However, cases of lung metastasis without iodine uptake are often encountered. In such cases, FDG accumulation in lung lesions is often observed. There is a reverse relationship between iodine and FDG accumulation in thyroid cancer lesions, the so-called "flip-flop" phenomenon. The aim of this study was to assess the relationship between patient age and the occurrence of the flip-flop phenomenon.

METHODS

Eighty-six patients who underwent radioiodine therapy for lung metastasis were studied retrospectively (age 17-73 years; median 60 years; males:females 22:64). We compared the clinical data and imaging findings (size and FDG uptake of lung nodules) between patients with (n = 44) and without (n = 42) iodine uptake in lung metastasis.

RESULTS

Significantly more young patients showed iodine accumulation in lung metastasis than old patients (p = 0.0025). Lung metastases with larger size or greater FDG uptake showed no iodine uptake more frequently with significant difference (p = 0.015 and <0.001, respectively). Among patients with FDG uptake in the lung metastasis, 57.1 % of young patients (<60 years) and 24.3 % of the old patients (≥60 years) showed iodine uptake (p = 0.0029).

CONCLUSIONS

Higher patient age and lung nodules with large size or FDG accumulation are negative factors for iodine accumulation in lung metastases from thyroid cancer. In addition, our results show that young patients have a greater likelihood of iodine uptake even when FDG accumulates in lung metastasis, in contrast to old patients.

Preoperative Lymph Node Staging by FDG PET/CT With Contrast Enhancement for Thyroid Cancer: A Multicenter Study and Comparison With Neck CT

Objectives

The purpose of this study was to compare lymph node (LN) staging using ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) with contrast-enhancement (CE) PET/CT and contrast-enhanced neck CT (neck CT) in patients with thyroid cancer with level-by-level comparison with various factors.

Methods

This was a retrospective multicenter study. A total of 85 patients were enrolled. Patients who underwent a preoperative evaluation by CE PET/CT and neck CT for thyroid cancer were enrolled. The gold standard for LN was the combination of surgical pathology and clinical follow-up. We compared CE PET/CT with neck CT using a level-by-level method. Factors, including age, sex, camera, arm position, tumor size, extra-thyroidal extension, tumor location, number of primary tumors, primary tumor maximum standardized uptake value, and the interval from scan to operation were also analyzed.

Results

Overall accuracy was 81.2% for CE PET/CT and 68.2% for neck CT. CE PET/CT was more sensitive than neck CT (65.8% vs. 44.7%). Also, CE PET/CT showed higher negative predictive value (77.2% vs. 66.1%). CE PET/CT showed good agreement with the gold standard (weighted kappa [κ], 0.7) for differentiating N0, N1a, and N1b, whereas neck CT showed moderate agreement (weighted κ, 0.5). CE PET/CT showed better agreement for the number of levels involved with the gold standard (weighted κ, 0.7) than that of neck CT with the gold standard (weighted κ, 0.5). The accuracies for differentiating N0, N1a, and N1b were 81.2% for CE PET/CT and 68.2% for neck CT. Level-by-level analysis showed that CE PET/CT was more sensitive and has higher negative predictive value for detecting ipsilateral level IV and level VI LNs than neck CT. Other analyzed factors were not related to accuracies of both modalities.

Conclusion

CE PET/CT was more sensitive and reliable than neck CT for preoperative LN staging in patients with thyroid cancer.

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.

Primary squamous cell carcinoma of the thyroid on FDG PET/CT

Primary squamous cell carcinoma of the thyroid is rare. We present FDG PET/CT findings on 2 male patients with primary squamous cell carcinoma of the thyroid. Elevated FDG activity was visualized on primary thyroid tumor and metastatic lesions on both patients.

Molecular Analysis by Gene Expression of Mitochondrial ATPase Subunits in Papillary Thyroid Cancer: Is ATP5E Transcript a Possible Early Tumor Marker?

BACKGROUND

Cancer development involves an "injury" to the respiratory machinery (Warburg effect) due to decreased or impaired mitochondrial function. This circumstance results in a down regulation of some of the ATPase subunits of the malignant tissue. The objective of this work was to assess and compare the relative expression of mRNA of mitochondrial ATPase subunits between samples of thyroid cancer and benign nodules.

MATERIAL AND METHODS

Samples from 31 patients who had an operation for PTC at the General Hospital of Mexico were snap-frozen and stored at -70°C. Thirty-five patients who had an operation for benign tumors were also included in the study. mRNA expression levels of alpha, beta, gamma, and epsilon subunits of F1 and "c12" of subunit Fo were determined by real-time RT-PCR (by duplicate), in order to determine if abnormal expression of these genes could partially explain the Warburg effect in papillary thyroid cancer (PTC).

RESULTS

ATP5E transcript alteration (down-expression) was highly associated to PTC diagnosis OR=11.76 (95% confidence interval, 1.245-237.98; p=0.04).

CONCLUSIONS

Relative down-expression of ATP5E transcript was highly associated with PTC diagnosis. This transcript alteration may be used as a tumoral marker in papillary thyroid cancer.

Feasibility of FDG-PET/CT for the initial diagnosis of papillary thyroid cancer

To assess the role of [18F]-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) as a preoperative diagnostic tool in papillary thyroid carcinoma (PTC). From 2011 to 2014, 197 patients with PTC (246 tumor foci in all) underwent FDG-PET. Among these patients, 46 underwent neck dissection for lateral neck metastasis. According to the FDG avidity of the tumor foci or lateral neck metastasis, factors associated with the prognostic value were evaluated by univariate and multivariate logistic regression analyses. Among the 197 patients, 7 (3.6 %) were incidentally found to have non-thyroid origin malignancy. Additionally, 63.0 % (155/246) of PTC foci showed FDG uptake on PET/CT. Univariate analysis showed that the tumor size, the presence of extrathyroidal extension, BRAF mutation, and Hashimoto thyroiditis were associated with FDG avidity. However, except for pathological extrathyroidal extension, the other factors showed statistically significant correlations with FDG avidity (p < 0.001, p = 0.008, and p = 0.009, respectively). FDG uptake in lateral neck node metastasis showed high specificity and negative predictive value (NPV). In four cases of nonspecific findings on ultrasonography (USG)/CT, FDG avidity was helpful to diagnose the presence of lateral neck metastasis. The maximum standardized uptake value (SUVmax) of PET/CT was correlated with the maximum diameter of the involved lateral node. FDG avidity did not show any significance in the recurrence-free survival of both the thyroid tumor and lateral neck metastasis. The FDG avidity of PTC did not show prognostic predictive meaning. However, in the case of lateral neck metastasis, FDG avidity showed high sensitivity and NPV, and could provide better information in cases of nonspecific findings on USG and CT.

Monitoring liver macrophages using nanobodies targeting Vsig4: concanavalin A induced acute hepatitis as paradigm

Kupffer cells (KCs) are liver resident macrophages which are important for tissue homeostasis and have been implicated in immunogenic, tolerogenic and pathogenic immune reactions depending on the insult. These cells and the biomarkers they express thus represent interesting in vivo sensors for monitoring liver inflammation. In the current study, we explored whether KCs can be monitored non-invasively using single-photon-emission computed tomography (SPECT) with (99m)Tc labeled nanobodies (Nbs) targeting selected biomarkers. Nbs targeting V-set and immunoglobulin domain-containing 4 (Vsig4) or macrophage mannose receptor (MMR) accumulated in the liver of untreated mice. The liver targeting of anti-Vsig4 Nbs, but not anti-MMR Nbs, was blunted upon depletion of macrophages, highlighting specificity of anti-Vsig4 Nbs for liver macrophage imaging. Ex vivo flow cytometry and immunohistochemistry analysis confirmed that anti-Vsig4 Nbs specifically targeted KCs but no other cell types in the liver. Upon induction of acute hepatitis using concanavalin A (ConA), down-regulation of the in vivo imaging signal obtained using anti-Vsig4 Nbs reflected reduction in KC numbers and transient modulation of Vsig4 expression on KCs. Overall, these results indicate that Nbs targeting Vsig4 as molecular imaging biomarker enable non-invasive monitoring of KCs during hepatic inflammation.