Glucose transporter 1 expression, tumor proliferation, and iodine/glucose uptake in thyroid cancer with emphasis on poorly differentiated thyroid carcinoma

[18F]-FDG Uptake as a Marker of Residual Anaplastic and Poorly Differentiated Thyroid Carcinoma following BRAF-Targeted Therapy

BACKGROUND AND PURPOSE

Neoadjuvant BRAF-directed therapy and immunotherapy followed by surgery improves survival in patients with BRAF V600E-mutant anaplastic thyroid carcinoma (ATC), more so in those who have complete ATC pathologic response. This study assesses the ability of FDG-PET to noninvasively detect residual high-risk pathologies including ATC and poorly differentiated thyroid carcinoma (PDTC) in the preoperative setting.

MATERIALS AND METHODS

This retrospective, single-center study included consecutive BRAF V600E-mutant patients with ATC treated with at least 30 days of neoadjuvant BRAF-directed therapy and who underwent FDG-PET/CT within 30 days before surgery. The highest pathologic grade observed for every head and neck lesion resected was recorded. Each lesion on preoperative PET/CT was retrospectively characterized. The primary end point was to contrast the standardized uptake normalized by lean body mass (SULmax) for lesions with residual high-risk (ATC, PDTC) versus low-risk pathologies (papillary thyroid carcinoma, negative). An optimal SULmax threshold was then identified by using a receiver operating characteristic analysis, and the ability of this threshold to noninvasively and preoperatively risk-stratify patients by overall survival was then evaluated with a Kaplan-Meier plot.

RESULTS

Thirty patients (mean age 66.5 ± 9.0; 17 men) were included in this study, with 94 surgically sampled lesions. Of these lesions, 57 (60.6%) were low-risk (39 negative, 18 papillary thyroid carcinoma) and 37 (39.4%) were high-risk (29 ATC, 8 PDTC). FDG uptake was higher for high-risk compared with low-risk pathologies: median SULmax 5.01 (interquartile range [IQR] 2.81-10.95) versus 1.29 (IQR 1.06-3.1) (P < .001, Mann-Whitney U test). The sensitivity, specificity, and accuracy for detecting high-risk pathologies at the optimal threshold of SULmax ≥2.75 were 0.784 [95% CI, 0.628-0.886], 0.702 [95% CI, 0.573-0.805], and 0.734 [95% CI, 0.637-0.813], respectively. Patients with at least 1 high-risk lesion identified with the aforementioned cutoff had a worse prognosis compared with patients without high-risk lesions in the head and neck: median overall survival for the former group was 259 days and was not attained for the latter (P = .038, log-rank test).

CONCLUSIONS

Preoperative FDG-PET noninvasively identifies lesions with residual high-risk pathologies following neoadjuvant BRAF-directed targeted therapy and immunotherapy for BRAF-mutated ATC. FDG-PET avidity may serve as an early prognostic marker that correlates with residual high-risk pathology in BRAF-mutated ATC after neoadjuvant therapy.

68 Ga-DOTATATE PET/CT Versus 18 F-FDG PET/CT in TENIS Syndrome: A Head-to-Head Comparison With Elevated and Suppressed TSH Levels in Papillary Thyroid Carcinoma-A Pilot Study

BACKGROUND

TENIS syndrome is characterized by reduced expression of sodium-iodine symporter, rising serum thyroglobulin (Tg) levels, and negative whole-body 131 I scans. In such patients, somatostatin receptor imaging with 68 Ga-DOTATATE PET/CT (somatostatin receptor [SSR] PET/CT) and 18 F-FDG PET/CT (FDG PET/CT) can identify metastases and were compared under 2 conditions: elevated (eTSH) and suppressed (sTSH) TSH serum levels. Potential candidates for peptide receptor radionuclide therapy (PRRNT) were identified in 15 patients prospectively enrolled. All patients underwent 4 examinations. Images were blindly evaluated for differences in SUV max values and lesion detectability. Reference standard consisted of neck ultrasound, CT, MRI, PET/CT, biopsy, and follow-up. Three patients were received PRRNT.

RESULTS

sTSH SSR PET/CT detected a greater number of cervical ( P = 0.0253 and P = 0.0176) and distant LNs ( P = 0.0253 and P = 0.0391) when compared with sTSH FDG PET/CT, respectively, in a per-patient and on a per-lesion based analysis. Likewise, eTSH SSR PET/CT detected a greater number of patients with local recurrences ( P = 0.0455) and distant LN metastases ( P = 0.0143). Per-lesion analysis revealed greater number of cervical and distant LNs ( P = 0.0337 and P = 0.0039, respectively) when compared with eTSH FDG PET/CT. There was no difference in detection of distant metastases by both tracers for lung and bone metastases (κ = 1). Both skeletal and pulmonary lesions were also detected by conventional CT part of FDG or DOTATATE PET/CT scans. TSH stimulation had no additional value in a per-patient analysis for both FDG and DOTATATE PET scans (κ varying from 0.6087 to 1). However, TSH stimulation led to more lesion identifications in DOTATATE PET/CT; most of those metastases were not confirmed by the reference standard leading to a decrease in specificity (84% vs 74%). One of 3 patients submitted to 3 cycles of PRRNT presented with a visual partial response, a 20% reduction in quantitative analyses, and stable disease regarding Tg and TgAb levels.

CONCLUSIONS

Patients with TENIS syndrome can be imaged with SSR PET/CT as well as FDG PET/CT with high overall accuracy regardless of TSH levels (86% to 92% and 92% to 85%, respectively, with eTSH and sTSH). SSR PET/CT detected a greater number of locoregional and distant LN metastases than FDG PET/CT with both sTSH and eTSH. One of 3 patients submitted to PRRNT presented a partial response to treatment. Our findings may impact in patient restaging, management, and theranostics strategies with radiolabeled somatostatin analogs.

A narrative review: exploring viral-induced malignancies through the lens of dysregulated cellular metabolism and glucose transporters

INTRODUCTION

In this narrative review, we unravel the complex interplay between oncogenic viruses, cellular metabolism, and glucose transporter (GLUT) dysregulation in viral-induced malignancies.

METHODS

By explaining the diverse mechanisms through which seven major oncoviruses manipulate metabolic pathways and GLUT expression, particularly GLUT1, we provide novel insights into the critical role of metabolic reprogramming in viral replication and oncogenesis.

RESULTS

Our exploration of the molecular pathways targeted by viral oncoproteins reveals a similarity between the metabolic alterations induced by viral infections and those observed in neoplastic transformation. A key finding of our review is the overexpression of GLUTs, particularly GLUT1, as a hallmark of both viral infections and many cancers.

CONCLUSIONS

By elucidating the complex interplay between viral oncoproteins, oncogene activation, tumor suppressor gene loss, and GLUT overexpression, we highlight the potential of GLUTs as novel targets for diagnosis, prognosis, and therapy of viral-induced malignancies.

Role of [18F]FDG PET/CT in the management of follicular cell-derived thyroid carcinoma

Follicular cell-derived thyroid carcinomas constitute the majority of thyroid malignancies. This heterogeneous group of tumours includes well differentiated, poorly differentiated, and undifferentiated forms, which have distinct pathological features, clinical behaviour, and prognosis. Positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose combined with computed tomography ([18F]FDG PET/CT) is an imaging modality used in routine clinical practice for oncological patients. [18F]FDG PET/CT has emerged as a valuable tool for identifying patients at high risk of poor clinical outcomes and for facilitating individualized clinical decision-making. The aim of this comprehensive review is to summarize current knowledge regarding the role of [18F]FDG PET/CT in primary diagnosis, treatment, and follow-up of follicular cell-derived thyroid carcinomas considering the degree of differentiation. Controversial issues, including significance of accidentally detected [18F]FDG uptake in the thyroid, the role of [18F]FDG PET/CT in the early assessment of response to molecular targeted therapies, and its prognostic value are discussed in detail.

Match Point: Nuclear Medicine Imaging for Recurrent Thyroid Cancer in TENIS Syndrome-Systematic Review and Meta-Analysis

Background/Objectives: Disease recurrence and resistance to radioiodine (RAI) therapy are major challenges in the management of differentiated thyroid cancer (DTC). In particular, the TENIS (Thyroglobulin Elevated Negative Iodine Scintigraphy) syndrome, characterised by elevated thyroglobulin (Tg) serum levels in addition to a negative radioiodine whole body scan (WBS), complicates disease monitoring and treatment decisions. Conventional imaging techniques often fail to detect disease in WBS-negative patients with rising Tg levels, leading to limitations in therapeutic intervention. This systematic review and meta-analysis aims to evaluate the diagnostic accuracy of nuclear imaging modalities in detecting disease recurrence in patients with the TENIS syndrome and to provide insights to guide therapeutic approaches in this complex clinical scenario. Methods: A comprehensive search of PubMed/MEDLINE and EMBASE databases up to March 2024 was performed according to PRISMA guidelines. Eligible studies were selected, and quality assessment was performed with the QUADAS-2 tool. For each study, relevant data were extracted and synthesised. A meta-analysis of the diagnostic accuracy of [18F]FDG PET/CT was performed, and patient-based pooled sensitivity and specificity were calculated using a random-effects model. Statistical heterogeneity between studies was assessed using the I2 statistic. Results: Of the 538 studies initially identified, 22 were included in the systematic review, of which 18 were eligible for meta-analysis. The eligible studies, mainly focused on [18F]FDG PET/CT, showed variable sensitivity and specificity for the detection of RAI-refractory thyroid cancer lesions. For [18F]FDG PET/CT, pooled estimates displayed a sensitivity of 0.87 (95% CI: 0.82-0.90) and a specificity of 0.76 (95% CI: 0.61-0.86), with moderate heterogeneity between studies. Conclusions: [18F]FDG PET/CT remains central in the detection of disease recurrence in patients with the TENIS syndrome. The emergence of novel radiopharmaceuticals with specific molecular targets is a promising way to overcome the limitations of [18F]FDG in these patients and to open new theranostics perspectives. This review highlights the great potential of nuclear medicine in guiding therapeutic strategies for RAI-refractory thyroid cancer.

Clinical and Paraclinical Considerations Regarding ki67's Role in the Management of Differentiated Thyroid Carcinoma-A Literature Review

Background and Objectives: The ki67 nuclear protein is a tool for diagnosis and prognosis in oncology that is used to evaluate cell proliferation. Differentiated thyroid carcinoma is usually a slow-growing neoplasm, the most common type being the papillary form. Some clinical and pathological aspects may predict aggressive behaviour. There are reported cases of recurrence without clinico-pathological findings of aggressiveness. To obtain better predictions of the disease outcome in thyroid carcinoma, many immunohistochemical markers have been studied. The aim of this narrative literature review is to identify the benefits that ki67 may add to the management of patients with differentiated thyroid carcinoma, according to the latest evidence. Materials and Methods: We performed a search on the PubMed and Google Scholar databases using controlled vocabulary and keywords to find the most suitable published articles. A total number of sixty-eight items were identified, and five other articles were selected from other sources. After refining the selection, the inclusion criteria and exclusion criteria were applied, and a total number of twenty-nine articles were included in this literature review. Results and Discussion: The studies consist of retrospective studies (89.66%), case reports (6.9%) and literature reviews (3.45%), evaluating the role, implications and other parameters of ki67 as a diagnostic and/or prognostic tool. The statistical correlations between ki67 and other features were systematized as qualitative results of this review in order to improve the treatment strategies presented in the included articles. Conclusions: The included studies present converging data regarding most of the aspects concerning ki67. The ki67 proliferation index is a diagnostic/prognostic tool of interest in differentiated thyroid carcinoma and a good predictor of disease-free survival, disease recurrence and metastatic development. Prospective studies on large cohorts may add value for ki67 as a specific tool in the management strategy of differentiated thyroid carcinoma.

Unexpected focal fluorodeoxyglucose uptake in main organs; pass through or pass by?

Since the inception of fluorine-18 fluorodeoxyglucose (F-18 FDG), positron emission tomography/computed tomography (PET/CT) utilizing F-18 FDG has become widely accepted as a valuable imaging modality in the field of oncology, with global prevalence in clinical practice. Given that a single Torso PET/CT scan encompasses the anatomical region from the skull base to the upper thigh, the detection of incidental abnormal focal hypermetabolism in areas of limited clinical interest is both feasible and not uncommon. Numerous investigations have been undertaken to delineate the distinctive features of these findings, yet the outcomes have proven inconclusive. The incongruent results of these studies present a challenge for physicians, leaving them uncertain about the appropriate course of action. This article provides a succinct overview of the characteristics of fluorodeoxyglucose, followed by a comprehensive discussion of the imaging findings and clinical significance associated with incidental focal abnormal F-18 FDG activity in several representative organs. In conclusion, while the prevalence of unrecognized malignancy varies across organs, malignancies account for a substantial proportion, ranging from approximately one-third to over half, of incidental focal uptake. In light of these rates, physicians are urged to exercise vigilance in not disregarding unexpected uptake, facilitating more assured clinical decisions, and advocating for further active evaluation.

Positron Emission Tomography/Computed Tomography in Thyroid Cancer: An Updated Review

PET/computed tomography (CT) is a valuable hybrid imaging modality for the evaluation of thyroid cancer, potentially impacting management decisions. 18F-fluorodeoxyglucose (FDG) PET/CT has proven utility for recurrence evaluation in differentiated thyroid cancer (DTC) patients having thyroglobulin elevation with negative iodine scintigraphy. Aggressive histologic subtypes such as anaplastic thyroid cancer shower higher FDG uptake. 18F-FDOPA is the preferred PET tracer for medullary thyroid cancer. Fibroblast activation protein inhibitor and arginylglycylaspartic acid -based radiotracers have emerged as promising PET agents for radioiodine refractory DTC patients with the potential for theranostic application.

Diagnostic Performance of [18F]TFB PET/CT Compared with Therapeutic Activity [131I]Iodine SPECT/CT and [18F]FDG PET/CT in Recurrent Differentiated Thyroid Carcinoma

[18F]tetrafluoroborate ([18F]TFB) is an emerging PET tracer with excellent properties for human sodium iodide symporter (NIS)-based imaging in patients with differentiated thyroid cancer (DTC). The aim of this study was to compare [18F]TFB PET with high-activity posttherapeutic [131I]iodine whole-body scintigraphy and SPECT/CT in recurrent DTC and with [18F]FDG PET/CT in suspected dedifferentiation. Methods: Twenty-six patients treated with high-activity radioactive [131I]iodine therapy (range, 5.00-10.23 GBq) between May 2020 and November 2022 were retrospectively included. Thyroid-stimulating hormone was stimulated by 2 injections of recombinant thyroid-stimulating hormone (0.9 mg) 48 and 24 h before therapy. Before treatment, all patients underwent [18F]TFB PET/CT 40 min after injection of a median of 321 MBq of [18F]TFB. To study tracer kinetics in DTC lesions, 23 patients received an additional scan at 90 min. [131I]iodine therapeutic whole-body scintigraphy and SPECT/CT were performed at a median of 3.8 d after treatment. Twenty-five patients underwent additional [18F]FDG PET. Two experienced nuclear medicine physicians evaluated all imaging modalities in consensus. Results: A total of 62 suspected lesions were identified; of these, 30 lesions were [131I]iodine positive, 32 lesions were [18F]TFB positive, and 52 were [18F]FDG positive. Three of the 30 [131I]iodine-positive lesions were retrospectively rated as false-positive iodide uptake. Tumor-to-background ratio measurements at the 40- and 90-min time points were closely correlated (e.g., for the tumor-to-background ratio for muscle, the Pearson correlation coefficient was 0.91; P < 0.001; n = 49). We found a significant negative correlation between [18F]TFB uptake and [18F]FDG uptake as a potential marker for dedifferentiation (Pearson correlation coefficient, -0.26; P = 0.041; n = 62). Conclusion: Pretherapeutic [18F]TFB PET/CT may help to predict the positivity of recurrent DTC lesions on [131I]iodine scans. Therefore, it may help in the selection of patients for [131I]iodine therapy. Future prospective trials for iodine therapy guidance are warranted. Lesion [18F]TFB uptake seems to be inversely correlated with [18F]FDG uptake and therefore might serve as a dedifferentiation marker in DTC.

The potential role of reprogrammed glucose metabolism: an emerging actionable codependent target in thyroid cancer

Although the incidence of thyroid cancer is increasing year by year, most patients, especially those with differentiated thyroid cancer, can usually be cured with surgery, radioactive iodine, and thyroid-stimulating hormone suppression. However, treatment options for patients with poorly differentiated thyroid cancers or radioiodine-refractory thyroid cancer have historically been limited. Altered energy metabolism is one of the hallmarks of cancer and a well-documented feature in thyroid cancer. In a hypoxic environment with extreme nutrient deficiencies resulting from uncontrolled growth, thyroid cancer cells utilize "metabolic reprogramming" to satisfy their energy demand and support malignant behaviors such as metastasis. This review summarizes past and recent advances in our understanding of the reprogramming of glucose metabolism in thyroid cancer cells, which we expect will yield new therapeutic approaches for patients with special pathological types of thyroid cancer by targeting reprogrammed glucose metabolism.

FDG uptake reflects an immune-enriched subtype of thyroid cancer: Clinical implications of imaging-based molecular characterization

INTRODUCTION

Iodine and FDG uptakes have been established as methods to define the biological properties of thyroid cancer. As various cells in the tumor microenvironment (TME) affect tumor metabolism, we investigated the association between glucose metabolism in thyroid cancer and the TME using transcriptomic analyses.

METHODS

We used F-18 FDG PET and RNA sequencing data of thyroid cancer to find associations between TME cell types and glucose metabolism. In addition, publicly available single-cell RNA sequencing data of papillary thyroid cancer was used to investigate glucose metabolism in cell types of the TME. The correlations between the FDG uptake and biological properties of the TME, including glucose metabolism and tumor differentiation score (TDS) were evaluated. Estimation of the proportions of immune and cancer cells (EPIC) was performed. The biological properties of each cell type were also assessed in the single-cell RNA sequencing data.

RESULTS

FDG uptake showed a positive correlation with the enrichment score of macrophages and glycolysis activity. In single-cell RNA sequencing, immune cells had both high glucose transporters (GLUTs) and glycolysis signatures, while thyrocytes including cancer cells showed relatively low GLUTs and glycolysis signatures, suggesting that FDG uptake mainly occurred in immune cells of the TME. Moreover, the high GLUTs of myeloid cells were negatively associated with TDS.

CONCLUSIONS

Our findings suggest that thyroid cancer with high FDG uptake can be mediated by enriched immune cells of the TME. We suggest that FDG uptake in thyroid cancer could be a marker for the immune-rich type and provide clinical implications for treatment stratification.

Correlation between metabolic uptake of F-18-FDG-PET/computed tomography and thyroglobulin level in differentiated thyroid cancer patients with suspected recurrence

OBJECTIVE

Our objective is to determine if there is correlation between serum thyroglobulin and SUVmax of the main lesion detected in F18-FDG-PET/CT scan, in differentiated thyroid cancer (DTC) patients with suspected recurrence.

METHODS

All DTC patients enrolled in this prospective study, received at least one dose of radioactive iodine. During follow-up, they are suspected to have a recurrence due to elevated tumor markers although negative iodine whole-body scans. For all patients, F18-FDG-PET/CT scanning was performed. A 3D volume of interest was generated over the liver and main lesion to obtain maximum standardized uptake value (SUVmax). We calculated the lesion/liver ratio. Follow-up and/or histopathological examination were the gold standard. Pearson's correlation coefficient was calculated between thyroglobulin and SUVmax of the main lesion.

RESULTS

Sixty-eight patients were recruited in this study. F18-FDG-PET/CT identified suspicious malignant lesions in 42 patients, equivocal in 18 patients, while 8 patients showed no abnormal findings. Fifty-two, 6, 8, and 2 patients were true positive, true negative, false positive, and false negative respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 72%, 57% 87%, 35%, and 69% respectively. The median SUVmax and lesion/liver ratio were significantly higher in the malignant lesions than that of benign lesions (3.9 vs. 1.3 and 1.45 vs. 0.54 respectively). We found that the main lesion SUVmax and lesion/liver ratio have a positive moderate correlation with thyroglobulin (0.338 and 0.325 respectively).

CONCLUSION

In DTC patients with suspected recurrence, SUVmax of F18-FDG-PET/CT lesion showed a moderate positive correlation with serum thyroglobulin.

GLUT1 and PKM2 may be useful prognostic predictors in patients with non‑small cell lung cancer following curative R0 resection

Lung cancer has a poor prognosis despite recent progresses being made regarding its treatment. In addition, there is a paucity of reliable and independent prognostic predictors for non-small cell lung cancer (NSCLC) following curative resection. Glycolysis is associated with the malignancy and proliferation of cancer cells. Glucose transporter 1 (GLUT1) promotes glucose uptake, whereas pyruvate kinase M2 (PKM2) promotes anaerobic glycolysis. The present study aimed to evaluate the relationship between the expression of GLUT1 and PKM2 and the clinicopathological features of patients with NSCLC, and to identify a reliable prognostic factor for NSCLC following curative resection. Patients with NSCLC who underwent curative surgery were retrospectively enrolled to the present study. GLUT1 and PKM2 expression was assessed using immunohistochemistry. Subsequently, the association between the clinicopathological features of patients with NSCLC and the expression of GLUT1 and PKM2 was assessed. Of the 445 patients with NSCLC included in the present study, 65 (15%) were positive for both GLUT1 and PKM2 expression (G+/P+ group). GLUT1 and PKM2 positivity was significantly associated with sex, absence of adenocarcinoma, lymphatic invasion and pleural invasion. Furthermore, patients with NSCLC in the G+/P+ group presented significantly poorer survival rates than those expressing other markers. G+/P+ expression was significantly associated with poor disease-free survival. In conclusion, the findings of the present study indicated that the combination of GLUT1 and PKM2 may be considered a reliable prognostic factor for patients with NSCLC following curative resection, especially in patients with stage I NSCLC.

Radioiodine therapy in advanced differentiated thyroid cancer: Resistance and overcoming strategy

Thyroid cancer is the most prevalent endocrine tumor and its incidence is fast-growing worldwide in recent years. Differentiated thyroid cancer (DTC) is the most common pathological subtype which is typically curable with surgery and Radioactive iodine (RAI) therapy (approximately 85%). Radioactive iodine is the first-line treatment for patients with metastatic Papillary Thyroid Cancer (PTC). However, 60% of patients with aggressive metastasis DTC developed resistance to RAI treatment and had a poor overall prognosis. The molecular mechanisms of RAI resistance include gene mutation and fusion, failure to transport RAI into the DTC cells, and interference with the tumor microenvironment (TME). However, it is unclear whether the above are the main drivers of the inability of patients with DTC to benefit from iodine therapy. With the development of new biological technologies, strategies that bolster RAI function include TKI-targeted therapy, DTC cell redifferentiation, and improved drug delivery via extracellular vesicles (EVs) have emerged. Despite some promising data and early success, overall survival was not prolonged in the majority of patients, and the disease continued to progress. It is still necessary to understand the genetic landscape and signaling pathways leading to iodine resistance and enhance the effectiveness and safety of the RAI sensitization approach. This review will summarize the mechanisms of RAI resistance, predictive biomarkers of RAI resistance, and the current RAI sensitization strategies.

Usefulness of pyruvate dehydrogenase-E1α expression to determine SUVmax cut-off value of [18F]FDG-PET for predicting lymph node metastasis in lung cancer

A more accurate cut-off value of maximum standardized uptake value (SUVmax) in [¹⁸F]fluorodeoxyglucose positron emission tomography/computed tomography ([¹⁸F]FDG-PET/CT) is necessary to improve preoperative nodal staging in patients with lung cancer. Overall, 223 patients with lung cancer who had undergone [¹⁸F]FDG-PET/CT within 2 months before surgery were enrolled. The expression of glucose transporter-1, pyruvate kinase-M2, pyruvate dehydrogenase-E1α (PDH-E1α), and carbonic anhydrase-9 was evaluated by immunohistochemistry. Clinicopathological background was retrospectively investigated. According to PDH-E1α expression in primary lesion, a significant difference (p = 0.021) in SUVmax of metastatic lymph nodes (3.0 with PDH-positive vs 4.5 with PDH-negative) was found, but not of other enzymes. When the cut-off value of SUVmax was set to 2.5, the sensitivity and specificity were 0.529 and 0.562, respectively, and the positive and negative predictive values were 0.505 and 0.586, respectively. However, when the cut-off value of SUVmax was set according to PDH-E1α expression (2.7 with PDH-positive and 3.2 with PDH-negative), the sensitivity and specificity were 0.441 and 0.868, respectively, and the positive and negative predictive values were 0.738 and 0.648, respectively. The SUVmax cut-off value for metastatic lymph nodes depends on PDH-E1α expression in primary lung cancer. The new SUVmax cut-off value according to PDH-E1α expression showed higher specificity for [¹⁸F]FDG-PET in the diagnosis of lymph node metastasis.

Role of PET/Computed Tomography in Elderly Thyroid Cancer: Tumor Biology and Clinical Management

PET/computed tomography (CT) studies can be potentially useful in elderly thyroid carcinoma patients for exploring the disease biology, especially in metastatic setting and thereby directing appropriate therapeutic management on case-to-case basis, adopting nuclear theranostics, and disease prognostication. With the availability of multiple PET radiopharmaceuticals, it would be worthwhile to evolve and optimally use FDG and the other non-fluorodeoxyglucose and investigational PET/CT tracers as per the clinical situation and need and thereby define their utilities in a given case scenario. In this regard, (I) differentiated thyroid carcinoma (DTC) including radioiodine refractory disease, poorly differentiated thyroid cancer (PDTC) and TENIS, (II) medullary thyroid carcinoma (MTC), (III) anaplastic carcinoma and (IV) Primary thyroid lymphoma (PTL) should be viewed and dealt separately.

Reprogramming of Cellular Metabolism and Its Therapeutic Applications in Thyroid Cancer

Metabolism is a series of life-sustaining chemical reactions in organisms, providing energy required for cellular processes and building blocks for cellular constituents of proteins, lipids, carbohydrates and nucleic acids. Cancer cells frequently reprogram their metabolic behaviors to adapt their rapid proliferation and altered tumor microenvironments. Not only aerobic glycolysis (also termed the Warburg effect) but also altered mitochondrial metabolism, amino acid metabolism and lipid metabolism play important roles for cancer growth and aggressiveness. Thus, the mechanistic elucidation of these metabolic changes is invaluable for understanding the pathogenesis of cancers and developing novel metabolism-targeted therapies. In this review article, we first provide an overview of essential metabolic mechanisms, and then summarize the recent findings of metabolic reprogramming and the recent reports of metabolism-targeted therapies for thyroid cancer.

Additive value of 18FDG-PET/CT to positive 131I whole body scan in recurrent differentiated thyroid cancer patients with potential influence on treatment strategy: single Egyptian center experience

Background

Years ago the utility of of18F-fluorodeoxyglucose-positron emission tomography/computerized tomography (18FDG-PET/CT) in differentiated thyroid cancer was confined mainly to cases with elevated serum thyroglobulin and negative 131I whole body scan. In this study, we try to assess the diagnostic performance of 18FDG-PET/CT in recurrent differentiated thyroid cancer patients with positive 131I whole body scan and in addition to evaluate the impact of 18FDG-PET/CT on the treatment strategy.

Results

The 18FDG PET/CT detected tumor recurrence in 35 (81.3%) patients most of them (91.4%) were in stage IV, while the rest 8.5% was in stage III. No recurrence was detected among patients in stage II and III by 18FDG PET/CT.

Regarding lesion-based analysis, sensitivity of 18FDG-PET/CT was superior to that of 131I post-therapeutic whole body scan (TxWBS) (78.2% vs. 69.4%, respectively), while both modalities had the same specificity (50%). 18FDG-PET/CT changed the treatment plan in 18 (41.6%) patients.

Conclusion

18FDG-PET/CT may be complementary to 131ITxWBS in high-risk DTC with impact on treatment strategy.

[18F]FDG Uptake and Expression of Immunohistochemical Markers Related to Glycolysis, Hypoxia, and Proliferation in Indeterminate Thyroid Nodules

PURPOSE

The current study explored the association between 2-[¹⁸F]fluoro-2-deoxy-D-glucose ([¹⁸F]FDG) uptake and the quantitative expression of immunohistochemical markers related to glucose metabolism, hypoxia, and cell proliferation in benign and malignant thyroid nodules of indeterminate cytology.

PROCEDURES

Using a case-control design, 24 patients were selected from participants of a randomized controlled multicenter trial (NCT02208544) in which [¹⁸F]FDG-PET/CT and thyroid surgery were performed for Bethesda III and IV nodules. Three equally sized groups of [¹⁸F]FDG-positive malignant, [¹⁸F]FDG-positive benign, and [¹⁸F]FDG-negative benign nodules were included. Immunohistochemical staining was performed for glucose transporters (GLUT) 1, 3, and 4; hexokinases (HK) 1 and 2; hypoxia-inducible factor-1 alpha (HIF1α; monocarboxylate transporter 4 (MCT4); carbonic anhydrase IX (CA-IX); vascular endothelial growth factor (VEGF); sodium-iodide symporter (NIS); and Ki-67. Marker expression was scored using an immunoreactive score. Unsupervised cluster analysis was performed. The immunoreactive score was correlated to the maximum and peak standardized uptake values (SUV_max, SUV_peak) and SUV_max ratio (SUV_max of nodule/background SUV_max of contralateral, normal thyroid) of the [¹⁸F]FDG-PET/CT using the Spearman's rank correlation coefficient and compared between the three groups using Kruskal-Wallis tests.

RESULTS

The expression of GLUT1, GLUT3, HK2, and MCT4 was strongly positively correlated with the SUV_max, SUV_peak, and SUV_max ratio. The expression of GLUT1 (p = 0.009), HK2 (p = 0.02), MCT4 (p = 0.01), and VEGF (p = 0.007) was statistically significantly different between [¹⁸F]FDG-positive benign nodules, [¹⁸F]FDG-positive thyroid carcinomas, and [¹⁸F]FDG-negative benign nodules. In both [¹⁸F]FDG-positive benign nodules and [¹⁸F]FDG-positive thyroid carcinomas, the expression of GLUT1, HK2, and MCT4 was increased as compared to [¹⁸F]FDG-negative benign nodules. VEGF expression was higher in [¹⁸F]FDG-positive thyroid carcinomas as compared to [¹⁸F]FDG-negative and [¹⁸F]FDG-positive benign nodules.

CONCLUSIONS

Our results suggest that [¹⁸F]FDG-positive benign thyroid nodules undergo changes in protein expression similar to those in thyroid carcinomas. To expand the understanding of the metabolic changes in benign and malignant thyroid nodules, further research is required, including correlation with underlying genetic alterations.

Identification of super-enhancer-associated transcription factors regulating glucose metabolism in poorly differentiated thyroid carcinoma

This study aimed to uncover transcription factors that regulate super-enhancers involved in glucose metabolism reprogramming in poorly differentiated thyroid carcinoma (PDTC). TCA cycle and pyruvate metabolism were significantly enriched in PDTC. Differentially expressed genes in PDTC vs. normal control tissues were located in key steps in TCA cycle and pyruvate metabolism. A total of 23 upregulated genes localized in TCA cycle and pyruvate metabolism were identified as super-enhancer-controlled genes. Transcription factor analysis of these 23 super-enhancer-controlled genes related to glucose metabolism was performed, and 20 transcription factors were obtained, of which KLF12, ZNF281 and RELA had a significant prognostic impact. Regulatory network of KLF12, ZNF281 and RELA controlled the expression of these four prognostic target genes (LDHA, ACLY, ME2 and IDH2). In vitro validation showed that silencing of KLF12, ZNF281 and RELA suppressed proliferation, glucose uptake, lactate production and ATP level, but increased ADP/ATP ratio in PDTC cells. In conclusion, KLF12, ZNF281 and RELA were identified as the key transcription factors that regulate super-enhancer-controlled genes related to glucose metabolism in PDTC. Our findings contribute to a deeper understanding of the regulatory mechanisms associated with glucose metabolism in PDTC, and advance the theoretical development of PDTC-targeted therapies.

Strategies for Radioiodine Treatment: What’s New

Radioiodine treatment (RAI) represents the most widespread and effective therapy for differentiated thyroid cancer (DTC). RAI goals encompass ablative (destruction of thyroid remnants, to enhance thyroglobulin predictive value), adjuvant (destruction of microscopic disease to reduce recurrences), and therapeutic (in case of macroscopic iodine avid lesions) purposes, but its use has evolved over time. Randomized trial results have enabled the refinement of RAI indications, moving from a standardized practice to a tailored approach. In most cases, low-risk patients may safely avoid RAI, but where necessary, a simplified protocol, based on lower iodine activities and human recombinant TSH preparation, proved to be just as effective, reducing overtreatment or useless impairment of quality of life. In pediatric DTC, RAI treatments may allow tumor healing even at the advanced stages. Finally, new challenges have arisen with the advancement in redifferentiation protocols, through which RAI still represents a leading therapy, even in former iodine refractory cases. RAI therapy is usually well-tolerated at low activities rates, but some concerns exist concerning higher cumulative doses and long-term outcomes. Despite these achievements, several issues still need to be addressed in terms of RAI indications and protocols, heading toward the RAI strategy of the future.

Functional and molecular thyroid imaging

Nuclear medicine methods were introduced in the 1940s for thyroid disease diagnosis and therapy. They is still a crucial part of thyroid nodules work-up. Thyroid imaging with iodine or iodine-analog isotopes is widely employed in patients with thyrotoxicosis and remains the only examination able to prove the presence of autonomously functioning thyroid tissue, which excludes malignancy with a high probability. In addition, technetium-99m-methoxyisobutylisonitrile ([^99mTc]Tc-MIBI) scintigraphy and positron emission tomography/computed tomography (PET/CT) with ¹⁸F-fluoro-2-deoxy-d-glucose ([¹⁸F]FDG) are able to avoid unnecessary surgical procedures for cytologically inconclusive thyroid nodules, as confirmed by meta-analysis and cost-effectiveness studies. All considered thyroid molecular imaging allows functional characterization of different thyroid diseases, even before clinical symptoms become manifest, and remains integral to the management of such conditions. This paper summarizes main concepts of thyroid scintigraphy and its clinical use. In addition, it elaborates development of thyroid scintigraphy, as well as thyroid molecular imaging in patients with thyroid nodules and thyrotoxicosis.

Thyroid functional and molecular imaging

Radioiodine uptake (RAIU) test with iodine-123 (Na[¹²³I]I) or iodine-131 (Na[¹³¹I]I) enables accurate evaluation and quantification of iodine uptake and kinetics within thyroid cells. Thyroid Scintigraphy (TS) employing Na[¹²³I]I or ^99mTc-pertechnetate (Na[^99mTc]TcO₄) provides information regarding the function and topographical distribution of thyroid cells activity, including detection and localization of ectopic thyroid tissue. Destructive thyrotoxicosis is characterized by low RAIU with scintigraphically reduced radiotracer activity in the thyroid tissue, while productive thyrotoxicosis (i.e. hyperthyroidism "stricto sensu") is characterized by high RAIU with scintigraphically diffuse (i.e. Graves' Disease, GD and diffuse thyroid autonomy) or focal (i.e. autonomously functioning thyroid nodules, AFTN) overactivity. Accordingly, RAIU and/or TS are widely used to differentiate different causes of thyrotoxicosis. In addition, several radiopharmaceuticals are also available to help differentiate benign from malignant thyroid nodules and inform clinical decision-making: scintigraphic identification of AFTNs obviate fine-needle aspiration (FNA) biopsy, and [^99mTc]Tc-hexakis-(2‑methoxy-2-isobutyl isonitrile ([^99mTc]Tc-MIBI) and/or ¹⁸F-fluoro-d-glucose ([¹⁸F]FDG) may complement the work-up of cytologically indeterminate "cold" nodules for reducing the need for diagnostic lobectomies/thyroidectomies. Finally, RAIU studies are also useful for calculating the administered therapeutic activity of Na[¹³¹I]I to treat hyperthyroidism and euthyroid multinodular goiter. All considered, thyroid molecular imaging allows functional characterization of different thyroid diseases, even before clinical symptoms become manifest, and remains integral to the management of such conditions. Our present paper summarizes basic concepts, clinical applications, and potential developments of thyroid molecular imaging in patients affected by thyrotoxicosis and thyroid nodules.

Assessment of Treatment Response to Lenvatinib in Thyroid Cancer Monitored by F-18 FDG PET/CT Using PERCIST 1.0, Modified PERCIST and EORTC Criteria-Which One Is Most Suitable?

Background: We aimed to compare the established metabolic response criteria PERCIST and EORTC for their applicability and predictive value in terms of clinical response assessment early after the initiation of lenvatinib therapy in patients with metastatic radioiodine-refractory (RAI) thyroid cancer (TC). Methods: In 25 patients treated with lenvatinib, baseline and 4-month follow-up F-18 FDG PET/CT images were analyzed using PERCIST 1.0, modified PERCIST (using SUVpeak or SUVmax) and EORTC criteria. Two groups were defined: disease control (DC) and progressive disease (PD), which were correlated with PFS and OS. Results: PERCIST, mPERCIST, PERCISTmax and EORTC could be applied in 80%, 80%, 88% and 100% of the patients based on the requirements of lesion assessment criteria, respectively. With PERCIST, mPERCIST, PERCISTmax and EORTC, the patients classified as DC and PD ranged from 65 to 68% and from 32 to 35%, respectively. Patients with DC exhibited a longer median PFS than patients with PD for EORTC (p < 0.014) and for PERCIST and mPERCIST (p = 0.037), respectively. Conclusion: EORTC and the different PERCIST criteria performed equally regarding the identification of patients with PD requiring treatment changes. However, the applicability of PERCIST 1.0 using SULpeak seems restricted due to the significant proportion of small tumor lesions.

GLUT1 and ASCT2 Protein Expression in Papillary Thyroid Carcinoma Patients and Relation to Hepatitis C Virus: A Propensity-Score Matched Analysis

PURPOSE

Recently, glucose and amino acid transporters have gradually become a hot topic in thyroid gland biology and cancer research. We aimed to investigate the expressions of glucose transporter 1 (GLUT1) and glutamine transporter 2 (ASCT2) in papillary thyroid carcinoma (PTC) and their clinical significance and relation to HCV-related hepatitis.

PATIENTS AND METHODS

Screening 202 TC tissue samples against the selection criteria using a propensity-score matched analysis to adjust for age, sex, side of tumor, histopathological variants, TNM staging system, and the positivity for HCV yielded 51 matched (17 HCV positive and 34 HCV negative) PTC samples. The expressions of GLUT1 and ASCT2 expressions were detected by immunohistochemical staining. Kaplan-Meier survival curves were generated for disease-free and overall survival, and multivariate Cox regression analysis was applied to identify predictors for mortality.

RESULTS

Of 51 thyroid cancer tissues, 85% showed positive GLUT1 cytoplasmic staining, and 26% had a high expression score. All thyroid cancer specimens demonstrated ASCT2 cytoplasmic staining with membranous accentuation. Of these, 78% showed a high expression score, and 22% showed weak staining. On stratifying the study cohort based on the HCV status, HCV negative cohort showed a significantly higher immunoreactivity score for GLUT1 (p = 0.004) but not ASCT2 (p = 0.94) than HCV positive group. The expressions of the studied transporters showed no significant associations with the prognostic features of PTC nor the disease-free/overall survival.

CONCLUSION

GLUT1 and ASCT2 immunohistochemical staining showed positive expression with variable intensity in nearly 85% and 100% of PTC tissue samples compared to normal ones, respectively. Furthermore, GLUT1 protein expression, not ASCT2, showed a higher immunoreactivity score in PTC patients who are negative for HCV than cancer patients with positive HCV. Meanwhile, the expression of both protein markers was not associated with the clinicopathological characteristics of the studied PTC patients. Further large-scale multicenter studies are recommended to validate the present findings.

Metabolic Reprogramming of Thyroid Cancer Cells and Crosstalk in Their Microenvironment

Metabolism differs significantly between tumor and normal cells. Metabolic reprogramming in cancer cells and metabolic interplay in the tumor microenvironment (TME) are important for tumor formation and progression. Tumor cells show changes in both catabolism and anabolism. Altered aerobic glycolysis, known as the Warburg effect, is a well-recognized characteristic of tumor cell energy metabolism. Compared with normal cells, tumor cells consume more glucose and glutamine. The enhanced anabolism in tumor cells includes de novo lipid synthesis as well as protein and nucleic acid synthesis. Although these forms of energy supply are uneconomical, they are required for the functioning of cancer cells, including those in thyroid cancer (TC). Increasing attention has recently focused on alterations of the TME. Understanding the metabolic changes governing the intricate relationship between TC cells and the TME may provide novel ideas for the treatment of TC.

Metabolic Reprogramming in Thyroid Cancer: Role of the Epithelial-Mesenchymal Transition

Thyroid cancer (TC) represents the most common endocrine malignancy, with an increasing incidence all over the world. Papillary TC (PTC), a differentiated TC subtype, is the most common and, even though it has an excellent prognosis following radioiodine (RAI) ablation, it shows an aggressive behavior in 20–30% of cases, becoming RAI-resistant and/or metastatic. On the other side, anaplastic thyroid carcinoma (ATC), the most undifferentiated TC, is a rare but devastating disease, indicating that progression of differentiated to undifferentiated forms of TC could be responsible for RAI-resistance and increased mortality. The epithelial-to-mesenchymal transition (EMT) plays a pivotal role in both tumor progression and resistance to therapy. Moreover, during tumor progression, cancer cells modify their metabolism to meet changed requirements for cellular proliferation. Through these metabolic changes, cancer cells may adopt cancer stem cell-like properties and express an EMT phenotype. EMT, in turn, can induce metabolic changes to which cancer cells become addicted. Here we review metabolic reprogramming in TC highlighting the role of EMT with the aim to explore a potential field to find out new therapeutic strategies for advanced-stage PTC. Accordingly, we discuss the identification of the metabolic enzymes and metabolites, critical to TC progression, which can be employed either as predicting biomarkers of tumor response to RAI therapy or possible targets in precision medicine.

The Use of 18F-FDG PET/CT in Patients with Recurrent Differentiated Thyroid Cancer

Objectives:

¹⁸Fluorine-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) is used to monitor the recurrence in thyroid cancer patients when there is suspicion of metastases. De-differentiated lesions become ¹⁸F-FDG avid with a more aggressive clinical course. The aim of this study was to investigate the use of ¹⁸F-FDG PET/CT in differentiated thyroid cancer.

Methods:

Forty-six patients, either with a negative radioiodine scan or clinical progression and suspicions for metastases with differentiated thyroid cancer that were referred to our department for ¹⁸F-FDG PET/CT scan and evaluated retrospectively. PET/CT findings were correlated with clinical and histopathological findings, serum thyroglobulin (Tg), and anti-Tg levels.

Results:

Twenty-six patients (56.2%) were positive for recurrence in ¹⁸F-FDG PET/CT images. Positive ¹⁸F-FDG PET/CT findings were significantly correlated with the disease stage and Tg levels. Maximum standardized uptake value did not correlate with other findings or patients’ profiles. The cut-off value for Tg was at 52.5 ng/mL having 73.08% sensitivity, 75% specificity, 79.17% positive predictive value, and 68.18% negative predictive value for ¹⁸F-FDG PET/CT imaging.

Conclusion:

¹⁸F-FDG PET/CT is useful for detecting recurrence in differentiated thyroid cancer. Increased Tg levels and stage of the disease were significantly correlated with ¹⁸F-FDG positivity. ¹⁸F-FDG positivity may also provide information about the de-differentiation process that may support the treatment plan.

The Expression and Survival Significance of Glucose Transporter-1 in Pancreatic Cancer: Meta-Analysis, Bioinformatics Analysis and Retrospective Study

To explore the expression profile and prognostic relevance of GLUT-1 in pancreatic cancer, a meta-analysis, bioinformatics analysis based on Gene Expression Omnibus (GEO), Oncomine dataset and The Cancer Genome Atlas (TCGA) database, and immunohistochemistry in tumor and normal tissue from 88 pancreatic ductal adenocarcinoma (PDAC) patients were performed. GLUT-1 was significantly overexpressed in pancreatic cancer but it could not be a significant biomarker for prognosis. TNM stage and pathological grade could be biomarker of poor prognosis of patients with pancreatic cancer.

[18F]-FDG-PET/CT and [18F]-FAZA-PET/CT Hypoxia Imaging of Metastatic Thyroid Cancer: Association with Short-Term Progression After Radioiodine Therapy

PURPOSE

To examine the relationships between 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]-FDG) and hypoxia tracer [¹⁸F]fluoro-azomycinarabinofuranoside ([¹⁸F]-FAZA) and between ¹³¹I and [¹⁸F]-FAZA uptake in patients with metastatic thyroid cancer and to evaluate imaging features associated with short-term progression after ¹³¹I therapy.

PROCEDURES

The study population was 20 patients (17 women and 3 men; mean age, 67 years) with metastatic thyroid cancer who underwent both [¹⁸F]-FDG- and [¹⁸F]-FAZA-positron emission tomography (PET)/X-ray computed tomography (CT) examinations before ¹³¹I therapy. Short-term response to radioiodine was assessed (mean follow-up, 19 months ± 9). PET parameters including [¹⁸F]-FDG-SUVmax, [¹⁸F]-FAZA-SUVmax, and [¹⁸F]-FAZA-tumor-to-muscle [T/M] were obtained. Mann-Whitney U, Wilcoxon signed-rank, or χ² tests were used to assess differences between two quantitative variables or compare categorical data. Predictive factors for short-term progression were investigated with logistic regression analysis.

RESULTS

Eleven lymph node metastatic lesions were identified in 9 patients and 46 distant metastatic lesions (lung, 19; bone, 17; and liver, 10) in 14 patients. A total of 24 ¹³¹I-positive and 33 ¹³¹I-negative lesions were detected. SUVmax was significantly lower with [¹⁸F]-FAZA-PET/CT (1.3 ± 0.6) than with [¹⁸F]-FDG-PET/CT (6.4 ± 5.9, p < 0.001). No significant correlation was observed between [¹⁸F]-FAZA-PET/CT and ¹³¹I imaging concerning visibility (p = 0.36). After ¹³¹I therapy, 31 of 57 metastatic lesions displayed short-term progression. Multivariate logistic regression revealed that [¹⁸F]-FDG-SUVmax (p = 0.022) and [¹⁸F]-FAZA-T/M (p = 0.002) showed significant associations with short-term progression.

CONCLUSIONS

Although [¹⁸F]-FAZA uptake was low in metastatic thyroid cancers, not only glucose metabolism but also hypoxic conditions may be associated with progression after ¹³¹I therapy in patients with metastatic thyroid cancer.

Pieces of the Complex Puzzle of Cancer Cell Energy Metabolism: An Overview of Energy Metabolism and Alternatives for Targeted Cancer Therapy

Over the past decades, several advances in cancer cell biology have led to relevant details about a phenomenon called the 'Warburg effect'. Currently, it has been accepted that the Warburg effect is not compatible with all cancer cells, and thus the process of aerobic glycolysis is now challenged by the knowledge of a large number of cells presenting mitochondrial function. The energy metabolism of cancer cells is focused on the bioenergetic and biosynthetic pathways in order to meet the requirements of rapid proliferation. Changes in the metabolism of carbohydrates, amino acids and lipids have already been reported for cancer cells and this might play an important role in cancer progression. To the best of our knowledge, these changes are mainly attributed to genetic reprogramming which leads to the transformation of a healthy into a cancerous cell. Indeed, several enzymes that are highly relevant for cellular energy are targets of oncogenes (e.g. PI3K, HIF1, and Myc) and tumor suppressor proteins (e.g. p53). As a consequence of extensive studies on cancer cell metabolism, some new therapeutic strategies have appeared that aim to interrupt the aberrant metabolism, in addition to influencing genetic reprogramming in cancer cells. In this review, we present an overview of cancer cell metabolism (carbohydrate, amino acid, and lipid), and also describe oncogenes and tumor suppressors that directly affect the metabolism. We also discuss some of the potential therapeutic candidates which have been designed to target and disrupt the main driving forces associated with cancer cell metabolism and proliferation.

The diagnostic and predictive efficacy of 18F-FDG PET/CT metabolic parameters for EGFR mutation status in non-small-cell lung cancer: A meta-analysis

PURPOSE

To investigate the predictive performance of the maximum standardized uptake value (SUV_max) and mean standardized uptake value (SUV_mean) of primary lesions based on 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for EGFR mutation status in patients with non-small cell lung cancer (NSCLC).

METHODS

The PubMed/Medline, Embase, Cochrane Library and Web of Science databases were searched as of January 1, 2021. Studies whose reported data could be used to construct contingency tables were included. Study characteristics were extracted, and methodological quality assessment was conducted by two separate reviewers using the Quality Assessment of Diagnostic Accuracy Studies. The pooled sensitivity, specificity and area under the summary receiver operating characteristic curve (AUROC) were calculated. The possible causes of heterogeneity were analysed by meta-regression.

RESULTS

The 18 included studies had a total of 4024 patients. The majority of the studies showed a low to unclear risk of bias and concerns of applicability. For differentiating EGFR-mutant NSCLC from wild-type NSCLC, the pooled sensitivity and specificity were 71 % and 60 % for SUV_max and 64 % and 63 % for SUV_mean, respectively. The summary AUROCs of SUV_max and SUV_mean were 0.69 (95 % CI, 0.65-0.73) and 0.68 (95 % CI, 0.64-0.72), respectively. The meta-regression analysis indicated that blindness to EGFR mutation test results, the number of readers and the number of PET/CT scanners were possible causes of heterogeneity.

CONCLUSIONS

Our meta-analysis implied that SUV_max and SUV_mean of primary lesions from ¹⁸F-FDG PET/CT harboured moderate predictive efficacy for the EGFR mutation status of NSCLC.

PET/CT in the management of differentiated thyroid cancer

The standard treatment of differentiated thyroid cancer (DTC) consists of surgery followed by iodine-131 (¹³¹I) administration. Although the majority of DTC has a very good prognosis, more aggressive histologic subtypes convey a worse prognosis. Follow-up consists of periodically measurements of serum thyroglobulin, thyroglobulin antibodies and neck ultrasound and ¹²³I/¹³¹I whole-body scan. However, undifferentiated thyroid tumors have a lower avidity for radioiodine and the ability of DTC to concentrate ¹³¹I may be lost in metastatic disease. Positron emission tomography (PET)/computed tomography (CT) has been introduced in the evaluation of patients with thyroid tumors and the 2-[18F]-fluoro-2-deoxyd-glucose (¹⁸F-FDG) has been largely validated as marker of cell's metabolism. According to the 2015 American Thyroid Association guidelines, ¹⁸F-FDG PET/CT is recommended in the follow-up of high-risk patients with elevated serum thyroglobulin and negative ¹³¹I imaging, in the assessment of metastatic patients, for lesion detection and risk stratification and in predicting the response to therapy. It should be considered that well-differentiated iodine avid lesions could not concentrate ¹⁸F-FDG, and a reciprocal pattern of iodine and ¹⁸F-FDG uptake has been observed. Beyond ¹⁸F-FDG, other tracers are available for PET imaging of thyroid tumors, such as Iodine-124 (¹²⁴I), ¹⁸F-tetrafluoroborate and Gallium-68 prostate-specific membrane antigen. Moreover, the recent introduction of PET/MRI, offers now several opportunities in the field of patients with DTC. This review summarizes the evidences on the role of PET/CT in management of patients with DTC, focusing on potential applications and on elucidating some still debating points.

Data set for reporting carcinoma of the thyroid: recommendations from the International Collaboration on Cancer Reporting

Thyroid cancer therapy is increasingly tailored to patients' risk of recurrence and death, placing renewed importance on pathologic parameters. The International Collaboration on Cancer Reporting (ICCR), an organization promoting evidence-based, internationally agreed-upon standardized pathology data sets, is the ideal conduit for the development of a pathology reporting protocol aimed at improving the care of patients with thyroid carcinomas. An international expert panel reviewed each element of thyroid pathology reporting. Recommendations were made based on the most recent literature and expert opinion.The data set uses the most recent World Health Organization (WHO) classification for the purpose of a more clinically and prognostically relevant nomenclature. One example is the restriction of the term minimally invasive follicular carcinoma to tumors with capsular invasion only. It reinforces the already established criteria for blood vessel invasion adopted by the most recent WHO classification and Armed Forces Institute of Pathology fascicle. It emphasizes the importance of the extent of blood vessel invasion and extrathyroid extension to better stratify patients for appropriate therapy. It is the first data set that requires pathologists to use the more recently recognized prognostically powerful parameters of mitotic activity and tumor necrosis. It highlights the importance of assessing nodal disease volume in predicting the risk of recurrence.The ICCR thyroid data set provides the tools to generate a report that will guide patient treatment in a more rational manner aiming to prevent the undertreatment of threatening malignancies and spare patients with indolent tumors the morbidity of unnecessary therapy. We recommend its routine use internationally for reporting thyroid carcinoma histology.

Relationship between clinicopathologic factors and FDG avidity in radioiodine-negative recurrent or metastatic differentiated thyroid carcinoma

BACKGROUND

In this study, we investigated the relationship between clinicopathologic factors, BRAFV600E mutation status and [18F] F-fluoro-2-deoxyglucose (FDG) avidity in patients with radioiodine (RAI)-negative recurrent or metastatic differentiated thyroid cancer (DTC).

METHODS

From 2015 to 2018 all patients with suspected recurrent or metastatic radioiodine-negative DTC patients who underwent FDG positron emission tomography/computed tomography (PET/CT) were retrospectively reviewed. Suspected lesions on FDG PET/CT were biopsied and underwent BRAFV600E mutation testing by immunohistochemistry and real-time PCR. Tumor size, recurrent versus metastatic disease, histopathologic features including classical type versus aggressive subtypes (poorly differentiated, tall cell, columnar cell, hobnail variants) and BRAFV600E mutation status were correlated with the SUVmax of highest hypermetabolic lesions on FDG PET/CT by the univariate analysis using logistic regression.

RESULTS

Sixty-three consecutive patients, 55 (87.3%) female, with median age of 48 (range 17-81) were included. The majority of patients had BRAFV600E mutation and classical subtype, 55/63 (87.3%) and 45/63(71.4%), respectively. Thyroglobulin at the time of suspected recurrence was 262.7 ng/ml (range 16.3-1000) and patients received a median 3 prior RAI treatments. Fifty-four patients (85.7%) had local recurrence. The majority of patients 58/63 (92.1%) had FDG-avid disease on PET/CT. On univariate analysis, tumor size aggressive histopathologic types and distant metastasis are the significant factors for predicting FDG uptake, p = 0.04, p = 0.001 and p = 0.004 respectively. Although FDG uptake of BRAFV600E bearing recurrent/metastatic RAIR DTC lesions was higher than those without the mutation, the difference did not reach statistical significance, SUVmax of 7.11 versus 4.91, respectively, p = 0.2.

CONCLUSION

The majority of recurrent or metastatic RAI-negative DTC have BRAFV600E mutation and detectable disease on FDG PET/CT. FDG avidity of the recurrent or metastatic RAI-negative DTC is independently associated with the aggressive histopathologic features.

Physiological and Pathophysiological Roles of Ion Transporter-Mediated Metabolism in the Thyroid Gland and in Thyroid Cancer

Thyroid cancer is the most common type of endocrine tumor and has shown an increasing annual incidence, especially among women. Patients with thyroid cancer have a good prognosis, with a high five-year survival rate; however, the recurrence rate and disease status of thyroid cancer remain a burden for patients, which compels us to further elucidate the pathogenesis of this disease. Recently, ion transporters have gradually become a hot topic in the field of thyroid gland biology and cancer research. Additionally, alterations in the metabolic state of tumor cells and protein molecules have gradually become the focus of scientific research. This review focuses on the progress in understanding the physiological and pathophysiological roles of ion transporter-mediated metabolism in both the thyroid gland and thyroid cancer. We also hope to shed light on new targets for the treatment and prognosis of thyroid cancer.

A Novel Nanoproteomic Approach for the Identification of Molecular Targets Associated with Thyroid Tumors

A thyroid nodule is the most common presentation of thyroid cancer; thus, it is extremely important to differentiate benign from malignant nodules. Within malignant lesions, classification of a thyroid tumor is the primary step in the assessment of the prognosis and selection of treatment. Currently, fine-needle aspiration biopsy (FNAB) is the preoperative test most commonly used for the initial thyroid nodule diagnosis. However, due to some limitations of FNAB, different high-throughput “omics” approaches have emerged that could further support diagnosis based on histopathological patterns. In the present work, formalin-fixed paraffin-embedded (FFPE) tissue specimens from normal (non-neoplastic) thyroid (normal controls (NCs)), benign tumors (follicular thyroid adenomas (FTAs)), and some common types of well-differentiated thyroid carcinoma (follicular thyroid carcinomas (FTCs), conventional or classical papillary thyroid carcinomas (CV-PTCs), and the follicular variant of papillary thyroid carcinomas (FV-PTCs)) were analyzed. For the first time, FFPE thyroid samples were deparaffinized using an easy, fast, and non-toxic method. Protein extracts from thyroid tissue samples were analyzed using a nanoparticle-assisted proteomics approach combined with shotgun LC-MS/MS. The differentially regulated proteins found to be specific for the FTA, FTC, CV-PTC, and FV-PTC subtypes were analyzed with the bioinformatic tools STRING and PANTHER showing a profile of proteins implicated in the thyroid cancer metabolic reprogramming, cancer progression, and metastasis. These proteins represent a new source of potential molecular targets related to thyroid tumors.

The Utility of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Differentiated Thyroid Cancer Patients with Biochemical Recurrence and Negative Whole-Body Radioiodine Scintigraphy and Evaluation of the Possible Role of a Limited Regional Scan

Purpose of the Study

¹⁸F-Fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) is used in the management of recurrent differentiated thyroid cancer (DTC) patients presented with rising thyroglobulin (Tg) or anti-Tg antibody (Atg) levels and negative whole-body I-131 scan (WBS). We aimed to evaluate the utility of regional or limited PET/CT in a large population preset with variable Tg/(ATg) levels.

Materials and Methods

In a retrospective study, we analyzed 137 PET/CT done on DTC patients presented with raised Tg/Atg and negative WBS. Retrospective evaluation of other available clinical information was done.

Results

One hundred and thirty-seven patients aged 8-72 years (41 ± 17.7 years) were included in the study. Eighty-nine (64.9%) patients had positive findings on ¹⁸F-FDG PET-CT. It included thyroid bed recurrence, cervical, mediastinal lymphadenopathy, lung, and bone lesions. In addition, 36 patients had metabolically inactive lung nodules detected on CT. Serum Tg and female sex were the only predictors for a positive PET scan. In most (97.1%) of the patients, the disease was limited to the neck and thoracic region.

Conclusions

PET/CT is an excellent imaging modality for evaluating DTC patients presented with biochemical recurrence. It not only finds the disease in more than 80% of the patients but also detects distant metastatic disease, which precludes regional therapies. Lesions were noted mostly in the neck and thoracic region with very few distant skeletal metastases (4/137 patients). In most of the patients, routine vertex to mid-thigh imaging could be avoided.

Usefulness of PET-CT scan in recurrent thyroid cancer

The aim of this paper is to discuss the risk of recurrence in patients with differentiated thyroid cancer and emphasize the importance of risk-group stratification, early recurrence identification and application of new imaging modalities, what is the PET-CT. Moreover, follow-up of patients with thyroid carcinoma should be carried out by specialized teams throughout life. Therefore, interdisciplinary case discussions in tumor conferences may improve the use of multimodal therapy especially in patients with poorly differentiated thyroid carcinomas. After baseline follow-up, if there is a suspicion of thyroid carcinoma, early PET-CT should be used for early detection and appropriate planning. Fortunately, due to the good localization possibility, the PET-CT enables a focused surgical procedure with avoidance of an unnecessary tumor search and thereby a reduction of the risk of injury of neighboring structures which is a concern with reoperative neck surgery.

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.

Role of Thyroglobulin Doubling Time in Differentiated Thyroid Cancer and Its Relationship with Demographic-Histopathologic Risk Factors and 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Parameters

Background: Aim of this study was to investigate the relationship between thyroglobulin doubling time (TgDT) and basal risk factors and metabolic parameters derived from ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in differentiated thyroid cancer (DTC). Materials and Methods: An analysis of 95 DTC patients who had rising serum thyroglobulin (Tg) levels under levothyroxine (LT4) suppression after radioiodine therapy was made. TgDT was calculated for 28/95 patients. The relationship between TgDT and basal demographic and histopathologic risk factors, preablative Tg, and antithyroglobulin antibody (ATg) levels and metabolic parameters was analyzed. Results: In 28 patients (15M, 13F, mean age: 52.6 ± 17.6) that TgDT could be calculated, ¹⁸F-FDG PET/CT was positive in 12 patients. Median TgDT was lower in ¹⁸F-FDG PET/CT positive patients compared to the negative cases (p < 0.05). Patients with skeletal metastasis or local recurrence had a shorter DT compared to the patients with lung metastasis. TgDT was correlated with peak standardized uptake value (SUV_peak) (p < 0.05). Maximum standardized uptake value (SUV_max) was correlated with tumor size (p < 0.05) and mean standardized uptake value (SUV_mean) with tumor size and vascular invasion (p < 0.05). Median SUV_max and SUV_mean were higher in follicular cancer or poor histological variants of papillary DTC compared to papillary cancer classical variant patients Conclusion: TgDT may be predictive of a positive ¹⁸F-FDG PET/CT in DTC. Skeletal metastasis and local recurrence are related to shorter TgDT. Greater tumor size, vascular invasion, and follicular cancer or poor variants of papillary carcinoma are related with higher SUV_max and SUV_mean. Larger scale studies are needed to confirm results and to calculate a possible cutoff of TgDT for a positive ¹⁸F-FDG PET/CT study.

Head-to-head comparison of F-18 FDG PET/CT in radioidine refractory thyroid cancer patients with elevated versus suppressed TSH levels a pilot study

Introduction

To perform a head-to-head comparison of the uptake pattern of F-18 fluorodeoxyglucose in positron emission computed tomography (FDG PET/CT) in radioiodine refractory thyroid carcinomas (RAIR) in the same patient under elevated TSH levels (eTSH) and suppressed TSH levels (sTSH).

Methods

FDG PET/CT studies were performed under two conditions: levothyroxine intake (sTSH) and 30 days after hormonal withdrawal (eTSH). SUVmax values and the number of lesions detected (local recurrence and metastases in cervical and distant lymph nodes, lungs and bone) where blindly evaluated. Blood serum TSH and Tg levels were obtained prior to both studies. FDG PET/CT imaging, neck ultrasound, biopsy and follow-up were considered the reference standard.

Results

Fifteen patients performed both eTSH and sTSH FDG PET/CT studies. Both were positive for metastases in 80% of the patients. eTSH FDG PET/CT studies did not reveal increased uptake (p = 0.0640) and did not demonstrate a higher number of lesions (p = 0.320) when compared to sTSH FDG PET/CT studies. There was no change in the clinical management of these patients.

Conclusions

eTSH FDG PET/CT in patients with RAIR did not show more metastases in comparison to sTSH FDG PET/CT and there was no impact in clinical management of patients. Elevating TSH levels (whether by hormonal withdrawal or recombinant TSH) in patients being submitted to FDG PET/CT may not be necessary.

PFKFB4 negatively regulated the expression of histone acetyltransferase GCN5 to mediate the tumorigenesis of thyroid cancer

Thyroid cancer (TC) is the most common malignant endocrine tumor, and its incidence has progressively increased over several decades. Accumulating evidence has suggested that PFKFB4, a critical regulatory enzyme of glycolysis, has been implicated in various solid cancers. However, the exact effect of PFKFB4 on TC remains unclear. Hence, the objective of this work was to investigate the role of PFKFB4 in TC and explore the underlying regulatory mechanisms. Here, we provide evidence that mRNA levels of PFKFB4 were upregulated in TC patients' thyroids and cell lines. Downregulation of PFKFB4 reduced TC cell viability and inhibited colony formation. In addition, the migration and invasion of TC cells were suppressed by PFKFB4 knockdown, suggesting that PFKFB4 is positively correlated with tumorigenesis of TC. Molecularly, knockdown of PFKFB4 significantly inhibited expression of GCN5 and phosphorylation of PI3K/AKT. Moreover, the suppressive role of shPFKFB4 in TC cell growth was reversed by upregulation of GCN5. Finally, the in vivo experiment indicated that downregulation of PFKF4B suppressed tumor growth in xenografts TC model mice. In total, our results suggested that PFKFB4-mediated TC tumorigenesis by positively regulating GCN5 and PI3K/AKT signaling. These findings provide new research directions and therapeutic options considering PFKF4B as a novel diagnosis marker and therapeutic target.

Comprehensive gene expression analysis for exploring the association between glucose metabolism and differentiation of thyroid cancer

BACKGROUND

The principle of loss of iodine uptake and increased glucose metabolism according to dedifferentiation of thyroid cancer is clinically assessed by imaging. Though these biological properties are widely applied to appropriate iodine therapy, the understanding of the genomic background of this principle is still lacking. We investigated the association between glucose metabolism and differentiation in advanced thyroid cancer as well as papillary thyroid cancer (PTC).

METHODS

We used RNA sequencing of 505 patients with PTC obtained from the Cancer Genome Archives and microarray data of poorly-differentiated and anaplastic thyroid cancer (PDTC/ATC). The signatures of GLUT and glycolysis were estimated to assess glucose metabolic profiles. The glucose metabolic profiles were associated with tumor differentiation score (TDS) and BRAFV600E mutation status. In addition, survival analysis of glucose metabolic profiles was performed for predicting recurrence-free survival.

RESULTS

In PTC, the glycolysis signature was positively correlated with TDS, while the GLUT signature was inversely correlated with TDS. These correlations were significantly stronger in the BRAFV600E negative group than the positive group. Meanwhile, both GLUT and glycolysis signatures were negatively correlated with TDS in advanced thyroid cancer. The high glycolysis signature was significantly associated with poor prognosis in PTC in spite of high TDS. The glucose metabolic profiles are intricately associated with tumor differentiation in PTC and PDTC/ATC.

CONCLUSIONS

As glycolysis was an independent prognostic marker, we suggest that the glucose metabolism features of thyroid cancer could be another biological progression marker different from differentiation and provide clinical implications for risk stratification.

TRIAL REGISTRATION

Not applicable.

Glut 1 in Cancer Cells and the Inhibitory Action of Resveratrol as A Potential Therapeutic Strategy

An important hallmark in cancer cells is the increase in glucose uptake. GLUT1 is an important target in cancer treatment because cancer cells upregulate GLUT1, a membrane protein that facilitates the basal uptake of glucose in most cell types, to ensure the flux of sugar into metabolic pathways. The dysregulation of GLUT1 is associated with numerous disorders, including cancer and metabolic diseases. There are natural products emerging as a source for inhibitors of glucose uptake, and resveratrol is a molecule of natural origin with many properties that acts as antioxidant and antiproliferative in malignant cells. In the present review, we discuss how GLUT1 is involved in the general scheme of cancer cell metabolism, the mechanism of glucose transport, and the importance of GLUT1 structure to understand the inhibition process. Then, we review the current state-of-the-art of resveratrol and other natural products as GLUT1 inhibitors, focusing on those directed at treating different types of cancer. Targeting GLUT1 activity is a promising strategy for the development of drugs aimed at treating neoplastic growth.

Therapeutic Delivery of miR-143 Targeting Tumor Metabolism in Poorly Differentiated Thyroid Cancer Xenografts and Efficacy Evaluation Using 18F-FDG MicroPET-CT

Poorly differentiated thyroid carcinoma cells tend to be more aggressive and show enhanced glucose uptake which could be exploited for anti-cancer strategy. Previously, we identified hexokinase 2 (HK2) as a direct target of miR-143. In our current study, the effects of miR-143 on glucose metabolism and tumor biological behavior were investigated in FTC-133 cells which is a poorly differentiated thyroid carcinoma (PDTC). Additionally, tumor-bearing mice xenografts of PDTC were constructed, with encapsulated miR-143 agomir being administered intravenously. 18F-FDG microPET-CT scanning was used for the evaluation of therapeutic efficacy. The tumor-restrained effect of miR-143 was demonstrated in PDTC. Furthermore, microPET/CT imaging exhibited a reduction of 18F-FDG uptake in tumors, corresponding to the downregulated expression of HK2 in tissues. In summary, our results suggest that miR-143 can be an alternative treatment for PDTC and the specific assessment of therapeutic response to miR-143 can be achieved by 18F-FDG microPET/CT in advanced thyroid carcinoma xenografts.