Pre-Operative Calcitonin and CEA Values May Predict the Extent of Metastases to the Lateral Neck Lymph Nodes in Patients with Medullary Thyroid Cancer.

Background: In medullary thyroid cancer (MTC), lymph node metastases are often present at diagnosis and the extent of surgery is usually based upon pre-operative calcitonin and CEA levels as well as ultrasound findings. The aim of this study was to evaluate the role of pre-operative calcitonin and CEA levels as predictive markers of the burden of lymph node metastases at diagnosis. Methods: we conducted a retrospective study analyzing 87 MTC patients. Results: The median levels of calcitonin and CEA were 88.4 pg/mL and 7.0 ng/mL, respectively, in patients with no lymph nodes metastases; 108.0 pg/mL and 9.6 ng/mL, respectively, in patients with metastases to 1-5 lymph nodes; 520.5 pg/mL and 43.2 ng/mL, respectively, in patients with metastases to >5 lymph nodes. There were no significant differences in pre-operative calcitonin and CEA values between N0 and N1a patients, whereas they were significantly higher in N1b patients. Pre-operative cut-off levels distinguishing N0/N1a from N1b patients were 90 pg/mL for calcitonin (sensitivity 100%, specificity 59.3%, AUC = 0.82) and 17 ng/mL for CEA (sensitivity 100%, specificity 75%, AUC = 0.89). Conclusions: in patients with MTC, pre-operative serum calcitonin and CEA levels may drive the decision-making process to better define the extent of surgery.

Fluctuating obliterative bronchiolitis in RET-mutant medullary thyroid cancer patient treated with selpercatinib.

Highly selective RET inhibitor selpercatinib has demonstrated notable efficacy in advanced/progressive RET-mutant medullary thyroid cancer (MTC) patients. However, despite a more tolerable toxicity profile than multikinase inhibitors, peculiar adverse events (AEs) have been described. Obliterative bronchiolitis (OB) is a respiratory disease characterized by inflammation and fibrosis in small conducting airways. We evaluated a 70-year-old man with advanced RET-mutant MTC who developed OB during treatment with selpercatinib. Radiological features of OB occurred early and persisted during selpercatinib treatment, with a waxing and waning pattern. Notably, a partial response of MTC was achieved during the treatment, and selpercatinib was never reduced or interrupted. The almost complete absence of symptoms and the fluctuating trend, without specific treatment for OB, suggested that it is necessary to carefully evaluate the risks mediated by this AE with the risks of modifying or discontinuing the anti-cancer therapy.

Minor role of TP53 and TERT promoter mutations in medullary thyroid carcinoma: report of new cases and revision of the literature.

PURPOSE: Aims of this study were to investigate the prevalence of TP53 and TERT mutations in Medullary Thyroid carcinoma (MTC) and their role in inducing aggressiveness in positive cases. METHODS: We performed a literature search in PubMed to identify studies investigating the prevalence of TERT and TP53 mutations in MTC. We also included data on MTC cases (n = 193) obtained at our center and unpublished. The in-silico pathogenicity of the TP53 mutations has been evaluated by predictor tools. RESULTS: We identified a total of 25 and 11 published papers: all together 1280 cases have been investigated for the presence of TP53 mutations and 974 for TERT promoter mutation. Twenty-five out of 1280 (2%) cases had a TP53 mutation while only 3/974 MTC cases (0.3%) have been found to be positive for TERT promoter mutations. Among all, we identified 19 different TP53 mutations that in 12 cases were demonstrated to have an in silico predicted high pathogenic role and a high impact on protein function. Three non-sense and 4 probably not damaging mutations were also reported. The pathogenic role of the TERT promoter mutations has been previously in vitro determined. No correlation between TP53 and/or TERT mutations and aggressiveness of MTC has been demonstrated. CONCLUSION: The prevalence of TP53 and TERT promoter mutations is very low in MTC. The reported mutations are pathogenic in the majority of cases. Because of their rarity it is not possible to clarify if they play or not a role in the pathogenesis and/or aggressiveness of this specific thyroid tumor.

Medullary Thyroid Carcinoma: A Unique Case Report.

Medullary thyroid carcinoma is a rare neuroendocrine tumor derived from parafollicular C-cells. It can be inherited as part of syndromes, such as familial medullary thyroid cancer (FMTC) and multiple endocrine neoplasia type 2 (MEN 2), or it can arise sporadically. We herein report a unique case of medullary thyroid carcinoma in a 50-year-old male who presented with a neck mass. Fine needle aspiration cytology (FNAC) of the thyroid and histopathological examination revealed a diagnosis of medullary thyroid carcinoma. Both carcinoembryonic antigen (CEA) and calcitonin are the key serum markers utilized in the diagnosis and monitoring of medullary thyroid cancer (MTC). Thorough evaluation, prompt identification, and efficient treatment constitute the pivotal measures for ensuring favorable survival outcomes.

Diagnostic Performance of Preoperative Calcitonin and Procalcitonin Tests for Differential Diagnosis of Medullary Thyroid Cancer.

Medullary thyroid cancer (MTC) shows a relatively poor prognosis among thyroid cancers. Though calcitonin has been used as a diagnostic marker for MTC, it has disadvantages including poor sample stability and discrepancies among results by assay. This study aimed to compare the usefulness of preoperative calcitonin and procalcitonin (PCT) in the diagnosis of MTC. Serum calcitonin and PCT levels were measured before thyroidectomy from MTC (n = 23) and other types of thyroid cancers in patients (n = 1308). Diagnostic performances of calcitonin and PCT for discerning MTC were estimated. In a multivariate analysis, preoperative calcitonin level was independently associated with the diagnosis of MTC, whereas PCT was not. Calcitonin and PCT, respectively, exhibited area under the curve values of 0.997 and 0.979 for the diagnosis of MTC, without significant differences. For calcitonin, the sensitivity, specificity, and positive and negative predictive values were 0.957, 0.992, 0.688, and 0.999, respectively, at a cut-off of 7.2 pg/mL. The corresponding values for PCT were 0.913, 0.995, 0.778, and 0.998 at a cut-off of 0.19 ng/mL. Preoperative calcitonin and PCT showed similar diagnostic utility for MTC. Depending on the patient's clinical status and laboratory environment, these tests can be used as complementary methods for detecting MTC.

Biomarker identification of medullary thyroid carcinoma from gene expression profiles considering without-treatment and with-treatment studies-A bioinformatics approach.

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor derived from parafollicular thyroid gland cells. In both hereditary MTC and sporadic forms, genetic changes result in fundamental changes, and prognosis and mutational status are highly correlated. In this work, biomarker genes (DEGs and DEmiRNAs) for MTC will be computationally identified in order to help in their diagnosis and treatment. The gene expression profiles of two different types of studies, namely without-treatment (wo-trt) and with-treatment (w-trt), are considered for discovering biomarkers. The datasets were retrieved from the GEO database, and the DEGs and DEmiRNAs were analyzed using ExpressAnalyst and GEO2R. The functional analysis of DEGs and DEmiRNAs was performed, and most of the pathways enriched related to thyroid oncological pathways such as MAPK pathway,mTOR pathway, and PI3K-AKT Signaling pathway. Through this conclusion, the RET gene was upregulated wo-trt; the dinaciclib treatment RET gene was down-regulated computationally. To optimize the therapeutic targeting of RET, greater research into the mechanisms regulating RET transcription is necessary.

Well-defined survival outcome disparity across age cutoffs at 45 and 60 for medullary thyroid carcinoma: a long-term retrospective cohort study of 3601 patients.

Background: Medullary thyroid cancer (MTC) is a challenging malignancy. The survival outcome of MTC based on AJCC staging system does not render a discriminant classifier among early stages. Methods: 3601 MTC patients from 2000 to 2018 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Smooth curve fitting, Cox proportional hazard regression and competing risk analysis were applied. Results: A linear correlation between age and log RR (relative risk of overall death) was detected. Overlaps were observed between K-M curves representing patients aged 45-50, 50-55, and 55-60. The study cohort was divided into 3 subgroups with 2 age cutoffs set at 45 and 60. Each further advanced age cutoff population resulted in a roughly "5%" increase in MTC-specific death risks and an approximately "3 times" increase in non-MTC-specific death risks. Conclusions: The survival outcome disparity across age cutoffs at 45 and 60 for MTC has been well defined.

Medullary Thyroid Cancer: Molecular Drivers and Immune Cellular Milieu of the Tumour Microenvironment-Implications for Systemic Treatment.

In this review, we explore the underlying molecular biology of medullary thyroid carcinoma (MTC) and its interplay with the host immune system. MTC is consistently driven by a small number of specific pathogenic variants, beyond which few additional genetic events are required for tumorigenesis. This explains the exceedingly low tumour mutational burden seen in most MTC, in contrast to other cancers. However, because of the low tumour mutational burden (TMB), there is a correspondingly low level of tumour-associated neoantigens that are presented to the host immune system. This reduces tumour visibility and vigour of the anti-tumour immune response and suggests the efficacy of immunotherapy in MTC is likely to be poor, acknowledging this inference is largely based on the extrapolation of data from other tumour types. The dominance of specific RET (REarranged during Transfection) pathogenic variants in MTC tumorigenesis rationalizes the observed efficacy of the targeted RET-specific tyrosine kinase inhibitors (TKIs) in comparison to multi-kinase inhibitors (MKIs). Therapeutic durability of pathway inhibitors is an ongoing research focus. It may be limited by the selection pressure TKI treatment creates, promoting survival of resistant tumour cell clones that can escape pathway inhibition through binding-site mutations, activation of alternate pathways, and modulation of the cellular and cytokine milieu of the tumour microenvironment (TME).

Digoxin treatment does not reinduce radioiodine uptake in radioiodine refractory non-medullary thyroid carcinoma.

Objective: Patients with non-medullary thyroid carcinoma (NMTC) that are refractory to radioactive iodine (RAI) have a poor prognosis. Strategies for restoring the ability to take up iodine, so-called redifferentiation, are promising but not suitable for all patients. Preclinical studies, in human cell lines just as in a murine model, have shown that the cardiac glycoside digoxin restored RAI uptake. This prospective single-center open-label study aimed to investigate whether treatment with digoxin could reinduce clinically relevant RAI uptake in patients with metastasized RAI-refractory NMTC. Methods: Eight patients with metastasized RAI-refractory NMTC were included between November 2022 and June 2023. Before treatment, a baseline [123I]NaI scintigraphy was performed. Thereafter, patients were treated with digoxin for 3 weeks. Starting doses depended on age and weight. For safety reasons, the usual therapeutic range was aimed for. After 1 week, the digoxin plasma concentration was measured, and the digoxin dose was adjusted if necessary. After 3 weeks of digoxin treatment, a second [123I]NaI scintigraphy was performed. RAI uptake was compared between the two scintigraphies. Results: Seven patients completed the digoxin treatment and were evaluable. None of the seven patients showed clinically relevant RAI uptake after digoxin treatment. No digoxin-related serious adverse events occurred during this trial. Conclusion: Contrary to results from preclinical trials, in this trial, 3 weeks of digoxin treatment did not reinduce RAI uptake in patients with NMTC. This highlights essential challenges regarding the approach toward optimization of studies aimed to restore the RAI uptake and its therapeutic efficacy through drug repurposing.

The Multi-Institutional Medullary Thyroid Cancer Collaborative Registry: Can a Rare Tumor Registry Accurately Represent the Real-World Patient Population?

Background: Large population-based registries, such as the Surveillance, Epidemiology and End Results (SEER) Registry, help in the study of rare tumors, including medullary thyroid cancer (MTC), but lack data to understand the natural history of the disease. The Medullary Thyroid Cancer Collaborative Registry (MTCCoRe) is an exhaustive multi-institutional collection of demographic, clinical, and pathological data. To determine the extent to which MTCCoRe represents the real-world MTC population, we compared the characteristics of patients enrolled in MTCCoRe with patients enrolled in population-based cancer registries. Methods: Comparison of demographic and clinical characteristics of MTC patients who were enrolled in MTCCoRe, Texas Cancer Registry (TCR), California Cancer Registry (CCR), and SEER between 1995 and 2018. Results: A total of 1416 patients were identified in MTCCoRe, 329 in TCR, 2105 in CCR, and 3820 in SEER. Percentages of patients 20-54 years in MTCCoRe were 58.0%, 50.2% in TCR, 47.2% in CCR, and 44.8% in SEER (p < 0.0001). About half of the patients were female (55.9% in MTCCoRe, 61.4% in TCR, 59% in CCR, and 57.5% in SEER (p = 0.3). Percentages of Hispanic and Black patients differed among cohorts (10.1% and 3.8% for MTCCoRe, 23.7% and 8.2% for TCR, 24.8% and 4.9% in CCR, and 15.9% and 8.2% for SEER, respectively; p < 0.001). MTCCoRe patients presented with more advanced T and N classifications than patients in the other registries (MTCCoRe, 28.6% T3-4 and 49.4% N1; TCR, 12.7% and 32.2%; CCR, 18.6% and 32.4%; and SEER, 24% and 37.8%; p < 0.0001). Prevalence of M1 disease was 10% in MTCCoRe, 11.9% in TCR, 14.1% in CCR, and 9.5% in SEER (p < 0.0001). In the MTCCoRe, 11.4% underwent systemic therapy (compared with 0.3% in TCR and 5.6% in CCR). Conclusions: The clinicodemographic profile of patients with MTC enrolled in a multi-institutional registry differs from those enrolled in population-based databases, with lower proportions of Hispanic and Black patients but additive data on treatment modalities. Moving forward, MTCCoRe and other registry and clinical trial enrollment efforts should intentionally include underrepresented groups via community engagement techniques, patient stakeholder involvement, and inclusion of languages other than English in study materials to yield more generalizable results and conclusions.

The impact of preoperative calcitonin screening on the prognosis of patients with medullary thyroid cancer: a retrospective multicenter cohort study.

PURPOSE: There is still controversy in different guidelines regarding the necessity of routine preoperative calcitonin (Ctn) testing in medullary thyroid cancer (MTC). The level of preoperative Ctn may influence the extent of surgery. METHODS: This retrospective multicenter cohort study involved 149 MTC patients from 6 centers between 2013 to 2023. Clinical characteristics, surgical procedure and clinical outcomes were compared between Ctn-screened and Non-screened group. Kaplan-Meier method was used to estimate recurrence-free survival (RFS) and overall survival (OS). RESULTS: In total, 127 MTC patients with preoperative Ctn screening and 22 MTC patients without screening were analyzed. MTC patients with preoperative Ctn screening underwent more radical surgical procedures including total thyroidectomy and lymph node dissection, compared to those without screening (84.3% vs. 68.2% and 91.3% vs. 72.7%, respectively). The rate of recurrence and death were lower in the Ctn-screened group (16.1% vs. 36.4%, 0.8% vs. 18.2%, respectively). The survival curve showed a significantly better overall survival in Ctn-screened group than Non-screened group (HR:17.932, 95% CI 1.888-170.294, p-value = 0.001), while no significant difference was observed of RFS between two groups (HR:1.6, 95% CI 0.645-3.966, p-value = 0.307). CONCLUSION: Preoperative Ctn screening can prompt surgeons choosing more radical initial surgical treatment for MTC patients, potentially leading to better long-term outcomes. Further evaluation of the cost-effectiveness of routine Ctn screening in thyroid nodule patients is warranted.

The role of [18F]F-DOPA PET/CT in diagnostic and prognostic assessment of medullary thyroid cancer: a 15-year experience with 109 patients.

Objective: Correct diagnosis and prognostic evaluation of medullary thyroid cancer (MTC) are crucial to treat patients. The purpose of this study was to evaluate the diagnostic and prognostic value of [18F]F-DOPA PET/CT in patients with MTC. Methods: We reviewed MTC patients who underwent [18F]F-DOPA PET/CT from June 2008 to November 2023. Clinical characteristics, follow-up data, and the following [18F]F-DOPA PET/CT parameters were recorded: maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume (MTV), and SUVmean of multiple organs. The diagnostic value of PET/CT for the detection of tumor lesions was calculated. Serum basal calcitonin (bCt) and stimulated calcitonin (sCt) were determined. Receiver operating characteristics, Kaplan-Meier, and Cox regression analyses were performed. Results: In total, 109 patients (50 women, 59 men; average age, 55 ± 14 years) were included in the analysis. The patient-related sensitivity, specificity, and accuracy of [18F]F-DOPA PET/CT were 95%, 93%, and 94%, respectively. The lesion-related sensitivity, specificity, and accuracy were 65%, 99%, and 72%, respectively. The optimal cutoff values of bCt, sCt, and CEA to obtain positive [18F]F-DOPA PET/CT results were 64 pg/mL, 1808 pg/mL, and 4 µg/L, respectively. Patients with negative [18F]F-DOPA PET/CT had longer overall survival than patients with positive [18F]F-DOPA PET/CT results (P = 0.017). Significant positive correlations were found between bCt, sCt, and CEA with SUVmax, SUVmean, and MTV of [18F]F-DOPA PET/CT (P < 0.001). [18F]F-DOPA PET/CT results and MTV may be useful for the evaluation of the prognosis of patients with recurrent MTC, while age and MTV were independent prognostic factors in patients with primary MTC. For all patients, SUVmean of the left kidney, liver, aorta, and pancreas might be used to independently predict OS. Conclusion: [18F]F-DOPA PET/CT had great value for diagnosis and prognostic assessment in patients with MTC. The DOPA PET/CT parameter SUVmean and MTV showed significant association with OS.

Primary resistance to selpercatinib in a patient with advanced medullary thyroid cancer.

Selpercatinib, a selective RET kinase inhibitor, has demonstrated remarkable efficacy in treating patients with advanced medullary (MTC) and differentiated thyroid cancer with RET alterations. Primary resistance to selpercatinib is a very uncommon situation, and its underlying mechanisms are poorly understood. We report the case of a 42-year-old female with advanced MTC harboring a somatic M918T RET mutation who exhibited a primary resistance to selpercatinib. Despite prompt treatment initiation after the diagnosis of progressive disease, the patient continued experiencing rapid spread of disease, characterized by the appearance of new metastatic lesions and increased tumor burden. Genomic analysis revealed no additional mutations associated with on-target or off-target resistance. This case highlights a rare clinical scenario of primary resistance to selpercatinib in advanced MTC. While secondary resistance mechanisms have been well-documented, primary resistance remains poorly understood. Possible explanations include tumor heterogeneity and activation of alternative signaling pathways that stills need to be elucidated. Emerging therapies targeting resistance mechanisms and next-generation RET inhibitors offer promising avenues for further investigation.

Patient-reported outcomes with selpercatinib treatment in patients with RET-driven cancers in the phase I/II LIBRETTO-001 trial.

BACKGROUND: This post-hoc retrospective study describes long-term patient-reported outcomes (PROs) for REarranged during Transfection (RET)-altered non-small-cell lung cancer (NSCLC), medullary thyroid cancer (MTC), non-MTC thyroid cancer (TC), and tumor agnostic (TA) patients (Data cut-off: January 2023) from the LIBRETTO-001 trial. PATIENTS AND METHODS: Patients completed the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ-C30). Patients with MTC also completed a modified version of the Systemic Therapy-Induced Diarrhea Assessment Tool (mSTIDAT). The proportion of patients with improved, stable, or worsened status after baseline was reported. PROs were summarized at 3 years (cycle 37) post-baseline for the NSCLC and MTC cohorts, and at 2 years (cycle 25) post-baseline for the TC and TA cohorts. Time-to-event outcomes (time to first improvement or worsening and duration of improvement) were reported. RESULTS: The baseline assessment was completed by 200 (63.3%), 209 (70.8%), 50 (76.9%), and 38 (73.1%) patients in the NSCLC, MTC, TC, and TA cohorts, respectively. The total compliance rate was 80%, 82%, 70%, and 85%, respectively. Approximately 75% (NSCLC), 81% (MTC), 75% (TC), and 40% (TA) of patients across all cohorts reported improved or stable QLQ-C30 scores at year 3 (NSCLC and MTC) or year 2 (TC and TA) with continuous selpercatinib use. Across cohorts, the median time to first improvement ranged from 2.0 to 19.4 months, the median duration of improvement ranged from 1.9 to 28.2 months, and the median time to first worsening ranged from 5.6 to 44.2 months. The total compliance rate for the mSTIDAT was 83.7% and the proportion of patients with MTC who reported diarrhea on the mSTIDAT was reduced from 80.8% at baseline to 35.6% at year 3. CONCLUSIONS: A majority of patients with RET-driven cancers improved or remained stable on most QLQ-C30 domains, demonstrating favorable health-related quality of life as measured by the QLQ-C30 during long-term treatment with selpercatinib.

Medullary Thyroid Cancer: Epidemiology and Characteristics According to Data From the Marne-Ardennes Register 1975-2018.

Context: Medullary thyroid cancer (MTC) is a rare disease. Objective: The main objective of our study was to analyze the incidence evolution of MTC with a follow-up of more than 40 years. Further, a descriptive and survival analysis was performed according to the Kaplan-Meier analysis. Design Setting and Patients: This is a retrospective epidemiological study using data from the Marne-Ardennes registry from 1975 to 2018. Two hundred sixty patients with MTC were included. Main Outcome Measures: The incidence was calculated in the territory of the register (Marne and Ardennes departments of France) and standardized on the demographic structure of France. Patient and tumor characteristics were described. An analysis in a subgroup comparing hereditary and sporadic forms was performed. An analysis of survival was performed. Results: The standardized incidence shows an increasing trend over time. The incidence increased significantly from 0.41 to 0.57/100 000 person-years between 1986 and 1996 and 2008 and 2018. The MTC was hereditary in 21.2% of cases. The sex ratio (males:females) was 0.73. The average age at diagnosis was 53 years. Ninety-seven patients (37.3%) were N1, 26 (10%) were M1, and 56 (21.5%) developed metastases during the follow-up. Complete remission was obtained in 58.5% of patients. The disease was refractory for 18.1% of patients. The 5-year survival rate was 88.4%. Sporadic cases had a poorer prognosis than hereditary MTC. Conclusion: Our study demonstrates a moderate increase in the incidence of MTC between 1975 and 2018. The prognosis remains worse for sporadic MTC than for hereditary MTC.

Medullary Thyroid Cancer: Single Institute Experience over Three Decades and Risk Factors for Recurrence.

CONTEXT: Medullary thyroid cancer has a historic recurrence rate up to 50%, and surgery remains the only cure. OBJECTIVE: This study aims to assess factors related to recurrence and metastatic spread in MTC. DESIGN: Retrospective chart review was performed from 1990-2023. Descriptive analysis and regression models were used for analysis. SETTING: Single specialized tertiary care referral center. PATIENTS: 68 patients with MTC, who underwent surgery, were included. MAIN OUTCOME MEASURE: Recurrence. RESULTS: Mean age at diagnosis was 54.9years(42.2-64.1), 65%(n=44) females. Lymph node and distant metastases were found in 24%(n=16) and 4%(n=3), respectively. RET mutations were present in 52%(n=35): MTC risk levels Highest 6%, High 7%, and Moderate 39%. Mean tumor size was 1.9cm(1.2-3.2) and mean preoperative calcitonin was 504.4pg/mL(133.2-1833.8). Total thyroidectomy(TT) was performed in 10 patients, TT+central neck dissection(CND) in 28, and TT+CND+lateral neck dissection(LND) in 25. On final pathology, 40% had positive central nodes and 25% had positive lateral nodes. Recurrence was 22%, median follow-up 4.7years(1.2-28.0). Male gender(HR=5.81, p=0.021), positive lateral neck nodes(HR 8.10, p=0.011) and high/highest MTC risk level RET mutations(HR 8.66, p=0.004) were significantly associated with recurrence. Preoperative calcitonin>2,175 pg/mL was a strong predictor for distant metastasis(AUC0.893) and a good predictor for lateral neck disease(AUC0.706). Extent of surgery was not significantly associated with recurrence(p=0.634). CONCLUSION: One of 4 patients undergoing surgery for MTC will recur. Risk factors associated with recurrence are male gender, lateral LN metastasis and high/highest MTC risk level mutations, but not necessarily surgery type. Preoperative calcitonin>2,175 pg/mL is suggestive of advanced disease and should prompt further evaluation.

In Vitro Effects of Boric Acid on Cell Cycle, Apoptosis, and miRNAs in Medullary Thyroid Cancer Cells.

Medullary thyroid cancer (MTC) is a highly aggressive and chemotherapy-resistant cancer originating from the thyroid's parafollicular C cells. Due to its resistance to conventional treatments, alternative therapies such as boric acid have been explored. Boric acid, a boron-based compound, has shown anticarcinogenic effects, positioning it as a potential treatment option for MTC. TT medullary thyroid carcinoma cell line (TT cells) and human thyroid fibroblast (HThF cells) were utilized for the cell culture experiments. Cell viability was assessed using the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay. Total RNA was extracted using Trizol reagent for gene expression and microRNA (miRNA) analysis via reverse transcription-polymerase chain reaction (RT-PCR). The extent of apoptosis induced by boric acid was determined using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Colony formation assays were conducted to evaluate the impact of boric acid on the colony-forming ability of MTC cells. At 48 h, 50% inhibitory concentration (IC50) of boric acid was found to be 35 µM. Treatment with boric acid resulted in significant modulation of apoptosis-related genes and miRNAs, including increased expression of phorbol-12-myristate-13-acetate-induced protein 1(NOXA), apoptotic protease activating factor 1 (APAF-1), Bcl-2-associated X protein (Bax), caspase-3, and caspase-9. In contrast, the expression of B cell lymphoma 2 (Bcl2), B cell lymphoma- extra-large (Bcl-xl), and microRNA-21 (miR-21), which are linked to the aggressiveness of MTC, was significantly reduced. The TUNEL assay indicated a 14% apoptosis rate, and there was a 67.9% reduction in colony formation, as shown by the colony formation assay. Our study suggests that boric acid may have anticancer activity in MTC by modulating apoptotic pathways. These findings suggest that boric acid could be a potential therapeutic agent for MTC and possibly for other malignancies with similar pathogenic mechanisms.

Developing Dynamic Structure-Based Pharmacophore and ML-Trained QSAR Models for the Discovery of Novel Resistance-Free RET Tyrosine Kinase Inhibitors Through Extensive MD Trajectories and NRI Analysis.

Activation of RET tyrosine kinase plays a critical role in the pathogenesis of various cancers, including non-small cell lung cancer, papillary thyroid cancers, multiple endocrine neoplasia type 2A and 2B (MEN2A, MEN2B), and familial medullary thyroid cancer. Gene fusions and point mutations in the RET proto-oncogene result in constitutive activation of RET signaling pathways. Consequently, developing effective inhibitors to target RET is of utmost importance. Small molecules have shown promise as inhibitors by binding to the kinase domain of RET and blocking its enzymatic activity. However, the emergence of resistance due to single amino acid changes poses a significant challenge. In this study, a structure-based dynamic pharmacophore-driven approach using E-pharmacophore modeling from molecular dynamics trajectories is proposed to select low-energy favorable hypotheses, and ML-trained QSAR models to predict pIC50 values of compounds. For this aim, extensive small molecule libraries were screened using developed ligand-based models, and potent compounds that are capable of inhibiting RET activation were proposed.

RET gene fusion and emergent Selpercatinib resistance in a calcitonin-rich neuroendocrine carcinoma: a case report.

Metastatic lung neuroendocrine carcinomas provide diagnostic challenges in identifying the cell of origin. High level calcitonin expression is not pathognomonic for medullary thyroid cancer. Tumor mutation analysis may provide essential clues regarding tissue origin and treatment targets. Oncogenic RET gene fusions have been identified in non-small cell lung cancer and non-medullary thyroid cancers, whereas RET point mutations are the key genetic finding in both inherited and sporadic MTC. Patients who receive radiation for the treatment of other cancers have an increased risk of developing a second malignancy, including a neuroendocrine carcinoma. Herein, we present a case of calcitonin-rich neuroendocrine carcinoma emerging on a background of prior radiation and chemotherapy for the treatment of Hodgkin's disease. Identification of a RET gene rearrangement (KIF5B-RET) led to initial successful treatment with selpercatinib, with eventual resistance associated with an activating mutation involving the MEK1 protein (MAP2K1 p. E102-I103 del) that led to relapse and progression of the disease.

Latest Progress in Risk-Adapted Surgery for Medullary Thyroid Cancer.

(1) Background: The wider adoption of a preoperative ultrasound and calcitonin screening complemented by an intraoperative frozen section has increased the number of patients with occult sporadic medullary thyroid cancer (MTC). These advances offer new opportunities to reduce the extent of the initial operations, minimizing operative morbidity and the risk of postoperative thyroxin supplementation without compromising the cure. (2) Methods: This systematic review of the international literature published in the English language provides a comprehensive update on the latest progress made in the risk-adapted surgery for sporadic and hereditary MTC guided by an intraoperative frozen section. (3) Results: The current evidence confirms the viability of a hemithyroidectomy for desmoplasia-negative sporadic MTC. To add an extra safety margin, the hemithyroidectomy may be complemented by a diagnostic ipsilateral central node dissection. Despite the limited extent of the surgery, all the patients with desmoplasia-negative sporadic tumors achieved a biochemical cure with excellent clinical outcomes. A hemithyroidectomy decreases the need for postoperative thyroxine substitution, but a total thyroidectomy may be required for bilateral nodular thyroid disease. Hereditary MTC is a different issue. Because each residual thyroid C cell carries its own risk of malignant progression, a total thyroidectomy remains mandatory for hereditary MTC. (4) Conclusion: In experienced hands, a hemithyroidectomy, which minimizes morbidity without compromising the cure, is an adequate therapy for desmoplasia-negative sporadic MTC.