The ocrelizumab wearing-off phenomenon is associated with reduced immunomodulatory response and increased neuroaxonal damage in multiple sclerosis.

OBJECTIVE: The wearing-off phenomenon is common in people with multiple sclerosis (MS) treated with ocrelizumab. We aim to evaluate the presence and severity of wearing-off to ocrelizumab in relation to demographic and MS clinical variables, immune profiling, and a marker of neuroaxonal damage (plasma neurofilament light chain (pNfl)). METHODS: This cross-sectional study included MS patients treated with ocrelizumab from at least 1 year. Wearing-off questionnaire and blood samples were collected between 21 and 23 weeks after the previous ocrelizumab infusion. Lymphocyte subpopulations were evaluated on peripheral blood using flow cytometry. PNfl was evaluated using fully automated chemiluminescent enzyme immunoassay. RESULTS: We included 106 people with MS (age 49.5 ± 11.6 years; females 42.3%; wearing-off 57.6%). On regression models, wearing-off was associated with higher pNfl, CD8, CD3, and CD3CD27 lymphocytes. Most frequent wearing-off symptoms were cognitive, sensory, and balance problems; wearing-off started < 1 week (9.4%), 1-4 weeks (10.7%) or > 4 weeks (10.7%) before infusion; 44.8% of the complaints were moderate to severe. Severity of wearing-off was associated with higher pNfl and CD8 lymphocytes. CONCLUSIONS: Wearing-off is common in people with MS treated with ocrelizumab, and is associated with reduced immunomodulation (higher T lymphocytes) and increased neuroaxonal damage, suggesting reduced treatment response.

Serum (-2)proPSA/freePSAratio, (-2)proPSA/freePSA density, prostate health index, and prostate health index density as clues to reveal postoperative clinically significant prostate cancer in men with prostate-specific antigen 2-10 ng/mL.

BACKGROUND: There is a strong clinical need to fill the gap of identifying clinically significant prostate cancer (csPCa) in men with prostate-specific antigen (PSA) gray zone values. Promising, but not definitive results have been obtained using PSA derivatives such as prostate health index (PHI) and PHI density (PHID) and the percentage (-2)proPSA/free PSA (%p2PSA/fPSA). Thus, this study aimed to compare the diagnostic value of PHI, PHID, %proPSA/fPSA, and (-2)proPSA/freePSA density (-2pPSA/fPSAD) for csPCa in the patients with PSA within 2-10 ng/mL. METHODS: Serum samples and clinicopathological features were prospectively collected from 142 patients who underwent robot-assisted radical prostatectomy  between September 2021 and December 2023. According to the inclusion criteria, the patients with total PSA  within 2 and 10 ng/mL and negative or suspicious digital rectal examination  were enrolled. We used two different classifications for csPCa: 1) patients with Gleason score (GS) ≥ 7(4 + 3) and 2) patients with GS ≥ 7(3 + 4). The receiver operating characteristic curves and the area under the curve (AUC) values were used to assess the diagnostic performance. RESULTS: Of the 142 men included, 116 (82%) patients were diagnosed with csPCa as GS ≥ 3 + 4 and 107 (75%) defined as csPCa as GS ≥ 7(4 + 3), respectively. We found that p2PSA/fPSA, p2PSA/fPSAD, PHI, and PHID were significantly higher in csPCa classified as GS ≥ 7(3 + 4) as well as GS ≥ 7(4 + 3), with p-values 0.027, 0.054, 0.0016, and 0.0027, respectively. AUCs of the analyzed variables were higher when used to predict csPCa as GS ≥ 6 compared to csPCa as GS ≥7(4 + 3), with an AUC equal, respectively, to 0.679 (95% CI: 0.571-0.786), 0.685 (95% CI: 0.571-0.799), 0.737 (95% CI: 0.639-0.836), and 0.736 (95% CI: 0.630-0.841) in the first subgroup and with an AUC equal, respectively, to 0.653 (95% CI: 0.552-0.754), 0.665 (95% CI: 0.560-0.770), 0.668 (95% CI: 0.568-0.769), and 0.670 (95% CI: 0.567-0.773) in the second, respectively. Both PHID and p2PSA/fPSAD allowed improvement in the diagnostic accuracy with respect to PHI and p2PSA/fPSA ratio, however the differences were not statistically significant (p = 0.409, 0.180 for csPCa as G ≥ Gleason grade (GG) 2 and 0.558 and 0.087 for csPCa as G ≥ GG3, respectively). We found that PHI, PHID, p2PSA/fPSA ratio, and p2PSA/fPSAD showed higher sensitivity, specificity, and positive predictive value when used to predict csPCa as GG ≥ 2, whereas negative predictive value of all four parameters was higher when used to predict GG ≥ 3. CONCLUSIONS: In men with a PSA level between 2 and 10 ng/mL, PHI and PHID, p2PSA/fPSA, and p2PSA/fPSAD showed good diagnostic performance for postoperative csPCa. However, PHID and p2PSA/fPSAD had a small advantage over PHI which needs to be further investigated for the reduction of unnecessary surgical interventions. This finding suggests that it could be a promising biomarker for making the treatment-decision strategy.

Time to progression is the main predictor of survival in patients with high-risk nonmuscle invasive bladder cancer: Results from a machine learning-based analysis of a large multi-institutional database.

BACKGROUND: In patients affected by high-risk nonmuscle invasive bladder cancer (HR-NMIBC) progression to muscle invasive status is considered as the main indicator of local treatment failure. We aimed to investigate the effect of progression and time to progression on overall survival (OS) and to investigate their validity as surrogate endpoints. METHODS: A total of 1,510 patients from 18 different institutions treated for T1 high grade NMIBC, followed by a secondary transurethral resection and BCG intravesical instillation. We relied on random survival forest (RSF) to rank covariates based on OS prediction. Cox's regression models were used to quantify the effect of covariates on mortality. RESULTS: During a median follow-up of 49.0 months, 485 (32.1%) patients progressed to MIBC, while 163 (10.8%) patients died. The median time to progression was 82 (95%CI: 78.0-93.0) months. In RSF time-to-progression and age were the most predictive covariates of OS. The survival tree defined 5 groups of risk. In multivariable Cox's regression models accounting for progression status as time-dependent covariate, shorter time to progression (as continuous covariate) was associated with longer OS (HR: 9.0, 95%CI: 3.0-6.7; P < 0.001). Virtually same results after time to progression stratification (time to progression ≥10.5 months as reference). CONCLUSION: Time to progression is the main predictor of OS in patients with high risk NMIBC treated with BCG and might be considered a coprimary endpoint. In addition, models including time to progression could be considered for patients' stratification in clinical practice and at the time of clinical trials design.

Beyond blood biomarkers: the role of SelectMDX in clinically significant prostate cancer identification.

INTRODUCTION: New potential biomarkers to pre-intervention identification of a clinically significant prostate cancer (csPCa) will prevent overdiagnosis and overtreatment and limit quality of life impairment of PCa patients. AREAS COVERED: We have developed a comprehensive review focusing our research on the increasing knowledge of the role of SelectMDX® in csPCa detection. Areas identified as clinically relevant are the ability of SelectMDX® to predict csPCa in active surveillance setting, its predictive ability when combined with multiparametric MRI and the role of SelectMDX® in the landscape of urinary biomarkers. EXPERT OPINION: Several PCa biomarkers have been developed either alone or in combination with clinical variables to improve csPCa detection. SelectMDX® score includes genomic markers, age, PSA, prostate volume, and digital rectal examination. Several studies have shown consistency in the ability to improve detection of csPCa, avoidance of unnecessary prostate biopsies, helpful in decision-making for clinical benefit of PCa patients with future well designed, and impactful studies.

BNT162b2 Elicited an Efficient Cell-Mediated Response against SARS-CoV-2 in Kidney Transplant Recipients and Common Variable Immunodeficiency Patients.

SARS-CoV-2 vaccination is the standard of care for the prevention of COVID-19 disease. Although vaccination triggers both humoral and cellular immune response, COVID-19 vaccination efficacy is currently evaluated by measuring antibodies only, whereas adaptative cellular immunity is unexplored. Our aim is to test humoral and cell-mediated response after three doses of BNT162b vaccine in two cohorts of fragile patients: Common Variable Immunodeficiency (CVID) patients and Kidney Transplant Recipients (KTR) patients compared to healthy donors. We enrolled 10 healthy controls (HCs), 19 CVID patients and 17 KTR patients. HC BNT162b third dose had successfully mounted humoral immune response. A positive correlation between Anti-Spike Trimeric IgG concentration and neutralizing antibody titer was also observed. CVID and KTR groups showed a lower humoral immune response compared to HCs. IFN-γ release induced by epitopes of the Spike protein in stimulated CD4+ and CD8+ T cells was similar among vaccinated HC, CVID and KTR. Patients vaccinated and infected showed a more efficient humoral and cell-mediated response compared to only vaccinated patients. In conclusion, CVID and KTR patients had an efficient cell-mediated but not humoral response to SARS-CoV-2 vaccine, suggesting that the evaluation of T cell responses could be a more sensitive marker of immunization in these subjects.

Thyroid Hormone Regulates the Lipid Content of Muscle Fibers, Thus Affecting Physical Exercise Performance.

Skeletal muscle (SkM) lipid composition plays an essential role in physiological muscle maintenance and exercise performance. Thyroid hormones (THs) regulate muscle formation and fuel energy utilization by modulating carbohydrates and lipid and protein metabolism. The best-known effects of THs in SkM include the promotion of mitochondrial biogenesis, the fiber-type switch from oxidative to glycolytic fibers, and enhanced angiogenesis. To assess the role of THs on the lipidic composition of SkM fibers, we performed lipidomic analyses of SkM cells and tissues, glucose tolerance experiments, and exercise performance tests. Our data demonstrated that TH treatment induces remodeling of the lipid profile and changes the proportion of fatty acids in SkM. In brief, THs significantly reduced the ratio of stearic/oleic acid in the muscle similar to what is induced by physical activity. The increased proportion of unsaturated fatty acids was linked to an improvement in insulin sensitivity and endurance exercise. These findings point to THs as critical endocrine factors affecting exercise performance and indicate that homeostatic maintenance of TH signals, by improving cell permeability and receptor stability at the cell membrane, is crucial for muscle physiology.

Predictors of Efficacy of Immune Checkpoint Inhibitors in Patients With Advanced Urothelial Carcinoma: A Systematic Review and Meta-Analysis.

INTRODUCTION: Several programmed death ligand-1 (PD1/L1) immune checkpoint inhibitors (ICIs) are approved in urothelial carcinoma (UC). PATIENTS AND METHODS: To address the need for predictors of the efficacy of ICIs in metastatic urothelial carcinoma (mUC), randomized controlled trials of PD1/L1 inhibitors alone or in combination with chemotherapy in this patient population were systematically reviewed, and differences in ICI-associated survival outcomes according to available baseline variables were quantitatively assessed. RESULTS: The quantitative analysis included 6524 patients with mUC. No visceral metastatic site (HR 0.67; 95% CI, 0.76-0.90) and high PDL-1 expression (HR 0.74; 95% CI, 0.640.87) were significantly associated with a reduced risk of death. CONCLUSION: Treatment with an ICI-containing regimen was associated with a reduced risk of death in mUC patients, which was associated with PDL-1 expression and metastatic site. Further research is warranted.

Artificial Intelligence in the Advanced Diagnosis of Bladder Cancer-Comprehensive Literature Review and Future Advancement.

Artificial intelligence is highly regarded as the most promising future technology that will have a great impact on healthcare across all specialties. Its subsets, machine learning, deep learning, and artificial neural networks, are able to automatically learn from massive amounts of data and can improve the prediction algorithms to enhance their performance. This area is still under development, but the latest evidence shows great potential in the diagnosis, prognosis, and treatment of urological diseases, including bladder cancer, which are currently using old prediction tools and historical nomograms. This review focuses on highly significant and comprehensive literature evidence of artificial intelligence in the management of bladder cancer and investigates the near introduction in clinical practice.

Impaired Seroconversion After Severe Acute Respiratory Syndrome Coronavirus 2 mRNA Vaccine in Patients With Thymic Epithelial Tumors.

INTRODUCTION: Thymic epithelial tumors (TETs) are rare malignancies associated with dysregulation of the immune system and humoral- and cell-mediated immunity abnormalities. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine is effective in preventing coronavirus disease 2019 morbidity and mortality. The aim of this study was to evaluate the seroconversion in patients with TET after two doses of mRNA vaccine. METHODS: This is a prospective study in which consecutive patients with TET were enrolled before receiving the first dose of SARS-CoV-2 mRNA vaccine (BNT162b2 by Pfizer-BioNTech). SARS-CoV-2 spike-binding immunoglobulin (Ig)G antibody serologic levels were analyzed at different time points, including before first vaccine dose (T0), 1 month after the second dose (T2), and 3 months after the second dose (T3). RESULTS: Overall, 39 patients were included in the analysis. All patients had negative antibody titer results at T0. There were 19 patients (48.7%) in the follow-up with no residual tumor lesion/s (referred as no evidence of disease), and 20 (51.3%) had evidence of disease (ED) and were receiving systemic treatment. Dysregulations of the immune system were diagnosed in 29 patients (74.4%) with Good syndrome (GS) being the most frequent immune disorder (48.7%). At univariate analysis, lack of seroconversion at T2 was significantly associated with ED (p < 0.001) and with GS (p = 0.043). A significant association with impaired seroconversion was confirmed at multivariate analysis for ED (p = 0.00101) but not for GS (p = 0.625). CONCLUSIONS: Our data revealed that patients with TET with ED had substantially higher probability of impaired seroconversion after SARS-CoV-2 mRNA vaccine as compared with patients with no evidence of disease.

The Efficacy of Flogofilm® in the Treatment of Chronic Bacterial Prostatitis as an Adjuvant to Antibiotic Therapy: A Randomized Prospective Trial.

INTRODUCTION: Bacterial prostatitis (BP) is a common prostatic infection characterized by a bimodal distribution in young and older men, with a prevalence between 5-10% among all cases of prostatitis and a high impact on quality of life. Although the management of bacterial prostatitis involves the use of appropriate spectrum antibiotics, which represent the first choice of treatment, a multimodal approach encompassing antibiotics and nutraceutical products in order to improve the efficacy of chosen antimicrobial regimen is often required. OBJECTIVE: To evaluate the efficacy of Flogofilm® in association with fluoroquinolones in patients with chronic bacterial prostatitis (CBP). METHODS: Patients diagnosed with prostatitis (positivity to Meares-Stamey Test and symptoms duration > 3 months) at the University of Naples "Federico II", Italy, from July 2021 to December 2021, were included in this study. All patients underwent bacterial cultures and trans-rectal ultrasounds. Patients were randomized into two groups (A and B) receiving antibiotic alone or an association of antibiotics plus Flogofilm® tablets containing Flogomicina® for one month, respectively. The NIH-CPSI and IPSS questionnaires were administered at baseline, four weeks, twelve and twenty-four weeks. RESULTS: A total of 96 (Group A = 47, Group B = 49) patients concluded the study protocol. The mean age was comparable, with a mean age of 34.62 ± 9.04 years for Group A and 35.29 ± 10.32 years for Group B (p = 0.755), and IPSS at the baseline was 8.28 ± 6.33 and 9.88 ± 6.89 (p = 0.256), respectively, while NIH-CPSI at baseline was 21.70 ± 4.38 and 21.67 ± 6.06 (p = 0.959), respectively. At 1, 3 and 6 months, the IPSS score was 6.45 ± 4.8 versus 4.31 ± 4.35 (p = 0.020), 5.32 ± 4.63 versus 3.20 ± 3.05 (p = 0.042) and 4.91 ± 4.47 versus 2.63 ± 3.28 (p = 0.005) for Groups A and B, respectively. Similarly, the NIH-CPSI total score at 1, 3 and 6 months was 16.15 ± 3.31 versus 13.10 ± 5.03 (p < 0.0001), 13.47 ± 3.07 versus 9.65 ± 4.23 (p < 0.0001) and 9.83 ± 2.53 versus 5.51 ± 2.84 (p < 0.0001), respectively. CONCLUSIONS: Flogofilm®, associated with fluoroquinolones, demonstrate a significant improvement in pain, urinary symptoms and quality of life in patients affected by chronic bacterial prostatitis in both IPSS and NIH-CPSI scores compared with fluoroquinolones alone.

A new biomarker panel of ultraconserved long non-coding RNAs for bladder cancer prognosis by a machine learning based methodology.

BACKGROUND: Recent studies have indicated that a special class of long non-coding RNAs (lncRNAs), namely Transcribed-Ultraconservative Regions are transcribed from specific DNA regions (T-UCRs), 100[Formula: see text] conserved in human, mouse, and rat genomes. This is noticeable, as lncRNAs are usually poorly conserved. Despite their peculiarities, T-UCRs remain very understudied in many diseases, including cancer and, yet, it is known that dysregulation of T-UCRs is associated with cancer as well as with human neurological, cardiovascular, and developmental pathologies. We have recently reported the T-UCR uc.8+ as a potential prognostic biomarker in bladder cancer. RESULTS: The aim of this work is to develop a methodology, based on machine learning techniques, for the selection of a predictive signature panel for bladder cancer onset. To this end, we analyzed the expression profiles of T-UCRs from surgically removed normal and bladder cancer tissues, by using custom expression microarray. Bladder tissue samples from 24 bladder cancer patients (12 Low Grade and 12 High Grade), with complete clinical data, and 17 control samples from normal bladder epithelium were analysed. After the selection of preferentially expressed and statistically significant T-UCRs, we adopted an ensemble of statistical and machine learning based approaches (i.e., logistic regression, Random Forest, XGBoost and LASSO) for ranking the most important diagnostic molecules. We identified a signature panel of 13 selected T-UCRs with altered expression profiles in cancer, able to efficiently discriminate between normal and bladder cancer patient samples. Also, using this signature panel, we classified bladder cancer patients in four groups, each characterized by a different survival extent. As expected, the group including only Low Grade bladder cancer patients had greater overall survival than patients with the majority of High Grade bladder cancer. However, a specific signature of deregulated T-UCRs identifies sub-types of bladder cancer patients with different prognosis regardless of the bladder cancer Grade. CONCLUSIONS: Here we present the results for the classification of bladder cancer (Low and High Grade) patient samples and normal bladder epithelium controls by using a machine learning application. The T-UCR's panel can be used for learning an eXplainable Artificial Intelligent model and develop a robust decision support system for bladder cancer early diagnosis providing urinary T-UCRs data of new patients. The use of this system instead of the current methodology will result in a non-invasive approach, reducing uncomfortable procedures (such as cystoscopy) for the patients. Overall, these results raise the possibility of new automatic systems, which could help the RNA-based prognosis and/or the cancer therapy in bladder cancer patients, and demonstrate the successful application of Artificial Intelligence to the definition of an independent prognostic biomarker panel.

Emerging RNA-Based Therapeutic and Diagnostic Options: Recent Advances and Future Challenges in Genitourinary Cancers.

Renal cell carcinoma, bladder cancer, and prostate cancer are the most widespread genitourinary tumors. Their treatment and diagnosis have significantly evolved over recent years, due to an increasing understanding of oncogenic factors and the molecular mechanisms involved. Using sophisticated genome sequencing technologies, the non-coding RNAs, such as microRNAs, long non-coding RNAs, and circular RNAs, have all been implicated in the occurrence and progression of genitourinary cancers. Interestingly, DNA, protein, and RNA interactions with lncRNAs and other biological macromolecules drive some of these cancer phenotypes. Studies on the molecular mechanisms of lncRNAs have identified new functional markers that could be potentially useful as biomarkers for effective diagnosis and/or as targets for therapeutic intervention. This review focuses on the mechanisms underlying abnormal lncRNA expression in genitourinary tumors and discusses their role in diagnostics, prognosis, and treatment.

Radiogenomics in Renal Cancer Management-Current Evidence and Future Prospects.

Renal cancer management is challenging from diagnosis to treatment and follow-up. In cases of small renal masses and cystic lesions the differential diagnosis of benign or malignant tissues has potential pitfalls when imaging or even renal biopsy is applied. The recent artificial intelligence, imaging techniques, and genomics advancements have the ability to help clinicians set the stratification risk, treatment selection, follow-up strategy, and prognosis of the disease. The combination of radiomics features and genomics data has achieved good results but is currently limited by the retrospective design and the small number of patients included in clinical trials. The road ahead for radiogenomics is open to new, well-designed prospective studies, with large cohorts of patients required to validate previously obtained results and enter clinical practice.

A Neural Network Model Combining [-2]proPSA, freePSA, Total PSA, Cathepsin D, and Thrombospondin-1 Showed Increased Accuracy in the Identification of Clinically Significant Prostate Cancer.

BACKGROUND: The Prostate Health Index (PHI) and Proclarix (PCLX) have been proposed as blood-based tests for prostate cancer (PCa). In this study, we evaluated the feasibility of an artificial neural network (ANN)-based approach to develop a combinatorial model including PHI and PCLX biomarkers to recognize clinically significant PCa (csPCa) at initial diagnosis. METHODS: To this aim, we prospectively enrolled 344 men from two different centres. All patients underwent radical prostatectomy (RP). All men had a prostate-specific antigen (PSA) between 2 and 10 ng/mL. We used an artificial neural network to develop models that can identify csPCa efficiently. As inputs, the model uses [-2]proPSA, freePSA, total PSA, cathepsin D, thrombospondin, and age. RESULTS: The output of the model is an estimate of the presence of a low or high Gleason score PCa defined at RP. After training on a dataset of up to 220 samples and optimization of the variables, the model achieved values as high as 78% for sensitivity and 62% for specificity for all-cancer detection compared with those of PHI and PCLX alone. For csPCa detection, the model showed 66% (95% CI 66-68%) for sensitivity and 68% (95% CI 66-68%) for specificity. These values were significantly different compared with those of PHI (p < 0.0001 and 0.0001, respectively) and PCLX (p = 0.0003 and 0.0006, respectively) alone. CONCLUSIONS: Our preliminary study suggests that combining PHI and PCLX biomarkers may help to estimate, with higher accuracy, the presence of csPCa at initial diagnosis, allowing a personalized treatment approach. Further studies training the model on larger datasets are strongly encouraged to support the efficiency of this approach.

Repositioning of Cefuroxime as novel selective inhibitor of the thyroid hormone activating enzyme type 2 deiodinase.

The iodothyronine deiodinases constitute a family of three selenoenzymes regulating the intracellular metabolism of Thyroid Hormones (THs, T4 and T3) and impacting on several physiological processes, including energy metabolism, development and cell differentiation. The type 1, 2 and 3 deiodinases (D1, D2, and D3), are sensitive, rate-limiting components within the TH axis, and rapidly control TH action in physiological conditions or disease. Notably, several human pathologies are characterized by deiodinases deregulation (e.g., inflammation, osteoporosis, metabolic syndrome, muscle wasting and cancer). Consequently, these enzymes are golden targets for the identification and development of pharmacological compounds endowed with modulatory activities. However, until now, the portfolio of inhibitors for deiodinases is limited and the few active compounds lack selectivity. Here, we describe the cephalosporin Cefuroxime as a novel D2 specific inhibitor. In both in vivo and in vitro settings, Cefuroxime acts as a selective inhibitor of D2 activity, without altering the enzymatic activity of D1 and D3. By inhibiting TH activation in target tissues, Cefuroxime alters the sensitivity of the hypothalamus-pituitary axis and interferes with the central regulation of THs levels, and is thus eligible as a potential new regulator of hyperthyroid pathologies, which affect thousands of patients worldwide.

Low Interferon-γ Levels in Cord and Peripheral Blood of Pregnant Women Infected with SARS-CoV-2.

COVID-19 is characterized by the immune system's overreaction resulting in a 'cytokine storm', consisting in a massive release of cytokine into the bloodstream, leading to local and systemic inflammatory response. This clinical picture is further complicated in case of infection of patients with a peculiar immunological status, such as pregnancy. In this paper, we focused on Interferon-γ, which plays a pivotal immunomodulatory role in normal pregnancy and fetal development, as well as in defense against pathogens. In this study, we compared the levels of Interferon-γ and the Interferon autoantibodies of the peripheral and cord blood of pregnant women with confirmed mild COVID-19 and healthy pregnant women. The Interferon-γ was significantly lower both in the peripheral and cord blood of SARS-CoV-2-positive mothers, suggesting that infection can affect the fetal microenvironment even without severe maternal symptoms. In conclusion, further studies are needed to clarify whether lower levels of Interferon-γ due to SARS-CoV-2 infection affect the development or infection susceptibility of infants born to SARS-CoV-2-infected mothers.

Vandetanib downregulates type 2 deiodinase in fibro/adipogenic progenitors.

Treatment with tyrosine kinase inhibitors (TKIs) has been associated with alterations in circulating thyroid hormone levels, possibly related to perturbations in peripheral thyroid hormone metabolism. In this study, we evaluated the effect of the multi-kinase inhibitor vandetanib on the expression of the three deiodinase selenoenzymes, responsible for the thyroid hormone activation (type 1 and type 2 deiodinases) or for its inactivation (type 3 deiodinase). Here, we show that the multi-kinase inhibitor vandetanib determines a strong cell-specific downregulation of type 2 deiodinase (D2) expression and a significant reduction in D2 enzymatic activity. This occurs in the diffused population of fibro/adipogenic progenitors, which reside in different tissues - including the muscles - and normally express D2. Given the widespread diffusion of mesenchymal cells within the body, our results may explain at least partially the alterations in thyroid hormone levels that occur in vandetanib-treated patients. Our findings represent a step forward into the understanding of the mechanisms by which TKIs induce hypothyroidism and identify a resident cell population in which such an effect takes place.