Perivascular and endomysial macrophages expressing VEGF and CXCL12 promote angiogenesis in anti-HMGCR immune-mediated necrotizing myopathy.

OBJECTIVES: To study the phenotype of macrophage infiltrates and their role in angiogenesis in different idiopathic inflammatory myopathies (IIMs). METHODS: The density and distribution of the subpopulations of macrophages subsets (M1, inducible nitric oxide+, CD11c+; M2, arginase-1+), endomysial capillaries (CD31+, FLK1+), degenerating (C5b-9+) and regenerating (NCAM+) myofibres were investigated by immunohistochemistry in human muscle samples of diagnostic biopsies from a large cohort of untreated patients (n: 81) suffering from anti-3-hydroxy-3-methylglutaryl coenzyme A reductase (anti-HMGCR)+ immune mediated necrotizing myopathy (IMNM), anti-signal recognition particle (anti-SRP)+ IMNM, seronegative IMNM, DM, PM, PM with mitochondrial pathology, sporadic IBM, scleromyositis, and anti-synthetase syndrome. The samples were compared with mitochondrial myopathy and control muscle samples. RESULTS: Compared with the other IIMs and controls, endomysial capillary density (CD) was higher in anti-HMGCR+ IMNM, where M1 and M2 macrophages, detected by confocal microscopy, infiltrated perivascular endomysium and expressed angiogenic molecules such as VEGF-A and CXCL12. These angiogenic macrophages were preferentially associated with CD31+ FLK1+ microvessels in anti-HMGCR+ IMNM. The VEGF-A+ M2 macrophage density was significantly correlated with CD (rS: 0.98; P: 0.0004). Western blot analyses revealed increased expression levels of VEGF-A, FLK1, HIF-1α and CXCL12 in anti-HMGCR+ IMNM. CD and expression levels of these angiogenic molecules were not increased in anti-SRP+ and seronegative IMNM, offering additional, useful information for differential diagnosis among these IIM subtypes. CONCLUSION: Our findings suggest that in IIMs, infiltrating macrophages and microvascular cells interactions play a pivotal role in coordinating myogenesis and angiogenesis. This reciprocal crosstalk seems to distinguish anti-HMGCR associated IMNM.

Thyroid Cancers: From Surgery to Current and Future Systemic Therapies through Their Molecular Identities.

Differentiated thyroid cancers (DTC) are commonly and successfully treated with total thyroidectomy plus/minus radioiodine therapy (RAI). Medullary thyroid cancer (MTC) is only treated with surgery but only intrathyroidal tumors are cured. The worst prognosis is for anaplastic (ATC) and poorly differentiated thyroid cancer (PDTC). Whenever a local or metastatic advanced disease is present, other treatments are required, varying from local to systemic therapies. In the last decade, the efficacy of the targeted therapies and, in particular, tyrosine kinase inhibitors (TKIs) has been demonstrated. They can prolong the disease progression-free survival and represent the most important therapeutic option for the treatment of advanced and progressive thyroid cancer. Currently, lenvatinib and sorafenib are the approved drugs for the treatment of RAI-refractory DTC and PDTC while advanced MTC can be treated with either cabozantinib or vandetanib. Dabrafenib plus trametinib is the only approved treatment by FDA for BRAFV600E mutated ATC. A new generation of TKIs, specifically for single altered oncogenes, is under evaluation in phase 2 and 3 clinical trials. The aim of this review was to provide an overview of the current and future treatments of thyroid cancer with regards to the advanced and progressive cases that require systemic therapies that are becoming more and more targeted on the molecular identity of the tumor.

TGFß1-Smad canonical and -Erk noncanonical pathways participate in interleukin-17-induced epithelial-mesenchymal transition in Sjögren's syndrome.

Interleukin-17 (IL-17) is a pleiotropic cytokine that plays a primary role in triggering epithelial-mesenchymal transition (EMT) in many chronic inflammatory diseases. EMT plays a critical role in the progression of salivary gland (SG) fibrosis in primary Sjögren's syndrome (pSS). This study focused on the activation of the canonical TGF-ß1/Smad2/3 and noncanonical TGF-ß1/Erk1/2 pathways in IL-17-dependent TGFß1-induced EMT in human SG epithelial cells (SGEC) derived from healthy subjects. The expression of phosphorylated Smad2/3 and Erk1/2 during IL-17 treatment-stimulated EMT was evaluated in healthy SGEC. Cotreatment with IL-17 and specific TGFß receptor type I kinase inhibitor SB431542, or Erk 1/2 inhibitor U0126, abrogates the corresponding morphological changes and EMT phenotypic markers expression in healthy SGEC. Interestingly, inhibition of canonical TGFß1/Smad2/3 signal transduction had no effect on activation of the noncanonical TGFß1/Erk1/2/EMT pathway, suggesting that the two pathways act independently in activating IL-17-dependent EMT in SGEC.

The TGF-ß1 Signaling Pathway as an Attractive Target in the Fibrosis Pathogenesis of Sjögren's Syndrome.

Transforming growth factor ß1 (TGF-ß1) plays a crucial role in the induction of fibrosis, often associated with chronic phases of inflammatory diseases contributing to marked fibrotic changes that compromise normal organ function. The TGF-ß1 signal exerts its biological effects via the TGF-ß/SMAD/Snail signaling pathway, playing an important pathogenic role in several fibrotic diseases. It has as yet been poorly investigated in the chronic autoimmune disease Sjögren's syndrome (SS). Here, we firstly tested, by immunohistochemistry, whether the TGF-ß1/SMAD/Snail signaling pathway is triggered in human pSS salivary glands (SGs). Next, healthy salivary gland epithelial cell (SGEC) cultures derived from healthy donors were exposed to TGF-ß1 treatment, and the relative gene and protein levels of SMAD2/3/4, Snail, E-cadherin, vimentin, and collagen type I were compared by semiquantitative RT-PCR, quantitative real-time PCR, and Western blot analysis. We observed, both at gene and protein levels, higher expression of SMAD2, 3, and 4 and Snail in the SGEC exposed by TGF-ß1 compared to untreated healthy SGEC. Additionally, in TGF-ß1-treated samples, we found a significant reduction in the epithelial phenotype marker E-cadherin and an increase in the mesenchymal phenotype markers vimentin and collagen type I compared to those in untreated SGEC, indicating that TGF-ß1 induces the EMT via the TGF-ß1/SMAD/Snail signaling pathway. Therefore, by using the specific TGF-ß receptor 1 inhibitor SB-431542 in healthy SGEC treated with TGF-ß1, we showed a significant reduction of the fibrosis markers vimentin and collagen type I while the epithelial marker E-cadherin returns to levels similar to untreated healthy SGEC. These data demonstrate that TGF-ß1 is an important key factor in the transition phase from SG chronic inflammation to fibrotic disease. Characteristic changes in the morphology and function of TGF-ß1-treated healthy SGEC further confirm that TGF-ß1 plays a significant role in EMT-dependent fibrosis.

Lenvatinib: a new option for the treatment of advanced iodine refractory differentiated thyroid cancer?

Lenvatinib mesylate (E7080; 4-[3-chloro-4-(N'-cyclopropylureido) phenoxy] 7-methoxyquinoline-6-carboxamide mesylate) is an oral molecule that inhibits multiple tyrosine kinase receptors such as VEGF-R-1-3, FGF-R-1-4, RET, c-KIT and PDGF-R-ß. Phase I studies identified the maximum tolerated dose to be 25 mg daily that, in fasting treated patients, is rapidly absorbed with maximum concentrations achieved within 3 h of administration. In these studies, lenvatinib showed activity in solid tumors. Subsequently, Phase II studies in thyroid cancer, in particular differentiated thyroid cancer (DTC), confirmed good clinically significant activity and the recently published Phase III SELECT trial reported median progression-free survival was 18.3 months with lenvatinib versus 3.6 months with placebo (hazard ratio for progression or death: 0.21; 99% CI: 0.14-0.31; p < 0.001). Treatment-related adverse effects occurred in more than 40% of patients on lenvatinib. These were hypertension (in 67.8% of the patients), diarrhea (in 59.4%), fatigue or asthenia (in 59.0%), decreased appetite (in 50.2%), decreased weight (in 46.4%) and nausea (in 41.0%). Discontinuations of lenvatinib because of adverse effects occurred in 37 patients (14.2%) compared with three patients who received placebo (2.3%). Six of 20 deaths in patients on lenvatinib were considered to be drug-related. Lenvatinib has been licensed by the US FDA and EMA based on these data and provides an option for the treatment of radioiodine refractory DTC.

Mast cell density in Merkel cell carcinoma and its correlation with prognostic features and MCPyV status: a pilot study.

Merkel cell carcinoma (MCC) is a rare, highly aggressive, primitive neuroendocrine carcinoma of the skin, the origin of which is not yet fully understood. Numerous independent prognostic factors have been investigated in an attempt to understand which are the most important parameters to indicate in the histological diagnostic report of MCC. Of these, mast cells have only been studied in one paper before this one. We present a retrospective descriptive study of 13 cases of MCC, received at the Department of Pathology over a 20-year period (2003-2023 inclusive) on which we performed a study using whole-slide (WSI) morphometric analysis scanning platform Aperio Scanscope CS for the detection and spatial distribution of mast cells, using monoclonal anti-tryptase antibody and anti-CD34 monoclonal antibody to study the density of microvessels. In addition, we analyzed MCPyV status with the antibody for MCPyV large T-antigen (Clone CM2B4). We found statistically significant correlation between mast cell density and local recurrence/distant metastasis/death-of-disease (p = 0.008). To our knowledge, we firstly reported that MCPyV ( -) MCC shows higher mast cells density compared to MCPyV ( +) MCC, the latter well known to be less aggressive. Besides, the median vascular density did not show no significant correlation with recurrence/metastasis/death-of-disease, (p = 0.18). Despite the small sample size, this paper prompts future studies investigating the role of mast cell density in MCC.

HAND-FOOT SYNDROME IN SORAFENIB AND LENVATINIB TREATMENT FOR ADVANCED THYROID CANCER.

OBJECTIVE: The aim of this study was to assess the clinical impact of hand-foot syndrome (HFS) during treatment with two multikinase inhibitors, sorafenib and lenvatinib, in a large group of patients with advanced thyroid cancer. Moreover, we looked for possible associations between HFS occurrence and clinical and pathological features. METHODS: We retrospectively evaluated 239 patients with advanced thyroid cancer: 165 treated with lenvatinib and 74 with sorafenib. Statistical analysis was performed to verify which features could be correlated with HFS development. RESULTS: HFS was observed in 35/74 (47.4%) and in 43/165 (26.7%) patients treated with sorafenib or lenvatinib, respectively. The median latency from the drug beginning and HFS appearance was 27 days for sorafenib and 2.9 months for lenvatinib. G3/G4 toxicity was observed in 16/35 (45.7%) patients treated with sorafenib and only in 3/43 (7%) treated with lenvatinib. Drug dose reduction due to HFS was required in 19/74 (25.7%) and 3/165 (1.8%) patients treated with sorafenib and lenvatinib, respectively. HFS occurrence was significantly associated with a longer duration of therapy in both groups. CONCLUSIONS: HFS was a frequent adverse event during both lenvatinib and sorafenib therapy, with a higher frequency and toxicity grade during sorafenib treatment. HFS was the most frequent reason for drug reduction or discontinuation in patient treated with sorafenib. Early diagnosis of HFS is important to allow early intervention, possibly in a multidisciplinary setting, and to avoid treatment discontinuation, which is highly relevant to obtain the maximum effectiveness of systemic therapy.

Double Immunohistochemical Staining on Formalin-Fixed Paraffin-Embedded Tissue Samples to Study Vascular Co-option.

Vascular co-option is a non-angiogenic mechanism whereby tumor growth and progression move on by hijacking the pre-existing and nonmalignant blood vessels and is employed by various tumors to grow and metastasize.The histopathological identification of co-opted blood vessels is complex, and no specific markers were defined, but it is critical to develop new and possibly more effective therapeutic strategies. Here, in glioblastoma, we show that the co-opted blood vessels can be identified, by double immunohistochemical staining, as weak CD31+ vessels with reduced P-gp expression and proliferation and surrounded by highly proliferating and P-gp- or S100A10-expressing tumor cells. Results can be quantified by the Aperio Colocalization algorithm, which is a valid and robust method to handle and investigate large data sets.

Significance of Thyroglobulin Autoantibodies in Patients With Thyroid Cancer Treated With Lenvatinib.

Context: Serum thyroglobulin (Tg) is a highly sensitive and specific tumor marker, employed in post-operative management of patients with differentiated thyroid carcinomas. Tumor shrinkage of radioiodine-refractory thyroid cancer (RAIR-DTC) treated with multitarget kinase inhibitors as lenvatinib, expressed according to the Response Evaluation Criteria in Solid Tumors (RECIST), is also associated with a drastic reduction of Tg levels. However, interference caused by circulating thyroglobulin autoantibodies (TgAb) represents the main limitation in the clinical use of Tg. Objective: To evaluate if in RAIR-DTC TgAb could be considered a surrogate marker of Tg in monitoring response to treatment with lenvatinib. Design: We retrospectively evaluated patients who had started lenvatinib and correlated serum Tg and TgAb with the radiological response across visits. Setting: University of Pisa, Italy. Patients: We selected 9/97 RAIR-DTC patients with detectable TgAb. Intervention: None. Main Outcome Measures: None. Results: Tg values correlated neither with TgAb title nor with radiological response across visits. Greater decreases in TgAb titer correlated with favorable radiological response to lenvatinib after 1 month (Spearman's correlation = 0.74, P = .021) and 6 months (correlation = 0.61, P = .079). According to RECIST, patients with partial response showed a ∼10-fold greater decrease in TgAb compared to those with stable disease at 1 month (median TgAb decrease: -142 vs -14 IU/mL, P = .01) and those with progressive disease at 6 months (median TgAb decrease: -264 vs-24 IU/mL, P = .04). Conclusion: TgAb evaluation may represent a reliable surrogate marker for Tg trend in evaluating response of RAIR-DTC to treatment with lenvatinib. A multicentric study would be useful to confirm our results.

PTX3 shapes profibrotic immune cells and epithelial/fibroblast repair and regeneration in a murine model of pulmonary fibrosis.

The long pentraxin 3 (PTX3) is protective in different pathologies but was not analyzed in-depth in Idiopathic Pulmonary Fibrosis (IPF). Here, we have explored the influence of PTX3 in the bleomycin (BLM)-induced murine model of IPF by looking at immune cells (macrophages, mast cells, T cells) and stemness/regenerative markers of lung epithelium (SOX2) and fibro-blasts/myofibroblasts (CD44) at different time points that retrace the progression of the disease from onset at day 14, to full-blown disease at day 21, to incomplete regression at day 28. We took advantage of transgenic PTX3 overexpressing mice (Tie2-PTX3) and Ptx3 null ones (PTX3-KO) in which pulmonary fibrosis was induced. Our data have shown that PTX3 overexpression in Tie2-PTX3 compared to WT or PTX3-KO: reduced CD68+ and CD163+ macrophages and the Tryptase+ mast cells during the whole experimental time; on the contrary, CD4+ T cells are consistently present on day 14 and dramatically decreased on day 21; CD8+ T cells do not show significant differences on day 14, but are significantly reduced on day 21; SOX2 is reduced on days 14 and 21; CD44 is reduced on day 21. Therefore, PTX3 could act on the proimmune and fibrogenic microenvironment to prevent fibrosis in BLM-treated mice.

Active surveillance in differentiated thyroid cancer: a strategy applicable to all treatment categories response.

Currently, the differentiated thyroid cancer (DTC) management is shifted toward a tailored approach based on the estimated risks of recurrence and disease-specific mortality. While the current recommendations on the management of metastatic and progressive DTC are clear and unambiguous, the management of slowly progressive or indeterminate disease varies according to different centers and different physicians. In this context, active surveillance (AS) becomes the main tool for clinicians, allowing them to plan a personalized therapeutic strategy, based on the risk of an unfavorable prognosis, and to avoid unnecessary treatment. This review analyzes the main possible scenarios in treated DTC patients who could take advantage of AS.

The Tumor Microenvironment in Classic Hodgkin's Lymphoma in Responder and No-Responder Patients to First Line ABVD Therapy.

Although classical Hodgkin lymphoma (CHL) is typically curable, 15-25% of individuals eventually experience a relapse and pass away from their disease. In CHL, the cellular microenvironment is constituted by few percent of H/RS (Hodgkin/Reed-Sternberg) tumor cells surrounded from a heterogeneous infiltration of inflammatory cells. The interplay of H/RS cells with other immune cells in the microenvironment may provide novel strategies for targeted immunotherapies. In this paper we analyzed the microenvironment content in CHL patients with responsive disease (RESP) and patients with relapsed/refractory disease to treatment (REL). Our results indicate the increase of CD68+ and CD163+ macrophages, the increase of PDL-1+ cells and of CD34+ microvessels in REL patients respective to RESP patients. In contrast we also found the decrease of CD3+ and of CD8+ lymphocytes in REL patients respective to RESP patients. Finally, in REL patients our results show the positive correlation between CD68+ macrophages and PDL-1+ cells as well as a negative correlation between CD163+ and CD3+.

Thyroid autoimmunity, thyroglobulin autoantibodies, and thyroid cancer prognosis.

The relevance of thyroid autoimmunity to the prognosis of papillary thyroid carcinoma is still unsettled. We decided to investigate the impact of thyroid autoimmunity on the prognosis of papillary thyroid carcinoma and the handling of TgAbs. We evaluated the clinical course of a large group of patients according to the presence (PTC-LT) or absence (PTC) of lymphocytic thyroiditis at histology. We studied 194 consecutive patients with a diagnosis of PTC and treated them with total thyroidectomy plus ¹³¹I ablation between 2007 and 2009. Median follow-up (with 25th-75th percentiles) was 84.0 (56.4-118.0) months. The remission criteria were: basal Tg < 0.2 ng/mL (or stimulated Tg: < 1), TgAbs < 8 IU/mL (otherwise 'decreasing TgAb trend', a decline of ≥20% in sequential TgAb measurements) and unremarkable imaging. PTC-LT and PTC patients had comparable treatment.TgAbs were detectable in 72.5% of PTC-LT and 16.5% of PTC patients. Time to remission was longer in the detectable than in the undetectable TgAb cohort (28.5 vs· 7.5 months (median); HR: 0.54, CI: 0.35-0.83, P = 0.005). When comparing PTC-LT to PTC patients, the difference was maintained in the detectable TgAb (29.3 vs 13.0 months; HR: 0.38, CI: 0.18-0.80; P = 0.01) but not in the undetectable TgAb cohort (7.7 vs 7.3 months; HR: 0.90, CI: 0.55-1.47; P = 0.68). Using the decreasing TgAb trend, the influence of detectable TgAbs on time to remission was abolished. Thyroid autoimmunity does not influence the prognosis of papillary thyroid carcinoma. A decreasing TgAb trend seems an appropriate criterion to establish the remission of papillary thyroid carcinoma.

Tumor Microenvironment and Microvascular Density in Human Glioblastoma.

Glioblastoma (GBM) is a very aggressive form of cancer affecting the central nervous system. Although it occurs almost exclusively in the brain, glioblastoma can also appear in the brainstem, cerebellum, and spinal cord. It is characterized by high rates of proliferation, invasion, and necrosis. Moreover, GBM is a highly vascularized tumor and presents resistance to therapy. Recent data indicate that GBM cells are surrounded by a microenvironment (TME) which includes a complex network constituted of cellular/extracellular components and vessels able to influence both tumor growth and angiogenesis. In this retrospective study, we evaluated 30 bioptic specimens of adult patients diagnosed with IDH1 wild type GBM taken at the time of the first diagnosis. Each section has been divided into two experimental zones: the tumor side and the healthy surrounding tissue. We performed a series of immunohistochemical stainings with the purpose of evaluating the presence of total and M2 macrophages, CD4+-, CD8+-lymphocytes, and CD34+ microvessels. In addition, we have also evaluated the percentage of cells expressing bcl6 and p53 to determine any possible correlations with TME. Our data showed a significant increase in the total and M2 type macrophages, of CD4+ and CD8+ lymphocytes, and of CD34+ microvessels in the tumoral area respective to the healthy zone. We also confirmed our previous data showing the higher number of p53 and BCL6+ cells in the tumor area with a positive correlation between BCL6 and CD34+ microvessels. In conclusion, the data that came from this work support the important role played by microenvironment components in GBM progression. These results could contribute to the generation of new specific therapies useful in preventing GBM progression.

Differential P-Glycoprotein/CD31 Expression as Markers of Vascular Co-Option in Primary Central Nervous System Tumors.

BACKGROUND: Vascular co-option is one of the main features of brain tumor progression. It is identified using histopathological analysis, but no antibody-specific markers were found, and no universally accepted histological features were defined. METHODS: We employed double immunohistochemical stainings for CD31, P-gp, S100A10, and mitochondria on formalin-fixed, paraffin-embedded human samples of IDH-WT glioblastoma, IDH-mutant astrocytoma, and meningioma to study vascular co-option across different brain tumors and across normal, peritumoral, and intratumoral areas using the Aperio colocalization algorithm, which is a valid and robust method to handle and investigate large data sets. RESULTS: The results have shown that (i) co-opted vessels could be recognized by the presence of metabolically overactive (evaluated as mitochondria expression) and P-gp+ or S100A10+ tumor cells surrounding CD31+ endothelial cells; (ii) vascular co-option occurs in the intratumoral area of meningioma and astrocytoma; and (iii) vascular co-option is prevalent in peritumoral glioblastoma area. CONCLUSIONS: The described approach identifies new markers for cellular components of the vessel wall and techniques that uncover the order and localization of vascularization mechanisms, which may contribute to developing new and possibly more effective therapeutic strategies.

VAMP-2, SNAP-25A/B and syntaxin-1 in glutamatergic and GABAergic synapses of the rat cerebellar cortex.

BACKGROUND: The aim of this study was to assess the distribution of key SNARE proteins in glutamatergic and GABAergic synapses of the adult rat cerebellar cortex using light microscopy immunohistochemical techniques. Analysis was made of co-localizations of vGluT-1 and vGluT-2, vesicular transporters of glutamate and markers of glutamatergic synapses, or GAD, the GABA synthetic enzyme and marker of GABAergic synapses, with VAMP-2, SNAP-25A/B and syntaxin-1. RESULTS: The examined SNARE proteins were found to be diffusely expressed in glutamatergic synapses, whereas they were rarely observed in GABAergic synapses. However, among glutamatergic synapses, subpopulations which did not contain VAMP-2, SNAP-25A/B and syntaxin-1 were detected. They included virtually all the synapses established by terminals of climbing fibres (immunoreactive for vGluT-2) and some synapses established by terminals of parallel and mossy fibres (immunoreactive for vGluT-1, and for vGluT-1 and 2, respectively). The only GABA synapses expressing the SNARE proteins studied were the synapses established by axon terminals of basket neurons. CONCLUSION: The present study supplies a detailed morphological description of VAMP-2, SNAP-25A/B and syntaxin-1 in the different types of glutamatergic and GABAergic synapses of the rat cerebellar cortex. The examined SNARE proteins characterize most of glutamatergic synapses and only one type of GABAergic synapses. In the subpopulations of glutamatergic and GABAergic synapses lacking the SNARE protein isoforms examined, alternative mechanisms for regulating trafficking of synaptic vesicles may be hypothesized, possibly mediated by different isoforms or homologous proteins.

Ca19.9 Positivity and Doubling Time Are Prognostic Factors of Mortality in Patients with Advanced Medullary Thyroid Cancer with No Evidence of Structural Disease Progression According to Response Evaluation Criteria in Solid Tumors.

Background: Serum Ca19.9 positivity is a prognostic factor for mortality in patients with advanced medullary thyroid cancer (aMTC), independently from calcitonin doubling time (DT). However, it is unknown whether aMTC patients who become positive for Ca19.9 also have progressive disease (PD) according to response evaluation criteria in solid tumors (RECIST) and whether Ca19.9 DT has a role in the management of aMTC patients. The aims of this study were to evaluate whether in aMTC, when serum Ca19.9 becomes positive, PD develops, and to determine the role of Ca19.9 DT in predicting mortality and PD. Patients and Methods: Serum Ca19.9 was periodically measured in 107 aMTC patients, and the DTs were calculated. Restaging of the disease was radiologically performed in 104 of 107 patients and PD was evaluated according to RECIST. Results: At the end of follow-up, 25 of 107 patients were Ca19.9 positive and PD was identified in 30 of 104 patients. No significant association was found between Ca19.9 positivity and PD, while there was a significant association between Ca19.9 positivity and mortality (p < 0.0001). Ca19.9 DTs <6 months and <1 year were not associated with PD but were associated with mortality (p < 0.0001 and p < 0.0001, respectively). In particular, 3 patients who had a Ca19.9 DT <6 months with no evidence of PD according to RECIST died of their disease after 6, 5, and 3 months, respectively. Conclusions: Serum Ca19.9 positivity and DTs <6 months and <1 year are prognostic factors for mortality but not for PD. Serum Ca19.9 positivity and DTs <6 months and <1 year should be considered in the decision-making process of whether to initiate systemic therapy even if there is no evidence of PD according to RECIST.

RET mutated C-cells proliferate more rapidly than non-mutated neoplastic cells.

A statistically significant higher prevalence of the RET p.Met918Thr somatic mutation, identified by direct sequencing, was previously reported in MTC > 2 cm than in smaller tumors. Aim of this study was to correlate the full RET and RAS mutation profile, identified by a Next Generation Sequencing approach, with the growth rate, proliferation and tumor size of MTC. Data of 149 sporadic MTC patients were correlated with RET mutations and Ki67 positivity. Eighty-one cases had a somatic RET mutation, 40 had a RAS mutation and 28 were negative. A statistically significant higher prevalence of RET mutations was found in MTC > 2 cm. A higher prevalence of RET more aggressive mutations, higher allelic frequencies and, higher percentage of Ki67 positive cells were found in larger tumors which had also a worse outcome. Our study highlights the predominant role of RET somatic mutations in MTC tumorigenesis. We demonstrate that RET mutation prevalence and allelic frequency (AF) are significantly higher in larger tumors. Based on these results, we can conclude that RET mutated C-cells's growth and proliferation are more rapid than those of non-mutated cells and give origin to bigger and more aggressive MTC.

Prevalence and Risk Factors of Developing Fistula or Organ Perforation in Patients Treated with Lenvatinib for Radioiodine-Refractory Thyroid Cancer.

INTRODUCTION: Tyrosine kinase inhibitors represent a better treatment in patients with radioiodine-refractory differentiated thyroid cancer (RAI-R DTC). Lenvatinib is usually well-tolerated, but sometimes, it is associated with serious and even life-threatening side effects. The aim of this study was to evaluate the prevalence of and the potential risk factors for fistula and/or organ perforation in RAI-R DTC patients treated with lenvatinib. METHODS: This study included data from advanced and progressive RAI-R DTC patients treated with lenvatinib from February 2011 to February 2020 who were followed up at a single center. The clinical-pathological features and the biochemical and morphological results of the patients were collected at the time of starting lenvatinib and during the follow-up. RESULTS: Fourteen of 95 (14.7%) locally advanced or metastatic RAI-R DTC patients treated with lenvatinib developed a fistula or organ perforation. Nine of 14 (64.3%) patients had tumor infiltration of the trachea, bronchus, esophagus, pleura, or bladder. Five of 14 (35.7%) had a bowel perforation, but only 2 had preexisting diverticulosis. Evaluation of the risk factors for developing a fistula or organ perforation showed that the presence of tumor infiltration and the tumor histology (papillary and poorly differentiated vs. follicular and Hurthle thyroid cancer) were significantly correlated with the development of a fistula or organ perforation (p = 0.003 and p = 0.02, respectively). In the subgroup of patients with tumor infiltration, we found that the papillary thyroid cancer histotype was the only potential predictor of fistula development. External beam radiation therapy (EBRT), the starting dose of lenvatinib, and the duration of treatment were not relevant for the development of fistula. CONCLUSIONS: In metastatic thyroid cancer patients treated with lenvatinib, the presence of tumor infiltration and histological type should be considered as potential risk factors for the development of fistula or organ perforation, although they do not represent an absolute contraindication. Although EBRT and the presence of diverticulosis were not significantly associated with the development of fistula and organ perforation, they should be regarded as potential additional reasons for the development of these complications. According to our findings, there is no reason to start lenvatinib at a lower daily dose when tumor infiltration is present.

Thyroid cancer and COVID-19: experience at one single thyroid disease referral center.

PURPOSE: Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) is challenging health systems all over the world. Cancer patients have a higher risk of being infected by SARS-Cov-2 and higher coronavirus disease 2019 (COVID-19) severity and mortality. Up to date, there were no data about COVID-19 in patients with thyroid cancer (TCs). The aim of the study was to describe the prevalence of COVID-19 in a well-characterized series of TC patients evaluated for the persistence of the neoplastic disease from March to September 2020; as secondary objective, we looked for the COVID-19 disease severity in a subgroup of multimetastatic TC patients. METHODS: We evaluated 1464 patients affected by persistent TC: 67 patients who were taking multikinase inhibitors (MKIs) and 1397 under active surveillance for a persistent but stable disease. During the clinical evaluation, all patients were specifically investigated about a positive history of Sars-Cov-2 infection. RESULTS: SARS-Cov-2 infection was identified in 4/1464 (0.3%) cases of patients affected by TC. We identified three cases among patients under active surveillance (0.2%), and one case among patients treated with MKI systemic therapy (1/67, 1.5%). This patient was taking vandetanib for metastatic medullary thyroid cancer (MTC), when he came to our attention referring severe fatigue, dyspnea for light physical activities. He presented a mild COVID-19 and he received exclusively supportive care. After a multidisciplinary consultation, we decided against the discontinuation of vandetanib. After 2 months from the infection, he did not present any signs of active infection, and the MTC metastatic disease was stable. CONCLUSIONS: We showed that COVID-19 is not more frequent in TC patients than in general population, although a relatively higher prevalence in the group of TC patients treated with MKIs. A single patient with advanced TC and SARS-Cov-2 infection during MKIs treatment had a mild COVID-19 and did not require the discontinuation of MKI therapy. In cases of more severe COVID-19, an accurate evaluation from a multidisciplinary team would consider risks and benefits in taking the decision to continue or stop MKI treatment.