Tight Junction Proteins as Therapeutic Targets to Treat Liver Fibrosis and Hepatocellular Carcinoma.

In the last decade tight junction proteins exposed at the surface of liver or cancer cells have been uncovered as mediators of liver disease biology: Claudin-1 and Occludin are host factors for hepatitis C virus entry and Claudin-1 has been identified as a driver for liver fibrosis and hepatocellular carcinoma (HCC). Moreover, Claudins have emerged as therapeutic targets for liver disease and HCC. CLDN1 expression is upregulated in liver fibrosis and HCC. Monoclonal antibodies (mAbs) targeting Claudin-1 have completed preclinical proof-of-concept studies for treatment of liver fibrosis and HCC and are currently in clinical development for advanced liver fibrosis. Claudin-6 overexpression is associated with an HCC aggressive phenotype and treatment resistance. Claudin-6 mAbs or chimeric antigen receptor-T cells therapies are currently being clinically investigated for Claudin-6 overexpressing tumors. In conclusion, targeting Claudin proteins offers a novel clinical opportunity for the treatment of patients with advanced liver fibrosis and HCC.

Characteristics and outcomes of immunotherapy-related liver injury in patients with hepatocellular carcinoma versus other advanced solid tumours.

BACKGROUND & AIMS: Immune-related liver injury (irLI) is commonly observed in patients with cancer treated with immune checkpoint inhibitors (ICIs). We aimed to compare the incidence, clinical characteristics, and outcomes of irLI between patients receiving ICIs for hepatocellular carcinoma (HCC) vs. other solid tumours. METHODS: Two separate cohorts were included: 375 patients with advanced/unresectable HCC, Child-Pugh A class treated with first-line atezolizumab+bevacizumab from the AB-real study, and a non-HCC cohort including 459 patients treated with first-line ICI therapy from the INVIDIa-2 multicentre study. IrLI was defined as a treatment-related increase of aminotransferase levels after exclusion of alternative aetiologies of liver injury. The incidence of irLI was adjusted for the duration of treatment exposure. RESULTS: In patients with HCC, the incidence of any grade irLI was 11.4% over a median treatment exposure of 4.4 months (95% CI 3.7-5.2) vs. 2.6% in the INVIDIa-2 cohort over a median treatment exposure of 12.4 months (95% CI 11.1-14.0). Exposure-adjusted-incidence of any grade irLI was 22.1 per 100-patient-years in patients with HCC and 2.1 per 100-patient-years in patients with other solid tumours (p <0.001), with median time-to-irLI of 1.4 and 4.7 months, respectively. Among patients who developed irLI, systemic corticosteroids were administered in 16.3% of patients with HCC and 75.0% of those without HCC (p <0.001), and irLI resolution was observed in 72.1% and 58.3%, respectively (p = 0.362). In patients with HCC, rates of hepatic decompensation and treatment discontinuation due to irLI were 7%. Grade 1-2 irLI was associated with improved overall survival only in patients with HCC (hazard ratio 0.53, 95% CI 0.29-0.96). CONCLUSIONS: Despite higher incidence and earlier onset, irLI in patients with HCC is characterised by higher rates of remission and lower requirement for corticosteroid therapy (vs. irLI in other solid tumours), low risk of hepatic decompensation and treatment discontinuation, not negatively affecting oncological outcomes. IMPACT AND IMPLICATIONS: Immune-related liver injury (irLI) is common in patients with cancer receiving immune checkpoint inhibitors (ICIs), but whether irLI is more frequent or it is associated with a worse clinical course in patients with hepatocellular carcinoma (HCC), compared to other tumours, is not known. Herein, we compared characteristics and outcomes of irLI in two prospective cohorts including patients treated with ICIs for HCC or for other oncological indications. irLI is significantly more common and it occurs earlier in patients with HCC, also after adjustment for duration of treatment exposure. However, outcomes of patients with HCC who developed irLI are not negatively affected in terms of requirement for corticosteroid therapy, hepatic decompensation, treatment discontinuation and overall survival.

Prediction of postembolization syndrome after transarterial chemoembolization of hepatocellular carcinoma and its impact on prognosis.

BACKGROUND: Postembolization syndrome (PES) represents the most frequent complication after transarterial chemoembolization (TACE) in patients with HCC. Given the vague definition as a symptom complex comprising abdominal pain, fever, and nausea, PES is diagnosed in heterogeneous patient cohorts with symptoms ranging from mild pain to severe deterioration of their general condition. This study aimed to evaluate predictive factors and the prognostic impact of PES with regard to different severity grades. METHODS: A total of 954 patients treated with TACE for HCC at the University Medical Centres Mainz and Freiburg were included in this study. PES disease severity was graded as mild, moderate, or severe according to a predefined combination of symptoms. Logistic regression models were used to identify independent predictors of PES. The prognostic impact of PES was evaluated by competing risk analyses considering liver transplantation as a competing risk. RESULTS: PES occurred in 616 patients (64.5%), but only 56 patients (5.9%) had severe PES, defined as moderate to severe abdominal pain requiring opioids in combination with fever and nausea. The largest tumor diameter was the strongest independent predictor of PES (OR = 1.21, 95% CI = 1.13-1.28), and severe PES (OR = 1.23, 95% CI = 1.14-1.33, p < 0.0001). Presence of liver cirrhosis was protective against PES (OR = 0.48, 95% CI = 0.27-0.84, p = 0.01). Furthermore, PES was independently associated with an impaired disease control rate (OR = 0.33, 95% CI = 0.16-0.69, p = 0.003) and severe PES with poor overall survival (subdistribution HR = 1.53, 95% CI = 0.99-2.36, p = 0.04). CONCLUSIONS: Tumor size and absence of liver cirrhosis are predictors of severe PES and associated with impaired prognosis in HCC patients after TACE.

Tight Junction Protein Signaling and Cancer Biology.

Tight junctions (TJs) are intercellular protein complexes that preserve tissue homeostasis and integrity through the control of paracellular permeability and cell polarity. Recent findings have revealed the functional role of TJ proteins outside TJs and beyond their classical cellular functions as selective gatekeepers. This is illustrated by the dysregulation in TJ protein expression levels in response to external and intracellular stimuli, notably during tumorigenesis. A large body of knowledge has uncovered the well-established functional role of TJ proteins in cancer pathogenesis. Mechanistically, TJ proteins act as bidirectional signaling hubs that connect the extracellular compartment to the intracellular compartment. By modulating key signaling pathways, TJ proteins are crucial players in the regulation of cell proliferation, migration, and differentiation, all of which being essential cancer hallmarks crucial for tumor growth and metastasis. TJ proteins also promote the acquisition of stem cell phenotypes in cancer cells. These findings highlight their contribution to carcinogenesis and therapeutic resistance. Moreover, recent preclinical and clinical studies have used TJ proteins as therapeutic targets or prognostic markers. This review summarizes the functional role of TJ proteins in cancer biology and their impact for novel strategies to prevent and treat cancer.

Treatment of HCC with claudin-1-specific antibodies suppresses carcinogenic signaling and reprograms the tumor microenvironment.

BACKGROUND & AIMS: Despite recent approvals, the response to treatment and prognosis of patients with advanced hepatocellular carcinoma (HCC) remain poor. Claudin-1 (CLDN1) is a membrane protein that is expressed at tight junctions, but it can also be exposed non-junctionally, such as on the basolateral membrane of the human hepatocyte. While CLDN1 within tight junctions is well characterized, the role of non-junctional CLDN1 and its role as a therapeutic target in HCC remains unexplored. METHODS: Using humanized monoclonal antibodies (mAbs) specifically targeting the extracellular loop of human non-junctional CLDN1 and a large series of patient-derived cell-based and animal model systems we aimed to investigate the role of CLDN1 as a therapeutic target for HCC. RESULTS: Targeting non-junctional CLDN1 markedly suppressed tumor growth and invasion in cell line-based models of HCC and patient-derived 3D ex vivo models. Moreover, the robust effect on tumor growth was confirmed in vivo in a large series of cell line-derived xenograft and patient-derived xenograft mouse models. Mechanistic studies, including single-cell RNA sequencing of multicellular patient HCC tumorspheres, suggested that CLDN1 regulates tumor stemness, metabolism, oncogenic signaling and perturbs the tumor immune microenvironment. CONCLUSIONS: Our results provide the rationale for targeting CLDN1 in HCC and pave the way for the clinical development of CLDN1-specific mAbs for the treatment of advanced HCC. IMPACT AND IMPLICATIONS: Hepatocellular carcinoma (HCC) is associated with high mortality and unsatisfactory treatment options. Herein, we identified the cell surface protein Claudin-1 as a treatment target for advanced HCC. Monoclonal antibodies targeting Claudin-1 inhibit tumor growth in patient-derived ex vivo and in vivo models by modulating signaling, cell stemness and the tumor immune microenvironment. Given the differentiated mechanism of action, the identification of Claudin-1 as a novel therapeutic target for HCC provides an opportunity to break the plateau of limited treatment response. The results of this preclinical study pave the way for the clinical development of Claudin-1-specific antibodies for the treatment of advanced HCC. It is therefore of key impact for physicians, scientists and drug developers in the field of liver cancer and gastrointestinal oncology.

A monoclonal antibody targeting nonjunctional claudin-1 inhibits fibrosis in patient-derived models by modulating cell plasticity.

Tissue fibrosis is a key driver of end-stage organ failure and cancer, overall accounting for up to 45% of deaths in developed countries. There is a large unmet medical need for antifibrotic therapies. Claudin-1 (CLDN1) is a member of the tight junction protein family. Although the role of CLDN1 incorporated in tight junctions is well established, the function of nonjunctional CLDN1 (njCLDN1) is largely unknown. Using highly specific monoclonal antibodies targeting a conformation-dependent epitope of exposed njCLDN1, we show in patient-derived liver three-dimensional fibrosis and human liver chimeric mouse models that CLDN1 is a mediator and target for liver fibrosis. Targeting CLDN1 reverted inflammation-induced hepatocyte profibrogenic signaling and cell fate and suppressed the myofibroblast differentiation of hepatic stellate cells. Safety studies of a fully humanized antibody in nonhuman primates did not reveal any serious adverse events even at high steady-state concentrations. Our results provide preclinical proof of concept for CLDN1-specific monoclonal antibodies for the treatment of advanced liver fibrosis and cancer prevention. Antifibrotic effects in lung and kidney fibrosis models further indicate a role of CLDN1 as a therapeutic target for tissue fibrosis across organs. In conclusion, our data pave the way for further therapeutic exploration of CLDN1-targeting therapies for fibrotic diseases in patients.

Impact of duodenal-jejunal bypass liner (DJBL) on NAFLD in patients with obesity and type 2 diabetes mellitus.

OBJECTIVES: Non-alcoholic fatty liver disease (NAFLD) represents an excessively rising entity of chronic liver disease and is a leading cause of mortality among patients with metabolic syndrome. The duodenal-jejunal bypass liner (DJBL) is a minimally invasive endoscopic treatment option for patients with obesity and type 2 diabetes (T2DM). Although beneficial effects of DJBL therapy on body weight reduction and glycemic control have been described, the effects of DJBL implantation on NAFLD is unknown. The aim of this study was to to evaluate the effects of DJBL implantation for 6 to 9 months on biochemical and clinical biomarkers of NAFLD in a large cohort of patients. METHODS: The effect of DJBL treatment on biochemical and clinical parameters of NAFLD were assessed in a study cohort of 71 patients with obesity and T2DM. DJBL was implanted for 9 to 12 months and patients were regularly monitored during the implantation period and for a follow-up period of 6 months after explantation. RESULTS: DJBL therapy was associated with a significant decrease in fatty liver index during time of implantation (explantation versus implantation: 93.38 versus 98.22, P < 0.001). Moreover, DJBL implantation was associated with decreases of alanine aminotransferase (29.03 versus 42.29 U/L, P < 0.0001) and cytokeratin-18 fragments (CK18 MF30; 190.6 versus 276 U/L, P < 0.0001), that further remained stable during 6 months after explantation. NAFLD fibrosis and aspartate aminotransferase-to-platelet ratio index (APRI) scores decreased significantly during implantation (-0.83 versus 0.19, P < 0.001, 0.26 versus 0.36, P < 0.0001, respectively). CONCLUSIONS: To our knowledge, this is the first study to demonstrate significant effects of DJBL treatment on biochemical and clinical markers of NAFLD activity. Significant effects of DJBL treatment on NAFLD fibrosis and APRI score further suggests protective effects of DJBL on liver-related morbidity and mortality in patients with obesity and T2DM.

COVID-19 mRNA booster vaccine induces transient CD8+ T effector cell responses while conserving the memory pool for subsequent reactivation.

Immunization with two mRNA vaccine doses elicits robust spike-specific CD8+ T cell responses, but reports of waning immunity after COVID-19 vaccination prompt the introduction of booster vaccination campaigns. However, the effect of mRNA booster vaccination on the spike-specific CD8+ T cell response remains unclear. Here we show that spike-specific CD8+ T cells are activated and expanded in all analyzed individuals receiving the 3rd and 4th mRNA vaccine shots. This CD8+ T cell boost response is followed by a contraction phase and lasts only for about 30-60 days. The spike-specific CD8+ T memory stem cell pool is not affected by the 3rd vaccination. Both 4th vaccination and breakthrough infections with Delta and Omicron rapidly reactivate CD8+ T memory cells. In contrast, neutralizing antibody responses display little boost effect towards Omicron. Thus, COVID-19 mRNA booster vaccination elicits a transient T effector cell response while long-term spike-specific CD8+ T cell immunity is conserved to mount robust memory recall targeting emerging variants of concern.

SARS-CoV-2-specific T-cell epitope repertoire in convalescent and mRNA-vaccinated individuals.

Continuously emerging variants of concern (VOCs) sustain the SARS-CoV-2 pandemic. The SARS-CoV-2 Omicron/B.1.1.529 VOC harbours multiple mutations in the spike protein associated with high infectivity and efficient evasion from humoral immunity induced by previous infection or vaccination. By performing in-depth comparisons of the SARS-CoV-2-specific T-cell epitope repertoire after infection and messenger RNA vaccination, we demonstrate that spike-derived epitopes were not dominantly targeted in convalescent individuals compared to non-spike epitopes. In vaccinees, however, we detected a broader spike-specific T-cell response compared to convalescent individuals. Booster vaccination increased the breadth of the spike-specific T-cell response in convalescent individuals but not in vaccinees with complete initial vaccination. In convalescent individuals and vaccinees, the targeted T-cell epitopes were broadly conserved between wild-type SARS-CoV-2 variant B and Omicron/B.1.1.529. Hence, our data emphasize the relevance of vaccine-induced spike-specific CD8+ T-cell responses in combating VOCs including Omicron/B.1.1.529 and support the benefit of boosting convalescent individuals with mRNA vaccines.

Survival prediction using the Freiburg index of post-TIPS survival (FIPS) in critically ill patients with acute- on chronic liver failure: A retrospective observational study.

Background and aim: Liver cirrhosis in patients treated in the intensive care unit (ICU) is associated with high mortality. Well established scores are useful to allow for assessment of prognosis and support ICU treatment guidance. However, currently used scoring systems often do not reflect the complexity of critically ill patients. Therefore, we tested the newly developed Freiburg index-of post-TIPS survival (FIPS) score in order to assess its potential role for prognostication of cirrhotic patients in the ICU. Methods: A total of 310 patients with liver cirrhosis treated in the ICU between 2010 and 2021 were enrolled in this retrospective observational study. Prognostic factors for mortality and 28-day mortality were assessed. Moreover, using c indices the prognostic discrimination of different prognostic scores was analyzed. Results: The FIPS score allowed to discriminate patients with high ICU mortality and within 28-days after ICU treatment (ICU mortality: 42.2 vs. 59.9%, p = 0.008 and 28-day mortality: 43.3 vs. 74.1%, p < 0.001). However, the FIPS score in its current composition showed no superior prognostic discrimination compared to other established scores. Multivariable analyses identified the FIPS score (HR 1.25 [1.04-1.49], p = 0.015) and lactate at admission (HR 1.07 [1.04-1.09], p < 0.001) as significant predictors of ICU mortality. Lactate at admission substantially improved patient risk stratification within each FIPS risk groups. Conclusion: Similar to other commonly used scores, the FIPS score in its current composition does not allow a sufficiently reliable prognostication of critically ill patients treated in the ICU. However, adding lactate as additional factor to the FIPS score may improve its prognostic ability.

A human liver cell-based system modeling a clinical prognostic liver signature for therapeutic discovery.

Chronic liver disease and hepatocellular carcinoma (HCC) are life-threatening diseases with limited treatment options. The lack of clinically relevant/tractable experimental models hampers therapeutic discovery. Here, we develop a simple and robust human liver cell-based system modeling a clinical prognostic liver signature (PLS) predicting long-term liver disease progression toward HCC. Using the PLS as a readout, followed by validation in nonalcoholic steatohepatitis/fibrosis/HCC animal models and patient-derived liver spheroids, we identify nizatidine, a histamine receptor H2 (HRH2) blocker, for treatment of advanced liver disease and HCC chemoprevention. Moreover, perturbation studies combined with single cell RNA-Seq analyses of patient liver tissues uncover hepatocytes and HRH2+, CLEC5Ahigh, MARCOlow liver macrophages as potential nizatidine targets. The PLS model combined with single cell RNA-Seq of patient tissues enables discovery of urgently needed targets and therapeutics for treatment of advanced liver disease and cancer prevention.

Liver Fibrosis: Mechanistic Concepts and Therapeutic Perspectives.

Liver fibrosis due to viral or metabolic chronic liver diseases is a major challenge of global health. Correlating with liver disease progression, fibrosis is a key factor for liver disease outcome and risk of hepatocellular carcinoma (HCC). Despite different mechanism of primary liver injury and disease-specific cell responses, the progression of fibrotic liver disease follows shared patterns across the main liver disease etiologies. Scientific discoveries within the last decade have transformed the understanding of the mechanisms of liver fibrosis. Removal or elimination of the causative agent such as control or cure of viral infection has shown that liver fibrosis is reversible. However, reversal often occurs too slowly or too infrequent to avoid life-threatening complications particularly in advanced fibrosis. Thus, there is a huge unmet medical need for anti-fibrotic therapies to prevent liver disease progression and HCC development. However, while many anti-fibrotic candidate agents have shown robust effects in experimental animal models, their anti-fibrotic effects in clinical trials have been limited or absent. Thus, no approved therapy exists for liver fibrosis. In this review we summarize cellular drivers and molecular mechanisms of fibrogenesis in chronic liver diseases and discuss their impact for the development of urgently needed anti-fibrotic therapies.

Tight Junction Proteins and the Biology of Hepatobiliary Disease.

Tight junctions (TJ) are intercellular adhesion complexes on epithelial cells and composed of integral membrane proteins as well as cytosolic adaptor proteins. Tight junction proteins have been recognized to play a key role in health and disease. In the liver, TJ proteins have several functions: they contribute as gatekeepers for paracellular diffusion between adherent hepatocytes or cholangiocytes to shape the blood-biliary barrier (BBIB) and maintain tissue homeostasis. At non-junctional localizations, TJ proteins are involved in key regulatory cell functions such as differentiation, proliferation, and migration by recruiting signaling proteins in response to extracellular stimuli. Moreover, TJ proteins are hepatocyte entry factors for the hepatitis C virus (HCV)-a major cause of liver disease and cancer worldwide. Perturbation of TJ protein expression has been reported in chronic HCV infection, cholestatic liver diseases as well as hepatobiliary carcinoma. Here we review the physiological function of TJ proteins in the liver and their implications in hepatobiliary diseases.

Duodenal-Jejunal Bypass Liner (DJBL) Improves Cardiovascular Risk Biomarkers and Predicted 4-Year Risk of Major CV Events in Patients with Type 2 Diabetes and Metabolic Syndrome.

BACKGROUND: The duodenal-jejunal bypass liner (DJBL) represents a novel endoscopic minimally invasive treatment option for obesity-associated type 2 diabetes (T2D), affecting body weight and metabolic control. Until now, the effects of DJBL on cardiovascular risk have never been investigated. METHODS: Between 2012 and 2017, 71 patients with T2D and metabolic syndrome (MS) were recruited for implantation of DJBL for 9-12 months. Within DJBL treatment and a follow-up period of 6 months, patients were analysed for dynamics of cardiovascular biomarkers. Overall cardiovascular risk was estimated by the ADVANCE Risk Engine at time of implantation, explantation and 6 months after explantation of DJBL. RESULTS: DJBL-induced weight loss and improvements in blood sugar control were accompanied by significant decreases of the cardiovascular biomarkers high-sensitive CRP, lipoprotein-associated phospholipase A2 and small dense lipoprotein fraction LDL-4 (p = 0.001, p < 0.001 and p = 0.04, respectively). Estimated overall cardiovascular risk decreased significantly after DJBL implantation and remained stable within 6 months after explantation. CONCLUSIONS: In addition to beneficial effects of DJBL on weight loss, glycaemic control and lipid parameters in patients with MS, this is the first study that could further reveal significant impact on serological cardiovascular biomarkers and estimated CV risk, suggesting putative protective effects of DJBL on CV outcome.

Vitamin D, FOXO3a, and Sirtuin1 in Hashimoto's Thyroiditis and Differentiated Thyroid Cancer.

Background: Protective effects of vitamin D have been reported in autoimmune and malignant thyroid diseases, though little is known about the underlying mechanism. Sirtuin 1 histon deacethylase (SIRT1) links the vitamin D pathway with regulation of transcription factor FOXO3a, a key player in cell cycle regulation and apoptosis. Aim of the present study was to investigate common single nucleotide polymorphisms (SNP's) in FOXO3a gene in respect to thyroid diseases, as well as to evaluate the hypothesis of Sirtuin1-FOXO3a interaction being a mediator of anti-proliferative vitamin D effects. Methods: The SNP's FOXO3a rs4946936/rs4945816/rs9400239 were genotyped in 257 patients with differentiated thyroid carcinoma (DTC), 139 patients with Hashimoto thyroiditis (HT) and 463 healthy controls (HC). Moreover, T-helper cells of HC and papillary thyroid cancer cell line BCPAP were incubated with 1,25(OH)2D3 and/or SIRT1 inhibitor Ex-527 in order to elucidate SIRT1- dependent vitamin D effects on cell proliferation and FOXO3a gene expression in vitro. Results: Patients with DTC tended to carry more often allele C in FOXO3a rs4946936 in comparison to HC (pcorrected = pc = 0.08). FOXO3a rs9400239T and rs4945816C was more frequent in HT in comparison to HC (pc = 0.02 and pc = 0.01, respectively). In both DTC and HT, we could not find a correlation of FOXO3a SNP's with vitamin D status. However, on in vitro level, 1,25(OH)2D3 showed an anti-proliferative effect in both T-helper cells and BCPAP, that was blocked by SIRT1 inhibition (T-helper cells: p = 0.0059, BCPAP: p = 0.04) and accompanied by elevated FOXO3a gene expression in T-helper cells (p = 0.05). Conclusions: FOXO3a rs9400239T and rs4945816C may constitute risk factors for HT, independent of the vitamin D status.This indicates the implication of FOXO3a in pathogenesis of autoimmune thyroid diseases. The dependency of anti-proliferative vitamin D effects on SIRT1 activity further suggests a key role of vitamin D-SIRT1-FOXO3a axis for protective vitamin D effects.

Ischemic Duodenal Ulceration after Transarterial Chemoembolization for Hepatocellular Carcinoma: A Case Report.

Drug-eluting bead transarterial chemoembolization (DEB-TACE) is a well-established, minimally invasive interventional treatment for nonresectable hepatocellular carcinoma (HCC). Generally, TACE is regarded as safe and effective with a low complication rate. However, remote gastrointestinal ischemia due to the carryover of embolic material into visceral arteries is a rare but serious complication of TACE. In this report, we present a case of duodenal ulceration with contained perforation and severe necrotizing pancreatitis after TACE in a patient with nonresectable HCC and underlying hepatitis C virus associated with Child-Pugh stage B liver cirrhosis. This patient showed, for the first time, complete endoscopic and clinical recovery within 2 months of conservative treatment. Considering the high mortality rate from surgical intervention in all previously reported patients, the significant recovery potential demonstrated by our case suggests conservative treatment with antibiotics and parenteral nutrition combined with close clinical, radiological, and endoscopic monitoring should be considered in all clinically stable patients without signs of peritonism or septic sequelae.

17q12 Deletion Syndrome as a Rare Cause for Diabetes Mellitus Type MODY5.

Context: Maturity-onset diabetes of the young type 5 (MODY5) is caused by mutations of the hepatocyte nuclear factor 1 homeobox ß gene (HNF1B). Although clinical characteristics and therapeutic management of MODY5 are increasingly better defined, adequate consideration of the frequent association of MODY5 with 17q12 deletion syndrome is often missing. Evidence Acquisition: We report two cases of patients with 17q12 deletion syndrome who presented to our clinic. Furthermore, we reviewed the existing literature to improve systematic diagnostic and therapeutic approaches. A PubMed search using the terms 17q12 deletion syndrome, diabetes mellitus type MODY5, and/or HNF1B was performed. Evidence Synthesis: Three hundred sixty-one cases of postnatal 17q12 deletion syndrome were assessed, and details on clinical manifestations, diagnostic approaches, and therapeutic management were reviewed and compared with the two cases at our clinic. Furthermore, data on pathogenic mechanisms and their clinical implications were evaluated. Conclusion: The 17q12 deletion syndrome usually comprises MODY5, structural or functional abnormalities of the kidneys, and neurodevelopmental or neuropsychiatric disorders. A complete deletion of HNF1B can be found in about 50% of patients with MODY5. A wide variety of additional clinical features, including genital and brain malformations, has been reported. Because HNF1B deletions are virtually always part of a 17q12 deletion syndrome and common genetic analyses for evaluation of MODY5 are unable to detect the deletion of a 1.4-Mb chromosomal region, initial attention to the syndromal features at the stage of diagnosis is of considerable importance for establishing correct diagnosis, subsequent therapy, and interdisciplinary patient care.

Ectopic papillary thyroid carcinoma within a thyroglossal duct cyst: A case report.

RATIONALE: Ectopic thyroid carcinoma within a thyroglossal duct cyst (TGDCCa) is an extremely rare entity. Thus, there is no unified appropriate therapeutic strategy, and individual approaches are controversial. PATIENTS CONCERNS: We report the case of a 21-year old woman who underwent Sistrunk procedure for a thyroglossal duct cyst (TGDC). DIAGNOSES: During histological evaluation of the resected TGDC a papillary thyroid carcinoma was found. INTERVENTIONS: Due to a tumor size of 1cm and proximity to the surgical border, Sistrunk procedure was extended by total thyroidectomy, followed by radioiodine ablation. OUTCOMES: Except of minimal follicular hyperplasia, the histological examination of the resected thyroid gland was unsuspicious. LESSONS: Therapeutic management of TGDCCa is of interdisciplinary debate due to relative infrequence of the disease and consequently lack of unified therapeutic guidelines. We suggest a personalized therapeutic approach adjusted to individual risk stratification. In young patients with small tumor size and with confirmation of TGDCCa representing the primary tumor, Sistrunk procedure alone may reflect adequate treatment. In all other cases, total thyroidectomy and radioiodine ablation should be evaluated. Overall TGDCCa have an excellent prognosis with a 5-year survival rate of more than 90%.