Achim Weber

Background: Biliary Tract Cancers (BTCs) are difficult‐to‐treat malignancies with limited therapeutic options and dismal prognosis. Upfront comprehensive genomic profiling (CGP) is recommended for advanced BTC to identify actionable alterations, but its real‐world implementation remains underexplored. Methods: In 2019, we implemented upfront CGP for advanced BTC at our institution. Molecular profiling results were reviewed within our institutional molecular tumor board when clinically applicable. Patients were followed throughout their disease course. Results: A total of 80 patients with locally unresectable ( n = 14) or metastatic ( n = 66) BTC underwent CGP. Testing was performed on cytology material (6/80), tumor biopsies (38/80), or surgical specimens (36/80). In 59/80 cases (73.8%) testing was carried out prior to the beginning of palliative first‐line treatment. In 42/80 (52.5%) cases, at least one clinically actionable genomic alteration was identified. The most frequent actionable alterations involved IDH1 (13.8%), FGFR2 (8.8%), ERBB2 (HER2) (5.0%), KRAS G12C (2.5%), and BRAF (1.3%). Alterations in DNA damage response genes were detected in 11/80 tumors, and 3/80 were dMMR/MSI‐H. FGFR2 and IDH1 mutations were detected in ICC only, while HER2 alterations were more commonly detected in ECC and GBC. 11/42 patients with a clinically actionable alteration received targeted treatment during the disease course (1 first‐line, 10 later lines). Among patients with an evaluable preceding systemic treatment line, treatment duration was longer with molecularly matched treatment than with the immediately preceding treatment line ( p = 0.0391). 2/14 patients with initially unresectable BTC achieved secondary resectability during molecularly matched treatment. Conclusion: Upfront CGP is feasible in routine clinical practice and identifies clinically actionable alterations in a substantial proportion of patients with advanced BTC. However, only a subset received molecularly matched treatment, highlighting a gap between molecular actionability and treatment implementation. Timely access to matched therapies remains critical to the clinical utility of precision oncology in BTC.

Introduction: During routine examination of specimens from patients with steatotic liver disease (SLD), we repeatedly observed a peculiar phenomenon characterized by obstruction of the hepatic sinusoids by lipid vacuoles (lipidic obstruction of sinusoids, LOS). These changes were reminiscent of pseudopeliotic steatosis (PPS), a complication following liver transplantation (LT), but notably occurred outside this context. The aim of our study was to identify diagnostic indicators for LOS and to determine its clinical significance. Methods: Liver specimens routinely sent to our institute between 2019 and 2024 with SLD were examined for LOS. The extracellular nature of the fat and the compression of the sinusoids were demonstrated by ancillary stains (Gomori, CD68, collagen IV). The extent of the LOS was quantified by measuring the area and maximum diameter of fat lakes. The clinical course of patients with LOS was retrospectively evaluated and correlated with the histological findings. Results: LOS was observed in eight patients, ranging from focal to very extensive extracellular fat. The diagnosis was based on routine histology, supplemented by collagen IV stain highlighting double contours of sinusoids. The morphological findings suggested that lipidic obstruction of the hepatic sinusoids was a key pathophysiological factor. LOS was associated with liver necrosis and activation of macrophages. Patients with LOS exhibited a variable clinical course, ranging from subclinical to severe, including LT or even death. The extent of fat lakes correlated with the severity of the clinical course. Conclusions: We suggest the term LOS for a particular pattern of liver damage that can occur in SLD outside the transplantation setting and may lead to impaired hepatic blood flow. LOS is associated with a variable clinical presentation, ranging from subclinical to fatal. Clinicians and pathologists should be aware of this complication of SLD, which is diagnosed by liver histology.

Hepatocellular carcinoma (HCC) is the fastest growing cause of cancer-related mortality and there are limited therapies ¹ . Although endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) are implicated in HCC, the involvement of the UPR transducer ATF6α remains unclear ² . Here we demonstrate the function of ATF6α as an ER-stress-inducing tumour driver and metabolic master regulator restricting cancer immunosurveillance for HCC, in contrast to its well-characterized role as an adaptive response to ER stress ³ . ATF6α activation in human HCC is significantly correlated with an aggressive tumour phenotype, characterized by reduced patient survival, enhanced tumour progression and local immunosuppression. Hepatocyte-specific ATF6α activation in mice induced progressive hepatitis with ER stress, immunosuppression and hepatocyte proliferation. Concomitantly, activated ATF6α increased glycolysis and directly repressed the gluconeogenic enzyme FBP1 by binding to gene regulatory elements. Restoring FBP1 expression limited ATF6α-activation-related pathologies. Prolonged ATF6α activation in hepatocytes triggered hepatocarcinogenesis, intratumoural T cell infiltration and nutrient-deprived immune exhaustion. Immune checkpoint blockade (ICB) ⁴ restored immunosurveillance and reduced HCC. Consistently, patients with HCC who achieved a complete response to immunotherapy displayed significantly increased ATF6α activation compared with those with a weaker response. Targeting Atf6 through germline ablation, hepatocyte-specific ablation or therapeutic hepatocyte delivery of antisense oligonucleotides dampened HCC in preclinical liver cancer models. Thus, prolonged ATF6α activation drives ER stress, leading to glycolysis-dependent immunosuppression in liver cancer and sensitizing to ICB. Our findings suggest that persistently activated ATF6α is a tumour driver, a potential stratification marker for ICB response and a therapeutic target for HCC.

Two decades after the initial report on increased micronuclei in human chronic liver disease (CLD) and hepatocellular carcinoma (HCC), their role in HCC development is still poorly understood. Here, we show that micronuclei in hepatocytes trigger a hepatic immune response and promote HCC development via an increased level of extrachromosomal circular DNA (eccDNA). Livers of a CLD model ( Mcl1 ^Δhep mice) show increased micronuclei and eccDNA levels. Circular sequencing confirms higher eccDNA levels in micronuclei compared to primary nuclei. The nuclei-segregated DNA fiber (NuSeF) assay we developed demonstrates that micronuclei are more susceptible to replication stress, exhibiting increased replication fork slowing. Comparing different murine liver disease models reveals that high eccDNA correlates with an increased tumor incidence. eccDNA is a strong immunostimulant and promotes a cross-talk between hepatocytes and immune cells through the cGAS-STING pathway. Deletion of Sting1 in Mcl1 ^Δhep mice reduces immune cell chemotaxis and tumor incidence. Our findings suggest that eccDNA from micronuclei mediates inflammation-driven liver carcinogenesis in CLD.

Two decades after the initial report on increased micronuclei in human chronic liver disease (CLD) and hepatocellular carcinoma (HCC), their role in HCC development is still poorly understood. Here we show that micronuclei in hepatocytes trigger hepatic immune response and promote HCC development via an increased level of extrachromosomal circular DNA (eccDNA). Livers from a CLD model ( Mcl1 ^Δhep mice) show increased micronuclei in parallel to eccDNA. Circular sequencing confirms higher eccDNA levels in micronuclei compared to primary nuclei. We developed nuclei-segregated DNA fiber (NuSeF) assay to show that micronuclei are more susceptible to replication stress, showing increased replication fork slowing. By comparing different murine liver disease models, high eccDNA is correlated with increased tumor incidence. EccDNA is a strong immunostimulant and promotes a crosstalk between hepatocytes and immune cells through the cGAS-STING pathway. Deletion of Sting1 in Mcl1 ^Δhep mice reduces immune cell chemotaxis, as well as tumor incidence. Our findings suggest that eccDNA from micronuclei mediates inflammation-driven liver carcinogenesis in CLD.

Thyroid nodules are a widespread phenomenon, with follicular cell-derived thyroid tumors being the most prevalent type of endocrine tumor, spanning from benign through low grade malignant to aggressive neoplasms with dismal prognosis. In clinical practice, histopathological criteria are primarily used to determine malignancy and aggressiveness. Therefore, accurate classification may result in surgical procedures for diagnostic reasons, associated with an imbalanced risk/benefit ratio. In recent years, the use of integrated proteomic approaches has proven valuable in expanding the molecular understanding of thyroid neoplasms, with implications in classification, yet remains understudied in divergent thyroid nodules. Here we show the delineation of subtype-specific and malignancy-dependent molecular characteristics through integrative proteomic and phosphoproteomic analysis of 53 human thyroid tissues, encompassing five frequent benign and malignant tumors. We found that the (phospho)-proteomic profiles enable a clear stratification of malignant and benign thyroid tissues. The method also performs well in delineating follicular adenoma (FA) and follicular thyroid carcinoma (FTC) samples. Beside the dysregulation of cell cycle control, apoptosis, and metabolic reprogramming associated with tumor development and malignancy, we further report increased alterations within the well-established oncogenic RAS/BRAF/MAPK and AKT/MTOR signaling pathways, which, contrary to the prevailing paradigm, did not clearly differentiate between FTC and papillary thyroid carcinoma (PTC). In addition, activities of ATM, PLK2-3, and GRK5-6 kinases were predicted to be strongly upregulated in malignant subtypes. Together, this study provides an in-depth insight into molecular changes in different thyroid tumor subtypes. These findings highlight the potential of integrated proteomic approaches to refine our understanding of complex diseases like cancer. As such, they offer a pathway to more precise diagnostic and personalized treatment strategies.