Hereditary cancer syndromes are among the most common inherited disorders and contribute to nearly 10% of solid tumours. While genetic testing is now central to diagnosis, surveillance, and cascade prevention, its impact is constrained by the persistent challenge of variants of uncertain significance (VUS), which comprise almost 40% of reported hereditary cancer syndrome-associated variants in ClinVar. These unresolved classifications undermine the interpretive power of testing, limiting its translational and preventive potential. In this review, we examine the foundations of variant interpretation, the role of expert-guided specifications, and emerging methods for VUS reclassification, including population-level data, RNA- and protein-based functional assays, computational predictors, and long-read sequencing. We further highlight how systematic re-evaluation structures and curation infrastructures translate new evidence into clinical practice. We conclude with an outlook on future directions to reduce the burden of VUS and increase the clinical utility of hereditary cancer syndrome testing.

Background Human brain organoids (BOs) are important models for studying early brain development and neurological disorders. While techniques for creating BOs are advancing, they remain developmental structures. Therefore, when human BOs are used to studying glioma-host interactions, the tumor behavior may be influenced by the BO-developmental microenvironment. Here, we describe the maturation of rat brain organoids (rBOs) into fully differentiated BOs and demonstrate their value as a model for studying glioblastoma (GB)-host interactions and their use in testing therapeutic interventions.Materials and Methods rBOs were obtained from fetal cortical brains on the 18th day of gestation. Transcriptomic, proteomic, and metabolomic analyses determined their differentiation into maturity. Their developmental trajectory was compared to human BOs derived from induced pluripotent stem cells as well as to rat brain development. Tumor-rBO interactions, including invasion parameters and therapeutic interactions, were studied using 5 human GB models.Results The rBOs develop into organized structures with myelinated neurons, oligodendrocytes, synapses, and glial cells, mirroring the rat brain development. GB invasion in rBOs matched those observed in orthotopic xenografts, enabling real-time assessment of invasion metrics: cellular heterogeneity, single-cell invasion speed, and tumor progression. The BOs had a strong impact on GB transcriptional activity and can be used to study therapeutic interventions. The rBO differentiation status influenced GB invasion capacity.Conclusions The rBOs serve as an effective target brain structure for studying GB invasion parameters and for evaluating therapeutic interventions. Their rapid development into mature brain tissue makes rBOs a valuable brain avatar system for studying tumor-host interactions.

Germline genetic testing practices for hereditary cancer vary across the European Reference Network on Genetic Tumour Risk Syndromes (ERN GENTURIS) member countries. We surveyed experts in genetic testing from 20 EU member countries and Norway to assess multi-gene panel usage, availability of genome-wide sequencing, first-tier testing approaches, implementation of polygenic risk scores, and the roles of non-genetic healthcare professionals. National experts and members of the ERN GENTURIS completed a structured questionnaire covering founder germline pathogenic variants (gPV) testing, panel testing for common genetic tumour risk syndromes, use of whole-exome sequencing (WES) and whole-genome sequencing, polygenic risk score implementation, use of formalin-fixed paraffin-embedded tumour samples, laboratory accreditation, and the clinical roles of physicians, genetic counselors and nurses. Significant inter-country heterogeneity was observed. Most countries rely on next-generation sequencing (NGS) multi-gene panels. Founder gPV testing is first-line in a few high-prevalence populations (e.g., BRCA1/2 founders). All 21 countries offer NGS panel tests for hereditary breast and ovarian cancer, and ≥19 countries do so for colorectal and prostate cancers. However, NGS panel size and gene composition exhibit substantial variability. WES is available in 12 countries on a routine basis. Most countries implemented genetic testing on stored tumour tissue from deceased patients. In all countries, clinical geneticists can order germline genetic tests, and in 9 countries, any physician can do so. These findings show differences in accessibility to germline genetic testing of hereditary cancer in Europe. We propose EU-wide guidance via pathways, standards of care, and sharing of best practices to further optimize access to hereditary cancer genetic molecular diagnostics.

Abstract Glioblastoma is a highly aggressive brain tumour with poor prognosis, whose aetiology, progression, and therapeutic resistance remain incompletely understood. While the microbiota–gut–brain axis has emerged as a key regulator of neurological disorders, its role in glioblastoma biology and treatment response is still largely unexplored. Using a clinically relevant immunocompetent murine model combining glioblastoma stem cell implantation, dextran sodium sulfate-induced gut inflammation, and a full Stupp-like therapeutic protocol, we investigated bidirectional gut–brain communication in glioblastoma. Tumour growth and recurrence were monitored by bioluminescence imaging, tumour transcriptomic profiles were analysed by RNA sequencing, and brain and colon tissues were subjected to histological and molecular analyses. Gut microbiota composition was assessed by 16S rRNA sequencing, while systemic metabolites and cytokines were quantified in plasma. Cross-compartment association bioinformatic analyses were performed to correlate multi-organ readouts. Gut inflammation enhanced glioblastoma growth and promoted tumour recurrence following therapy. Tumour progression was associated with increased infiltration of immunosuppressive macrophages, whereas recurrence correlated with elevated oxidative DNA damage. Remarkably, glioblastoma exerted systemic immunomodulatory effects, attenuating intestinal and systemic inflammatory responses, and induced profound remodelling of gut microbiota composition and predicted metabolic function, including enrichment of Akkermansia and depletion of Lactobacillus . Systemic metabolic profiling was investigated as a route of communication within the gut-brain axis and revealed adaptations in DSS-treated mice associated with tumour burden and therapeutic response. Multi-compartment correlation and multivariable association analyses identified specific bacterial genera and circulating metabolites associated with tumour volume, intestinal inflammation, and genomic instability. These findings uncover a dynamic, bidirectional microbiota–gut–brain axis in glioblastoma and identify intestinal inflammation as a critical determinant of tumour progression and therapeutic outcome. Targeting gut disturbances and microbiota-associated metabolic pathways may represent novel strategies to modulate glioblastoma aggressiveness and treatment response.

Drug resistance of metastatic colorectal cancer (mCRC) remains a major therapeutic challenge. Screening patient-derived tumor cells with diverse compounds in 3D models may overcome the limitations of genomics-based drug response predictions. We describe a personalized functional profiling (PFP) approach in mCRC using patient-derived spheroids (PDS) and assess its utility in predicting drug responses. PDS were established from twelve patients’ tumors and validated by immunohisto(cyto)chemistry and genomic sequencing. Forty-two small molecule anti-cancer drugs, along with five standard-of-care (SOC) drugs in CRC were screened as single agents or in combination, and cell viability was measured using calcein staining or ATP-based assay. Ex vivo results were compared with clinical treatment responses. PDS closely mirrored histopathological and genetic features of the original tumors, supporting their use in PFP. Sensitivity to anti-EGFR drugs distinguished responsive from resistant patients and revealed candidates for anti-ERBB2 therapy, whereas anti-VEGFR screening failed to recapitulate clinical outcomes. SOC drug screening results correlated with clinical outcomes or tumor genetic features in a subset of PDS. This work underscores the predictive value of PFP, its complementarity with genomic sequencing, and the need for refinement to enhance its clinical applicability.

Europe’s Beating Cancer Plan is a substantial European Union (EU) investment into cancer prevention and treatment. Integration of genetic services towards personalised cancer prevention and care is a flagship of this plan. Genetic counselling is critical to this integration, facilitating informed patient decision making and improved clinical management. However, growing demands for genetic testing and concurrently increasing workforce shortages necessitate new strategies to equitably ensure sustainable access to counselling across the EU. This project aimed to inform future European activities by identifying priority European strategies for addressing common European genetic literacy, workforce, and reimbursement barriers to genetic counselling in cancer noted in prior work. A Delphi survey was conducted, with genetics, oncology, and patient stakeholders invited from all EU Member States. The response rate was 62% (124 total invitations). Over three phases, 77 participants – 28 geneticists; 14 oncologists; 18 genetic counsellors; 16 patient representatives; 1 otherwise qualified expert – rated 19 strategies according to their Importance, Urgency, and Feasibility and selected their top three priority strategies. Five strategies met pre-defined consensus thresholds and received a clear plurality of priority ratings: (1) EU-wide genetic counsellor recognition; (2) Including genetics expertise in oncology guideline creation; (3) Shared EU genetic counsellor registration/education with legal weight; (4) Mandatory counselling reimbursement when clinical guidelines are met; (5) Mandatory inclusion of genetics in oncology fellowship/continuing education. Results provide a roadmap of European actions which promise to sustainably improve access to genetic counselling in cancer care. Upcoming and ongoing EU projects promise to advance their implementation.

Background Epithelial neuroendocrine neoplasms (NENs) are a rare and heterogeneous group of malignancies with limited treatment options. Comprehensive molecular characterization may reveal novel therapeutic opportunities for these clinically challenging tumors. Methods Within a nationwide precision oncology program, we performed whole-genome/exome and transcriptome sequencing in 168 patients with a diagnosis of advanced NEN from diverse anatomic origins, followed by evaluation of real-world outcomes associated with molecularly guided interventions. Findings Our analysis revealed substantial molecular heterogeneity across advanced NENs, including distinct genetic profiles between low-grade and high-grade tumors, as well as alterations specific to particular tissues of origin. Candidate therapeutic targets included elevated tumor mutational burden induced by temozolomide exposure, rare actionable kinase mutations, overexpression of targetable antigens, and signatures of homologous recombination deficiency, providing a rationale for immune checkpoint blockade, kinase inhibitors, antibody-drug conjugates, poly(ADP-ribose) polymerase (PARP) inhibitors, and platinum-based therapies, respectively. Overall, 144 patients (85.7%) received molecularly guided treatment recommendations, of which 85 were implemented in 57 patients (39.6%). Among 68 evaluable therapy outcomes, 47 (69.1%) demonstrated clinical benefit (objective response, n = 25; disease stabilization, n = 22). At the patient level, 34 of the 57 treated (59.6%) experienced clinical benefit from at least one therapy (objective response, n = 18; disease stabilization, n = 16). Conclusions Comprehensive genomic and transcriptomic profiling identified distinct molecular alteration patterns and therapeutic vulnerabilities among different classes of epithelial NENs from various tissues, warranting further investigation in anatomic-site-specific studies. Our outcome data underscore the clinical utility of broad molecular profiling in patients with advanced NENs lacking further standard treatment options. Funding Funding for the study was institutional.

Genetic tumor risk syndromes (genturis) contribute substantially to the overall cancer burden and provide opportunities for early detection, prevention, and individualized treatment. Yet, many affected individuals remain undiagnosed due to restrictive testing criteria and challenges in variant interpretation. This review summarizes recent advances in the diagnostic evaluation of genturis. We trace the evolution from single‐gene testing to multigene panel testing, highlighting gains in diagnostic yield alongside the growing prevalence of uncertain and incidental findings. We then describe emerging functional approaches such as RNA sequencing and proteomics that generate molecular evidence to refine variant classification. Next, we outline how long‐read sequencing overcomes technical limitations in complex genomic regions. Finally, we discuss practical aspects of clinical implementation, including reporting practices, workflow integration, and professional education, and propose strategies to improve diagnostic accuracy, efficiency, and equitable access to testing.

Interpreting variants of uncertain significance (VUS) in mismatch repair (MMR) genes remains a major challenge in managing Lynch syndrome and other hereditary cancer syndromes. This review outlines recommended VUS classification procedures, encompassing foundational and specialized methodologies tailored for MMR genes by expert organizations, including InSiGHT and ClinGen’s Hereditary Colorectal Cancer/Polyposis Variant Curation Expert Panel (VCEP). Key approaches include: (1) functional data, encompassing direct assays measuring MMR proficiency such as in vitro MMR assays, deep mutational scanning, and MMR cell-based assays, as well as techniques like methylation-tolerant assays, proteomic-based approaches, and RNA sequencing, all of which provide critical functional evidence supporting variant pathogenicity; (2) computational data/tools, including in silico meta-predictors and models, which contribute to robust VUS classification when integrated with experimental evidence; and (3) enhanced variant detection to identify the actual causal variant through whole-genome sequencing and long-read sequencing to detect pathogenic variants missed by traditional methods. These strategies improve diagnostic precision, support clinical decision-making for Lynch syndrome, and establish a flexible framework that can be applied to other OMIM-listed genes.

As multigene panel testing is becoming routine in clinical care, there are recommendations at national and international level, as to which genes should be analyzed in the context of a hereditary breast and ovarian cancer (HBOC). However, the individual composition of gene panels offered by testing laboratories vary, resulting in a different variant diagnostic rate. Therefore, we performed a retrospective NGS dataset analysis of suspected HBOC patients who had been tested at different German diagnostic laboratories that are part of the NASGE network. We collected 29,317 HBOC datasets and compared the diagnostic yield applying the most common panel recommendations and an internal HBOC gene panel. Additionally, we analyzed the data concerning other potential tumor risk syndromes (TRS) not caused by pathogenic variants in the core panel genes. At least one pathogenic variant causative for an autosomal-dominant TRS was identified in 4235 datasets, resulting in an overall diagnostic yield of 14.4 %. The diagnostic yield of pathogenic variants varied depending on the applied HBOC panel (between 5 and 26 genes) from 9.0 % to 13.8 % with the internal HBOC panel having a yield of 12.7 %. Notably, in about 1 % of cases, a pathogenic variant outside the established HBOC core genes was identified, indicating the presence of other TRS. These results are consistent with previous observations that a significant proportion of patients with HBOC predisposition were not detected by the guideline-based gene panels and suggest that expanded diagnostics compared to currently recommended multigene panels may identify additional patients at high risk for developing cancer.

Glioblastoma is one of the most treatment-resistant and lethal cancers, with a subset of self-renewing brain tumour stem cells (BTSCs), driving therapy resistance and relapse. Here, we report that mubritinib effectively impairs BTSC stemness and growth. Mechanistically, bioenergetic assays and rescue experiments showed that mubritinib targets complex I of the electron transport chain, thereby impairing BTSC self-renewal and proliferation. Gene expression profiling and Western blot analysis revealed that mubritinib disrupts the AMPK/p27Kip1 pathway, leading to cell-cycle impairment. By employing in vivo pharmacokinetic assays, we established that mubritinib crosses the blood-brain barrier. Using preclinical patient-derived and syngeneic models, we demonstrated that mubritinib delays glioblastoma progression and extends animal survival. Moreover, combining mubritinib with radiotherapy or chemotherapy offers survival advantage to animals. Notably, we showed that mubritinib alleviates hypoxia, thereby enhancing ROS generation, DNA damage, and apoptosis in tumours when combined with radiotherapy. Encouragingly, toxicological and behavioural studies revealed that mubritinib is well tolerated and spares normal cells. Our findings underscore the promising therapeutic potential of mubritinib, warranting its further exploration in clinic for glioblastoma therapy.

Background Somatic and germline genetic alterations are significant drivers of cancer. Increasing integration of new technologies which profile these alterations requires timely, equitable and high-quality genetic counselling to facilitate accurate diagnoses and informed decision-making by patients and their families in preventive and clinical settings. This article aims to provide an overview of genetic counselling legislation and practice across European Union (EU) Member States to serve as a foundation for future European recommendations and action.Methods National legislative databases of all 27 Member States were searched using terms relevant to genetic counselling, translated as appropriate. Interviews with relevant experts from each Member State were conducted to validate legislative search results and provide detailed insights into genetic counselling practice in each country.Results Genetic counselling is included in national legislative documents of 22 of 27 Member States, with substantial variation in legal mechanisms and prescribed details (i.e. the 'who, what, when and where' of counselling). Practice is similarly varied. Workforce capacity (25 of 27 Member States) and genetic literacy (all Member States) were common reported barriers. Recognition and/or better integration of genetic counsellors and updated legislation and were most commonly noted as the 'most important change' which would improve practice.Conclusions This review highlights substantial variability in genetic counselling across EU Member States, as well as common barriers notwithstanding this variation. Future recommendations and action should focus on addressing literacy and capacity challenges through legislative, regulatory and/or strategic approaches at EU, national, regional and/or local levels.