This article was accepted into the corpus but its outbound wikilinks were never NER-processed — typical at the deepest BFS hop or when the run's entity cap was reached. No expansion funnel to show.
| Josef Käs | |
|---|---|
| Name | Josef Käs |
| Birth date | 1960s |
| Nationality | German |
| Fields | Biophysics, Cancer Biology, Cell Mechanics |
| Institutions | Rudolf Virchow Center, University of Würzburg; University of Leipzig; National Cancer Institute |
| Known for | Mechanobiology of cancer, cell stiffness as biomarker |
Josef Käs is a German biophysicist and cancer researcher noted for pioneering work on the mechanical properties of cancer cells and the role of cell deformability in metastasis. His interdisciplinary approach bridges biophysics, oncology, cell biology, polymer physics, and nanotechnology to propose mechanistic links between physical properties and malignancy. Käs has led research groups at major European centers and contributed influential experimental techniques and conceptual frameworks that have influenced diagnostics and therapeutic research.
Born in Germany in the 1960s, Käs completed undergraduate and graduate training in physics and biophysics amid the scientific environments of Freie Universität Berlin, Humboldt University of Berlin, and the Max Planck Society network. His doctoral work interfaced with groups at the University of Leipzig and collaborators from the European Molecular Biology Laboratory and the Helmholtz Association, exposing him to techniques from optical tweezers, atomic force microscopy, and polymer rheology. During postdoctoral periods he interacted with laboratories connected to the National Institutes of Health, the European Research Council, and the Rudolf Virchow Center at the University of Würzburg, shaping his trajectory toward cancer cell mechanics.
Käs established independent research programs at the University of Leipzig and later at the University of Würzburg, organizing interdisciplinary teams that included scientists from the Max Planck Institute for Biophysical Chemistry, the German Cancer Research Center (DKFZ), and the Fraunhofer Society. He has collaborated with investigators at the National Cancer Institute, the Karolinska Institutet, University College London, Massachusetts Institute of Technology, and the University of Cambridge on projects spanning single-cell biophysics, microfluidics, and clinical translation. His laboratories developed custom instrumentation integrating concepts from microfluidics, confocal microscopy, laser tweezers, and high-content screening to probe mechanical phenotypes of tumor cells. Käs has served on panels of the European Molecular Biology Organization and advisory boards for initiatives funded by the European Commission's Horizon 2020 program and national funding bodies such as the Deutsche Forschungsgemeinschaft.
Käs is best known for demonstrating that malignant transformation and metastatic potential correlate with altered physical properties of cells, particularly reduced stiffness and increased deformability. His work linked alterations in the cytoskeleton—including perturbations of actin, microtubules, and intermediate filaments—to mechanical phenotypes observed in tumor cells from cancers such as breast cancer, pancreatic cancer, prostate cancer, glioblastoma, and melanoma. Employing methods inspired by polymer physics and soft matter physics, he characterized cytoskeletal network behavior analogously to entropic elasticity and viscoelasticity. Käs introduced and advanced biomechanical assays capable of distinguishing circulating tumor cells in models of metastasis and contributed to the conceptualization of mechanical biomarkers alongside molecular markers such as epithelial–mesenchymal transition, E-cadherin, β-catenin, and signaling pathways involving Rho GTPases and PI3K/Akt.
His group integrated findings with extracellular matrix studies focusing on collagen, fibronectin, and hyaluronic acid remodeling, exploring how matrix stiffness and topology influence invasive behavior via mechanotransduction pathways mediated by integrins, focal adhesion kinase, and YAP/TAZ. These interdisciplinary links connected Käs's work to clinical topics including chemoresistance, tumor microenvironment, and diagnostic platforms such as liquid biopsy and circulating tumor cell enrichment.
Käs authored and coauthored papers in journals including Nature Physics, Nature Communications, Cell Reports, Biophysical Journal, PNAS, Physical Review Letters, and Cancer Research. He proposed that a mechanical phenotype—often summarized as "softness"—is a functional hallmark of malignancy complementary to genetic and epigenetic hallmarks defined by authors of The Hallmarks of Cancer framework. Käs's theoretical contributions drew on models from worm-like chain model, reptation theory, and continuum mechanics to explain cytoskeletal remodeling during oncogenic transformation. His group developed quantitative metrics and standardized assays for measuring single-cell deformability and applied them in translational studies involving patient-derived samples from breast cancer patients, colorectal cancer cohorts, and glioma specimens. Collaborations extended his theories to engineered systems combining microfluidic devices, lab-on-a-chip diagnostics, and machine learning methods from groups at ETH Zurich and Imperial College London.
Käs has received recognition from national and international bodies including awards and fellowships administered by the Deutsche Forschungsgemeinschaft, the European Research Council (collaborative grants), and prizes from scientific societies such as the German Biophysical Society and the European Association for Cancer Research. He has been invited to speak at symposiums organized by entities including the Gordon Research Conferences, the Cold Spring Harbor Laboratory, the American Association for Cancer Research, and the European Society for Cell Biology. His laboratory's translational patents and spin-off initiatives have engaged stakeholders from the Berlin Institute of Health and regional technology transfer offices.
Käs is noted for mentoring multidisciplinary scientists who have taken positions across academia and industry at institutions including the Max Planck Gesellschaft, University of Oxford, Stanford University, and biotechnology companies in the Biotech Triangle. His legacy includes methodological standards in single-cell mechanics, influence on diagnostic concepts for circulating tumor cell detection, and a body of work that connects physical principles with clinical oncology practice. Ongoing citations in literature from groups at the Broad Institute, Scripps Research, and other translational centers attest to the continuing relevance of his contributions to mechanobiology and cancer research.
Category:German biophysicists Category:Cancer researchers