117 A new study suggests that a protein known as HOXB13 could hold the key to more accurate and accessible diagnoses of spinal cord tumours, potentially replacing expensive DNA profiling in many cases. Published in Acta Neuropathologica, the research reveals that strong nuclear expression of HOXB13 is a reliable indicator of myxopapillary ependymoma, a type of spinal tumour that can be difficult to distinguish from similar cancers under the microscope. The study analysed 143 spinal tumours, including 54 initially diagnosed as myxopapillary ependymoma and 46 as spinal ependymoma. Using immunohistochemical staining, researchers found that HOXB13 was strongly expressed in all confirmed cases of myxopapillary ependymoma but not in spinal ependymoma. This protein-based method showed perfect correlation with DNA methylation profiling, a technique that maps chemical changes to DNA and is currently considered the gold standard for tumour classification. What makes this development significant is its practical potential. DNA methylation profiling, though accurate, is not widely available, especially in lower-income regions. In contrast, testing for HOXB13 expression through immunohistochemistry is already standard practice in many pathology labs, making it a far more accessible diagnostic tool. While the protein is also found in rare cauda equina neuroendocrine tumours, these have distinct features that pathologists can identify through other markers. This means that HOXB13 remains highly specific for identifying myxopapillary ependymoma when used correctly. Beyond the practical benefits, the study also offers insights into the biological mechanisms behind the protein’s expression. Researchers found that the difference in HOXB13 expression between tumour types is not due to genetic changes like gene amplification but is likely driven by DNA methylation. This epigenetic regulation means that the gene is switched on or off depending on how its DNA is chemically modified, a process that could be further explored for therapeutic implications. The implications for diagnosis are immediate. In cases where tumour tissue is ambiguous, HOXB13 staining could serve as a first-line approach, guiding treatment decisions more quickly and cost-effectively. In cases where the staining is unclear, follow-up DNA methylation analysis could still be used. Experts believe this marker could reshape routine diagnostics for spinal ependymal tumours. For patients, it could mean faster diagnoses and more accurate treatments. For clinicians, it offers a practical solution to a longstanding diagnostic challenge. The findings also underscore the growing importance of integrating molecular tools with traditional pathology. As researchers continue to identify such biomarkers, the hope is that diagnosis will become not only more accurate but also more equitable, bridging gaps between advanced research centres and standard clinical settings. This study represents a step towards that goal, offering both scientific clarity and practical value.