Spatial transcriptomics uncovers TAC-OGEs heterogeneity and FN1/MMP9 signature in ameloblastoma

<h4>Objective</h4>This study aims to explore how the tumour microenvironment influences the aggressiveness, malignancy, and recurrence of ameloblastoma. By employing a spatial omics approach, we will examine the characteristics of the invasive front of ameloblastoma.<h4>Methods</h4>We systematically characterised the cellular heterogeneity of ameloblastoma using spatial transcriptomic sequencing combined with integrated omics analysis of clinical tumour specimens. Additionally, we independently validated the spatial expression patterns and levels of FN1 and MMP9 in ameloblastoma through immunohistochemistry in an independent case series of 15 specimens, further supported by single-cell resolution multiplex immunofluorescence.<h4>Results</h4>Spatial transcriptomic sequencing delineated the ameloblastoma tumour ecosystem into seven primary cell clusters: epithelial tumour cells, fibroblasts, myeloid cells, endothelial cells, T cells, B cells, and Tumour-associated cells with osteoclast-like gene expression (TAC-OGEs). Significantly, cell clusters located at the tumour's invasive front demonstrated notably increased expression of FN1 and MMP9. A more detailed analysis within the TAC-OGE compartment identified seven phenotypically distinct subclusters. Interestingly, their differentiation states formed a spatial gradient, extending from the tumour core to the periphery. This spatial expression pattern of FN1 and MMP9 was confirmed through immunohistochemical staining at the tumour-stroma interface.<h4>Conclusion</h4>Our findings collectively reveal the cellular heterogeneity of ameloblastoma and highlight tumour-margin-associated TAC-OGEs as potential spatially associated components of local invasion. These results suggest that targeting TAC-OGE-associated processes may represent a potential therapeutic strategy in the management of ameloblastoma.