Detection and Characterisation of Fibronectin Structures in the Tumour Extracellular Matrix*

Characterising the tumour extracellular matrix (ECM) holds promise for identifying predictive biomarkers, particularly in assessing patient response to immunotherapy. While the cellular components of the tumour microenvironment have been extensively characterised, the non-cellular elements of this ecosystem remain underexplored. In this study, we investigated the geometry of Fibronectin (FN) in immunofluorescence images, a key ECM protein, in head and neck tumours. Our analysis identified two primary classes associated with FN structure: (a) aligned fibres, and (b) reticular fibre-like, which exist on a spectrum of structural variation. We proposed an approach leveraging Voronoi diagrams as adaptive windows. Circular statistics were then used to capture the spatial organisation of FN, providing insights into its structural heterogeneity within the tumour microenvironment.