To advance understanding of FGF23+ PMT pathogenesis, this study, to our knowledge, provides the first analysis of the tumour-associated MC population, with a specific focus on spatial phenotyping of MC integration into the immune and stromal landscapes of the tumour microenvironment in situ, as well as on intercellular interactions and the secretory pathways of specific proteases shaping the functional architecture of the tumour microenvironment. Here, FGF23 is linked to neoplasm.