POSTN and neoplasm: In iCCA specifically, spatial mapping of the “leading-edge” tumour region (bordering non-tumour tissue) by single-cell + ST found that tumour cells enriched in the edge area were tightly associated with stroma (POSTN+/FAP+ fibroblasts) and endothelial cells, while CD8+ T cells in these same zones exhibited an exhausted phenotype with low cytotoxicity, likely reflecting hostile metabolic/immune micro-niches (125).