Dissecting the transcriptomic profile of CD163+ macrophages in hepatocellular carcinoma with VETC+ angiogenesis provides potential targets of treatment

Introduction: Hepatocellular carcinoma (HCC) is characterized by a highly vascularized tumor microenvironment (TME), with VETC being a distinctive, frequent, and prognostically unfavorable type of this vascular TME. VETC+ HCCs show lymphocyte deprivation and enrichment with large, foamy macrophages distributed close to endothelial cells. Methods: A total of 7 resected HCCs were retrospectively analyzed according to VETC status. Spatial transcriptomic profiling was performed on formalin-fixed, paraffin-embedded samples using NanoString GeoMx™ DSP, followed by differential expression and pathway analyses. SPP1 expression was further evaluated by immunohistochemistry and multiplex immunofluorescence. Results: This study aimed to characterize these macrophages with a spatial transcriptomic approach. We demonstrated that they exhibit a pro-tumor, M2-like tumor-associated macrophages (TAMs) signature (SPP1, ACP5, GPNMB, and FABP5), distinct from those in VETC- cases. They are enriched with specific pathways involved in immunosuppression and angiogenesis. SPP1, ADAM9, and MMP9 were among the genes mostly upregulated. Immunohistochemistry analysis confirmed strong SPP1 expression in TAMs spatially associated with endothelial cells in VETC+ cases. Conclusion: Our findings suggest that M2-like TAMs in VETC+ HCCs contribute to both angiogenesis and immunosuppression. SPP1 and ADAM9 could represent novel therapeutic strategies to reshape TAMs and suppress VETC onset.