SPP1 and neoplasm: In various solid tumor tissues, functional enrichment analysis and gene expression profiling in scRNA-seq data delineate distinct roles for different tumor-associated macrophages (TAMs): FCN1 + TAMs show a proinflammatory influence, SPP1 + TAMs are implicated in metastasis, angiogenesis, and cancer stem cell activation, C1Q + TAMs play a role in immune regulation and suppression, and CCL18 + cells represent terminal immunosuppressive macrophages with potent immunosuppressive abilities and the capacity to promote tumor metastasis[20].