SPP1 and neuroblastoma: ,35 They are known to secrete TGF-b1,36 which directly targets cytotoxic T cells and participates in the differentiation of regulatory T cells.37, 38, 39 Our research also highlighted the enrichment of SPP1+ TAMs in NB-BBM, which closely interacted with the metastatic subpopulation of NB bone marrow (NB3) and potentially contributed to NB progression to BBM through oxidative phosphorylation and aberrant TGF-b1 expression.