A previous study demonstrated that LCN2 derived from granulocytes activates astrocytes, triggering the recruitment of myeloid cells to the brain.17 Our scRNA-seq data revealed that BM with high LCN2 expression presented an increased proportion of infiltrating macrophages, whereas no such difference was observed in primary tumor tissues (Fig. 4c). The gene discussed is LCN2; the disease is neoplasm.