This finding is consistent with Zhou et al.’s research, which employed single-cell RNA analysis across different phases of osteosarcoma progression, identifying critical gene expression patterns in tumor cells and the surrounding microenvironment, with particular emphasis on variations in immune cells, and detected substantial infiltration of pro-inflammatory FABP4+ macrophages in lung metastatic osteosarcoma (Zhou et al., 2020a). The gene discussed is FABP4; the disease is osteosarcoma.