SPP1 and adenocarcinoma: Spatial analysis using immunofluorescent staining indicated a close spatial relationship between IGFBP2+ fibroblasts and SPP1+ macrophages in lung cancer tissues, with a significant correlation observed between SPP1 and IGFBP2 expressions in LUSC (Fig. 1G), suggesting their involvement in the transition between adenocarcinoma and squamous cell carcinoma (Fig. S3E).