The specificity of SPP1 as a marker for SPP1+ macrophages in CRC was further confirmed by immunohistochemistry staining from The Human Protein Atlas (THPA) database,77 which showed specific expression of SPP1 protein in CRC samples but not in NC, NL, and HCC samples (Fig. 4E). This evidence concerns the gene SPP1 and hepatocellular carcinoma.