SPP1 and hepatocellular carcinoma: We found that the expression of all four genes was positively correlated with the infiltration abundance of tumor immune cells, except for GADD45A, which was negatively correlated with the infiltration abundance of tumor immune cells, and the expression levels of LY6E, IFITM1, and MT1M were all down-regulated in HCC, suggesting that the down-regulation of LY6E, IFITM1, and MT1M may negatively regulate tumor immune response in HCC, only GADD45A, and SPP1 may be associated with promoting tumor immune responses in HCC.