MiR-21-5p in hepatocellular carcinoma cell (HCC)-derived exosomes promotes the polarization of TAM towards M2 phenotype by regulating the SP1/XBP1 signaling pathway, which leads to immunosuppressive state in the TME, enabling tumor cells to escape the attack of the immune system, and thus promoting the development and deterioration of HCC [131]. This evidence concerns the gene XBP1 and hepatocellular carcinoma.