PTEN and neoplasm: It has been shown that ER-stressed HCC cells deliver miR-23a-3p in exosomes to macrophages, which activates the PI3K-AKT pathway by inhibiting phosphatase and tensin homolog (PTEN) to increase PD-L1 expression, reducing the CD8 + T cell ratio and IL-2 production, thereby resulting in tumor escape [90].