PCNA and hepatocellular carcinoma: In addition to EMT‐mediated metastasis and invasion, cancer cells have weak proliferation ability in medium containing the released cytokines, and low levels of PCNA expression and p‐AKT are observed, indicating that Pi starvation‐mediated macrophage‐conditioned medium promotes the apoptosis of HCC cells due to the activation of PI3K/AKT signal transduction.40