SERPINE1 and hepatocellular carcinoma: Cancer‐associated fibroblast (CAF), one of the major stromal cells in the HCC tumor microenvironment, encourages the polarization of TAMs into M2 phenotype in vitro simulation experiments while producing CXCL12 to stimulate M2 to secrete plasminogen activator inhibitor‐1 (PAI‐1), which mediates EMT to strengthen the malignant behavior of HCC cells.33