STAT3 and cancer: Accumulating evidences indicated the pro-inflammatory, IL-6 in tumor microenvironment has a trait to activate IL-6/STAT3 signal pathway, and promote the development of cancer, include HCC and the aggressiveness of HCC cells (14–16), IL-6 is highly expressed in liver cancer tissue and loaded in serum, and overexpressed IL-6 is closely associated with the staging, severity, and prognosis of HCC (17).