CDK9 and neoplasm: Expression of CDK9 in HepG2, MHCC-97H, HLE, Huh7, and Hep3B cells was significantly higher than that in tumor cells HLE and normal cells LO2, and the CDK9 inhibitors LDC067 and PHA767491 inhibited the proliferation of HepG2 in vitro and in vivo, respectively.