P21-activated kinase 5 potentiates the chemoresistant phenotype of liver cancer

Dear Editor, Systemic chemotherapy is hindered for the treatment of advanced HCC,largely due to the multidrug-resistance pheno-type.1 One of the major mechanisms of drug resistance,increased drug efflux,is mediated by various membrane transporters.ABCB1(MDR1)is one of the most extensively studied members of the ATP-binding cassette family and has been shown to be elevated in multiple tumor types.2 However,most clinical trials with ABCB1 inhibitors failed to reach the desired endpoints,which calls for an in-depth understanding of ABCB1 gene regulation.