Second, to evaluate the roles of AURA, CDK9, and MOK in chordoma cell proliferation, we silenced AURA, CDK9, and MOK protein expression in chordoma cell lines using siRNAs, and demonstrated that knockdown efficacy to be over 70% in JHC7 cells (Figures 5A, –F). The gene discussed is CDK9; the disease is chordoma.