As shown here, overexpressing WT H2AX but not monoubiquitination-deficient K119/120R H2AX protected HCC cells from IR in response to DNA damage, compared to that in control cells, which indicated that H2AX monoubiquitination plays an essential role in facilitating DNA damage signal passage and inducing radioresistance in HCC cells. The gene discussed is H2AX; the disease is hepatocellular carcinoma.