Therefore, to study the effect of BRCC3 knockdown on the induction and repair of DSBs in NPC cells, Cells were transfected with BRCC3 or control siRNAs 24 h prior to irradiation (2 Gy), and we conducted immunofluorescence before and 0.5 h, 6 h, 12 h, 24 h after irradiaton to examine the phosphorylation of H2A.X at Ser139 (γH2AX) DNA repair foci in response to ionizing radiation. Here, H2AX is linked to nasopharyngeal carcinoma.