To understand how MTA1 promotes NPC cell proliferation and colony formation, we examined cell cycle progression of C666-1 cells depleted of MTA1. Compared with control cells, C666-1/MTA1-si cells displayed an increased percentage of cells in G1 phase and fewer cells in G2 phase (p < 0.001), but no significant difference in S phrase distribution (Figure 1C). This evidence concerns the gene MTA1 and nasopharyngeal carcinoma.