To explore the biological function of CBX7 in glioma cells, EdU, CCK8, wound-healing and transwell assays were performed to study the influence of CBX7 on cell proliferation, migration and invasion. After incubation with si-CBX7 for 48 h, the growth rate of U251 cells was increased. Conversely, the two stable CBX7 expressing cell lines, U87 and LN229, showed impairment in proliferation capability (Figure 3B and 3C). A known malignant behavior of glioma cells is its strong tendency for local invasion. We found that si-CBX7 treatment potentiated tumor aggressiveness in U251 cells compared with si-ctrl treatment. Conversely, the migrative and invasive capability in CBX7-overexpressing cell lines was suppressed (Figure 3D and 3E). In order to eliminate the influence of differences among cell types, we performed part of experiments in U251 with the use of siRNA and lentiviral vector and the results were consistent with the previous studies (Supplementary Figure 2C–2F). These findings imply that CBX7 is a potential tumor suppressor gene in glioma cells.