To investigate the role of TREM2 in GBM radioresistance, U87MG-R and GL261-R cell lines were firstly established according to the schematic illustration shown in Fig. S1 A. The result of colony formation assay showed that the plating efficiencies of U87MG-R and GL261-R cells were significantly increased compared with U87MG and GL261 cells; moreover, the survival curves of U87MG-R and GL261-R cells descended more slowly than those of U87MG and GL261 cells (Fig. S1 B, C). The gene discussed is TREM2; the disease is glioblastoma.