The experimental observations indicated that the mutant strain lacking both LAT and RL1 genes exhibited significantly reduced proliferation in the HS683 glial tumor cell line and the SH-SY5Y neuroblastoma cell line, and the size of the plaques in Vero cells also proved that its virulence was reduced compared with that of the wild-type and LAT-HSV-2 strains. The gene discussed is LAT; the disease is glioma.