STING1 and glioblastoma: In line with the effects of hDT806 in HNSCC xenograft models, indeed, an IHC experiment of the dissected GL261vIII tumors revealed a dramatic increase in STING-positive cells in hDT806-treated tumors compared to the vehicle-treated tumors, from 1.1 ± 0.4 to 9.9 ± 0.5% (n = 4, p < 0.001; Supplementary Fig. S3), indicating that STING upregulation occurs in response to hDT806 in both glioblastoma and HNSCC.