Thus, the viability assessment of human glioblastoma spheroids after exposure to modified NK cell lines demonstrated enhanced cytotoxicity of YT-Vav1+CISH–/– and YT–Vav1+B2M–/– cells compared with standard unmodified YTwt line, this being consistent with earlier experiments on a human glioblastoma monolayer culture of [10]. Here, B2M is linked to glioblastoma.