KLRK1 and glioblastoma: Moreover, the overexpression of natural killer group 2 member D ligands (NKG2DLs), such as the major histocompatibility complex class I chain-related gene A/B (MICA/B) and UL16 binding protein (ULBP), has been reported in GBM stem cells (GSCs), and CAR-T expressing natural killer group 2 member D (NKG2D) has been shown to exhibit effective tumor-elimination effect on GBM models, with insignificant treatment-related toxicity [21].