IL15 and glioblastoma: First, the cytotoxic activity of NKAR-NK-92 and NKAR_RD-IL15-NK-92 cells against homogeneous cultures of GL261/EGFR, GL261/ErbB2, and GL261/ErbB2/EGFR glioblastoma cells in the presence of NKAB-EGFR or NKAB-ErbB2, or a combination of both molecules, was tested.