IL15 and glioblastoma: Cytokines have also been studied in combination with CAR T. A preclinical study of GD2-CARs modified to contain a constitutively active IL-7 receptor was associated with durable tumor elimination in murine GBM xenografts [225], and another preclinical study showed that GD2-CARs with transgenic IL-15 expression achieved a 50% complete response rate in an intracranial xenograft GBM model [226].