GZMB and neoplasm: XBP1s interacts with T-BET to bind to the proximal region of the promoter of the granzyme B (Gzmb) gene, which increases the transcription of Gzmb. Therefore, the knockdown of XBP1s reduces the percentage of CD107a+ NK cells showing cytotoxicity against tumor cells and inhibits the IL-15-induced survival of NK cells.