Murine studies conducted in our laboratory have also established that bortezomib treatment sensitizes tumors in vivo to killing by adoptively infused syngeneic NK cells; murine renal cell carcinoma line (RENCA) tumors in BALB/c mice grew significantly slower and survival was prolonged when syngeneic NK cell infusions were given following bortezomib treatment compared to mice receiving NK cell infusions alone or bortezomib alone. This anti-tumor effect was further potentiated by eradicating T-regulatory cells prior to adoptive NK cell infusion and by administering interleukin-2 after adoptive NK cell infusion.