PI3Kγδ Inhibitor plus Radiation Enhances the Antitumor Immune Effect of PD-1 Blockade in Syngenic Murine Breast Cancer and Humanized Patient-Derived Xenograft Model

Murine breast cancer cells were grown in both immune-competent and -deficient BALB/c mice, and tumors were irradiated by three fractions of 24 Gy. A PD-1 blockade and a phosphoinositide 3-kinase (PI3K)γδ inhibitor were then administered every other day for two weeks.