Importantly, relative to mice transplanted without leukemia, TetH60+ cells from mice transplanted with BC-CML had more characteristics of exhaustion–increased inhibitory molecule expression, increased Blimp-1 and Eomes and reduced IFN-γ production–indicating that rather than being stimulatory, BC-CML cells augment exhaustion (Fig. 5a–d). This evidence concerns the gene PRDM1 and breast cancer.