PU.1 induces growth arrest and apoptosis in both L428^tetPU.1 and KM-H2^tetPU.1 cHL cell lines in vivo. Tumor size in L428^tetPU.1 (A) and KM-H2^tetPU.1 (B) xenograft mouse models over the course of 7 days. Tumors in L428^tetPU.1 and KM-H2^tetPU.1 mice given tetracycline continued to grow (●), compared with tumors in mice without tetracycline, which ceased to grow and in some cases decreased in size (○). Tumors in L428^tetPU.1 (C) and KM-H2^tetPU.1 (D) xenografts did not grow after tetracycline withdrawal. Left panels: Tumors in a xenograft mouse taking tetracycline water. Right panel: Tumors after tetracycline withdrawal. Survival curves of L428^tetPU.1 (E) and KM-H2^tetPU.1 (F) xenograft mice. L428^tetPU.1 xenograft mice taking tetracycline all died within 96 days, whereas 7 of 8 mice without tetracycline survived > 190 days. KM-H2^tetPU.1 xenograft mice taking tetracycline all died within 143 days, whereas 6 of 8 mice without tetracycline survived > 155 days.