Figure 6. Therapeutic effect of the combination of radiation and a HIF-1 inhibitor.

(a) The tumour bearing mice were irradiated with γ-rays (25 Gy) and treated with or without YC-1 1 min after the irradiation to suppress the activation of HIF-1. Kaplan–Meier analysis of recurrence-free periods after irradiation alone (blue) or after the combination of radiation and a HIF-1 inhibitor (red). n=15. (b) During the experiment of (a), relative tumour volume was calculated as the ratio of the tumour volume on each day to the corresponding volume on day 0. Blue triangle: radiation alone group. Red square: radiation & YC-1 group. Mean±s.d. n=15. *P<0.05 (Student's t-test).