CD8A and neoplasm: In two murine models, Markovsky et al. suggested that partial tumor volume irradiation (10 Gy, 15 Gy or 20 Gy delivered to 50% of the tumor using a 2 x 2 cm collimator) led to tumor responses similar to full tumor volume irradiation (10 Gy, 15 Gy or 20 Gy delivered to 100% of the tumor) via an immunostimulatory mechanism involving an increase in CD8+ T-cell traffic throughout the non-irradiated portion mediated by an increase in ICAM (60).