HIF1A and colorectal cancer: In colorectal cancer (HCT116) cells subjected to 0.5% oxygen then reoxygenated for 10 min prior to irradiation, it was found that HIF‐1 may actually act as a radiosensitiser through coordinating apoptosis and proliferation rates, but also that the impact of HIF‐1 inhibition on radiosensitivity is likely to be dependent on the physiological microenvironment.27