The nanoparticles prolonged the formation of phosphorylated histone H2AX (γ‐H2AX), which is a marker of DSB breaks, increased the exposure of radiation‐induced DNA damage; and thus, had the potential to synergistically improve radiotherapy in prostate and colorectal cancers.[105] In addition, reactive oxygen species (ROS) produced by radiotherapy can induce DNA damage for tumor killing; therefore, tumor hypoxia may lead to insensitivity to radiotherapy. Here, H2AX is linked to colorectal cancer.