Moreover, it is controlled by the overgeneration of VEGF and hypoxia induced factor (HIF-1α) in tumor cells [130], resulting in decreased sensitivity of cancers to radiotherapy (RT), causing chemoresistance and also greatly affecting the efficacy of O2-related treatments, such as photodynamic therapy (PDT) and sonodynamic therapy (SDT) [131]. The gene discussed is HIF1A; the disease is cancer.