HIF1A and cancer: Hypoxia, an important hallmark of tumor microenvironment (TME) for solid tumors, is caused by cancer cell fast proliferation and blood vessel abnormality during tumor angiogenesis.[1] Mounting studies have confirmed that tumor hypoxia is responsible for resistance of numerous therapeutic treatments, including chemotherapy,[2] radiotherapy,[3] and photodynamic therapy.[4] Additionally, reports show that hypoxia and hypoxia‐inducible factors (e.g., HIF‐1 and HIF‐2) expression are tightly associated with increased population of cancer stem cells (CSCs).