Several circRNAs have been identified to regulate the expression of HIFs, especially for HIF-1α, thus contributing to cancer progression, invasion, metabolism reprogramming, immune escape, et al. For instance, circRNA_100859 absorbs miR-217 to release the inhibition of HIF-1α expression, facilitating colon cancer progression [37]. The gene discussed is HIF1A; the disease is malignant colon neoplasm.