Hypoxia-circular RNA crosstalk to promote breast cancer.

The expression of hypoxia-inducible factors (HIFs), particularly HIF-1, plays a major role in the adaptation of solid tumors to hypoxic conditions. The activation of the HIF pathway results in an expression of genes involved in the promotion of cell growth, proliferation, vascularization, metastasis, and therapeutic resistance. Circular RNA (CircRNA) is considered as a major regulator of gene expression.