CircKIF4 is involved in glucose metabolic reprogramming of BC, and silencing of circKIF4A dramatically affects glucose uptake and lactic acid production of BC cells, and it affects the metabolic reprogramming of BC mainly through the circKIF4A–miR-335–OCT4/ALDOA–HK2/PKM2 axis [51]. The gene discussed is POU5F1; the disease is breast cancer.