FUS is a member of the FET protein family and is reported to be a regulator of circRNA biogenesis; CircROBO1 upregulates KLF5 by sponging miR-217-5p, enabling KLF5 to activate FUS transcription and promote circROBO1 back-splicing, forming a positive feedback loop to enhance BC-derived liver metastasis [46]. Here, KLF5 is linked to breast cancer.