For example, circFBXL5 can promote 5-FU resistance of BC by inducing MDA-MB-231 and MDA-MB-453 cell invasion and apoptosis, and the miR-216b/HMGA2 axis is involved in this process, suggesting that circFBXL5 can sponge miR-216b to promote HMGA2 expression (Zhu et al. 2021). Here, HMGA2 is linked to breast cancer.