In addition, it was speculated that circVRK1 was negatively correlated with stemness of BCSCs through the miR-153-5p/KLF5 axis, as miR-153-5p was one of the predicted miRNA targets of circVRK1 and was previously demonstrated to be involved in stemness maintenance of BC via reducing the expression of KLF5 [148]. This evidence concerns the gene KLF5 and breast cancer.