SCAI and breast cancer: Multidrug resistance is a huge obstacle for the HCC treatment.22 The role of circRNA in the cancer‐related multidrug resistance is still unclear.23, 24 For example, circRNA Cdr1as overexpression inhibits the ovarian cancer cell proliferation and promoted the cisplatin‐induced cell apoptosis by regulating the miR‐1270/SCAI signalling pathway.25 CircKDM4C is down‐regulated in breast cancer tissues and associated with poor prognosis and metastasis.