KLF4 and neoplasm: CircPLEKHM3 was found to function as a tumor suppressor in OC by sponging miR-9 to regulate the endogenous expression of breast cancer 1 (BRCA1), DNA heat shock protein family (Hsp40) member B6 (DNAJB6) and kruppel like factor 4 (KLF4) which consequently inactivates oncogenic AKT1 signaling (Zhang L. et al., 2019).