CYP4Z1 and breast cancer: Two recent studies showed that six2 promotes the stemness of breast cancer cells via different mechanisms; one indicated that six2 activates the competing endogenous RNA network between CYP4Z1 and pseudogene CYP4Z2P via directly binding to their promoters 17, and another work demonstrated that Six2 directly binds to the sox2 SRR2 enhancer region 18.