NUMB and breast cancer: These data are consistent with the known role of NUMB LOF in the emergence and expansion of the CSC population and in BC tumorigenesis.[1a,e,h,m,r] The role of the CRL7FBXW8 complex in NUMB‐deficient BC was specifically due to its ability to degrade NUMB, since the effects of its silencing were reversed by the simultaneous ablation of NUMB.