Pin1 controls CSC self-renewal, replicative potential and frequency by antagonizing the negative effect of Fbxw7α E3 ubiquitin-ligase on the Notch receptor pathway, a fundamental regulator of cell fate frequently subverted in breast cancer (Han et al, 2011; Ranganathan et al, 2011; Reedijk, 2012). This evidence concerns the gene PIN1 and breast cancer.