Moreover, KRT19-regulated Notch signaling in a NUMB transcription-dependent manner was mediated by β-catenin/RAC1 nuclear import [13], although KRT19 regulates Wnt signaling in both cancers without influencing NUMB transcription in a colon cancer model (Figure 4a), suggesting a differential mechanism might be involved in the two cancers. Here, RAC1 is linked to cancer.