POU5F1 and cancer: First, we showed that CRISPR/Ca9-mediated knockout of WAVE3 in MDA-MB-231 cells (W3-CRISPR-1 and -2, Figure 2A) and WAVE3-shRNA-knockdown in BT549 cells (sh-W3-1 and -2, Figure 2E) significantly inhibited the expression levels of Oct4 (90% loss for 231, Figure 2B; and 80% loss for BT549, Figure 2F), Nanog (60% loss for 231, Figure 2C; and 50% loss for BT549, Figure 2G), and Sox2 (∼50% loss in 231, Figure 2D; and 40% loss in BT549, Figure 2H), well-established markers of cancer stem cells.