Dual‐labelling indicated that ∆Np63/p40+ cells were not positive for smooth muscle actin (SMA), a reliable marker of cancer‐associated myoepithelial cells 25, and were EMA− (a luminal epithelial differentiation marker) and ER−/weak in ER+ cancers (Figure 1B–D). The gene discussed is MUC1; the disease is cancer.