DANCR essentially regulated EMT and cancer stemness of malignant breast cancer cells. (A,B) Western blot on EMT‐related biomarkers SNAIL1, SLUG, MMP‐2, MMP‐9, E‐cadherin, and Vimentin showed that shDANCR inhibited EMT in MDA‐MB‐231 and MDA‐MB‐468 cells. Representative western images are shown on the left and the quantification on the right. (C,D) Mammosphere assay showed that shDANCR significantly inhibited mammosphere formation. Representative images of mammosphere formed in each group are shown in (C) and the quantification on the number of mammospheres in (D). (E–H) qRT‐PCR (E,F) and western blot (G,H) show shDANCR inhibited the expression of stemness‐related biomarkers CD44, CD133, OCT3/4, and NANOG, on mRNA and protein level in indicated breast cancer cells. n = 3, data are shown as mean ± SD. Student’s t‐test was used to determine statistical significance: *P < 0.05, **P < 0.01.