In summary, ZXF1 regulates P21 expression in endometrial cancer through two mechanisms: by regulating P21 protein expression through the miR‐378a‐3p/PCDHA3 axis and by directly binding to P21 to prevent its CDC20‐mediated ubiquitin degradation (Fig. 7). The gene discussed is CDKN1A; the disease is endometrial cancer.