CHEK1 and breast carcinoma: Downregulating CBX8 can upregulate the expression of P21, CHK1, and WEE1, thereby inhibiting cyclin-dependent kinases, prolonging the cell cycle, and reducing cell proliferation.[20] Chung et al demonstrated that CBX8 is the main regulator of breast cancer in vivo and in vitro, and its expression is upregulated in breast cancer tissues, which indicates poor prognosis of patients with breast cancer.