TOPBP1 and breast neoplasm: We reported that CK2-catalyzed HTATSF1 pS748 is critically involved in breast tumorigenesis, which raises the possibility of combining chemotherapeutic drugs targeting HTATSF1 pS748 or the HTATSF1–TOPBP1 binding surface for the treatment of HTATSF1–TOPBP1 proficient breast tumors.