Consistent with the findings of the BC patient cohort (Fig 3B), immunofluorescent staining confirmed that p‐TFCP2L1 and CDK1 expression was upregulated in xenograft tumors derived from empty construct‐, wild type‐, and T177E TFCP2L1‐expressing T24 cells (Fig 7E and Appendix Fig S7A), while it was repressed in T177A TFCP2L1 and shTFCP2L1 xenografts. This evidence concerns the gene CDK1 and breast cancer.