We also assessed the impact of EC reprogramming on autochthonous mammary tumors in the MMTV-PyMT, Cdh5CreERT2, LSL-COUP-TFII GEMM: we induced ectopic COUP-TFII expression in 3-month-old mice, at an age when mice were beginning to develop tumors but before tumors became palpable. The gene discussed is NR2F2; the disease is breast cancer.