NCOA1 and breast cancer: To determine whether Ncoa1 expressed in the mammary tumor cells supports angiogenesis, we performed in-gel-angiogenesis assay in mice to assess the angiogenesis-inducing capabilities of two Ncoa1 WT (W1 and W2) and two Ncoa1 knockout (K1 and K2) tumor cell lines, which were previously established from Tg(MMTV-PyMT) and Ncoa1−/− × Tg(MMTV-PyMT) mouse mammary tumors [13, 21].