BCL9 and breast cancer: Subsequently, BCL9 protein expression by Western blot was investigated in five breast cancer cell lines including: MCF7 (ER+ PR+), T47D (ER+ PR+), CCH1 (DCIS Basal), DCIS.COM (DCIS Basal), SUM225 (DCIS HER2 + ) as well as MCF10A (immortalized, non-tumorigenic mammary epithelial cell line), and 293 T (kidney embryonic cell line).