ONECUT2 and breast cancer: OC2 protein is expressed in the luminal B BT-474 cell line, in the metastatic triple-negative MDA-MB-231 BC cells, in weakly metastatic luminal A MCF-7 BC cells and at detectable but substantially lower levels in luminal A T-47D and nontumorigenic 184B5 cells (Supplementary Fig. 3A, B).