ERBB2 and breast cancer: Finally, to confirm the anti-metastatic effect of EZH2 inhibition in distinct molecular subtypes of human breast cancer in vivo, we orthotopically transplanted patient-derived xenografts (PDX) established from Luminal B (HCI003, GCRC 1986)30 or HER2+ (GCRC1991, GCRC 2080) samples into the mammary fat pads of immune compromised hosts and treated mice with either GSK-126 or vehicle for 5 weeks.