Inhibition of PPARγ transcriptional activity using the antagonist GW9662 resulted in increased cell death, specifically of the ERBB2-positive BT474 and MDA-MB-361 breast cancer cells, in a time-dependent and dosage-dependent manner, but not of the ERBB2-negative MCF-7 or normal HMECs (Figure 1a). This evidence concerns the gene ERBB2 and breast cancer.