ERRα’s expression correlated with high Her2/ErbB2, a tyrosine kinase receptor amplified in 15% to 25% of breast cancers that also confers aggressiveness [77] and that increases ERRα’s transcriptional activity via phosphorylation through MEK/MAPK and PI3K/Akt [79,80] (Figure 1). This evidence concerns the gene ERBB2 and breast cancer.