Based on the report that β-arr1 interacts with HIF-1α in breast cancer cells [31], Zecchini et al., have carried out the genome wide-map of β-arr1 transcriptome in prostate cancer cells reporting binding sites for β-arr1, p300 and HIF-1α on the regulatory regions of target gene promoter in these cancer cells under hypoxic or pseudohypoxic conditions [32]. This evidence concerns the gene EP300 and breast cancer.