We have previously shown that treatment of prostate cancer cells with heregulin induces downstream activation of Ack1 kinase and AR phosphorylation at Tyr-267 while treatment with epidermal growth factor, interleukin-6 and bombesin (gastrin-releasing peptide) induces Src kinase activation and AR phosphorylation at Tyr-5349. Here, AR is linked to prostate cancer.