Male sex hormones (androgens) regulate tumour growth in prostate cancer. The only effective treatment for advanced prostate cancer is the removal of androgens using medication, or the surgical removal of the testes — treatments that cause impotence and a decreased sex drive. The results are usually temporary since some tumour cells survive, become independent of androgens, and continue to grow. Prostate cancer cells depend primarily on the androgen receptor, which encodes genetic information, for growth and survival. Gang Wang is studying how the androgen receptor decreases the expression of the SESN1 gene — a gene that may inhibit the growth of prostate tumour cells. Wang believes the SESN1 gene is no longer repressed when patients receive hormone therapy. This would explain the initial suppression of prostate cancer cells seen in these patients and the subsequent reappearance of cancer cells which later follows. Wang will confirm if the androgen receptor begins lowering the gene following therapy, allowing the cancer cells to grow. If so, the SESN1 gene could be a promising therapeutic target for treating prostate cancer.