Researchers have discovered that the protein Siah2 keeps a portion of androgen receptors constantly active, allowing prostate cancer cells to resist treatment. Based on this new information, Siah2 could make a promising biomarker for tracking a prostate cancer patient’s response to therapy. Inhibiting Siah2’s interaction with the androgen receptor complex might also provide a new method for re-sensitizing castration-resistant prostate tumors to hormone therapy.