Study published in Cancer Research also showed that Stat5 keeps androgen receptors transcriptionally active.
Scientists at Jefferson’s Kimmel Cancer Center found that a signaling protein, Stat5, that is key to prostate cancer cell growth is turned on in nearly all recurrent prostate cancers that are resistant to hormone therapy.
In previous work, the researchers showed that when Stat5 is turned on in primary prostate cancer, men are more likely to have recurrent disease.
In the current study, the team examined human prostate cancer cells of 198 patients with prostate cancer recurrence. They found that Stat5 was active in 74% of all recurrent prostate cancers. Of these patients, 127 had been treated with androgen deprivation therapy. The researchers found Stat5 was active in 95% of these hormone-resistant tumors.
The investigators also showed that Stat5 interacts with the androgen receptors, which keeps them transcriptionally active, and this synergy between Stat5 and hormone receptors in recurrent prostate cancer cells helps Stat5 maintain its activity.
The findings are reported in the January 1, 2008, issue of Cancer Research.