Researchers at Jefferson's Kimmel Cancer Center in Philadelphia have identified the protein that remains active in almost all recurrent prostate cancers, which are resistant to hormone therapy.
Dr. Marja Nevalainen, associate professor of Cancer Biology, has revealed that the protein identified by her team is Stat5, which is key to prostate cancer cell growth.
She believes that this protein might be a specific drug target against an extremely difficult-to-treat cancer.
The researcher further said that her team had also found that the convergence of two biological pathways could be responsible for making such hormone-resistant prostate cancers especially dangerous.
According to her, a synergy between Stat5 and hormone receptors in recurrent prostate cancer cells helps each maintain its activity.
"These findings validate Stat5 as a potential drug target in prostate cancer, and in particular, in a form of prostate cancer for which there are no effective therapies," Dr. Nevalainen says.
For the study, the researchers examined human prostate cancer cells of 198 patients with prostate cancer recurrence.
They found that Stat5 was active in 74 percent of all recurrent prostate cancers. Among such patients, 127 had been treated with androgen deprivation therapy.
The team found that Stat5 was active in 95 percent of these hormone resistant tumours, suggesting that it was more likely to be active if the patient had been treated with hormone deprivation therapy.
Researchers showed that Stat5 interacts with the androgen receptors, and keeps them 'transcriptionally active.'
The findings have been published in the journal Cancer Research.