Men on androgen deprivation therapy (ADT) for prostate cancer may face an unexpected wrinkle: a new source of testosterone. Where is it coming from? Bacteria! But how can this be?

It turns out, Sfanos says, that “the bacteria that live in areas of the human body, such as the gut, are capable of converting substances found in the gut into hormones, including androgens (male hormones). These bacterial androgens can then interfere with ADT.”

In a recent study of men with advanced prostate cancer, Sfanos teamed up with colleagues from the University of Illinois Urbana-Champaign. Her role was to look for bacterial androgen-producing genes in the gut and urinary tract and to determine the prevalence of these genes in relation to treatment response to the prostate cancer drug abiraterone acetate (Zytiga®).

Her colleagues identified two new bacterial genes that are capable of converting androgen precursors into androgens such as testosterone. “These bacterial genes were present in fecal samples and were elevated in a subset of men who were not responding to treatment. We also found that in addition to the gut, bacteria that produce androgens are also present in the urinary tract!”

The significance of androgen-producing bacteria in the urinary tract is not yet clear, Sfanos says. “However, it is possible that these bacteria may contribute to the early development of the disease. Overall, the study moves us one step closer to identifying bacterial genes that require targeted therapies, so that prostate cancer drugs can be more effective.”