While many breast cancers can be treated by reducing levels of the female hormone estrogen, some breast cancers may also respond to a reduction in the male hormone, androgen, according to a study published last week (June 24) in The EMBO Journal.
Cancers that express the estrogen receptor (ER), require the hormone for growth, which is why drugs that deplete its availability in the body have proven an effective treatment for the 30 percent of breast cancers expressing this receptor. But there is another subset of breast cancers that are untreatable with estrogen-blocking drugs because they only express the androgen receptor, and no ER. To find out how the androgen receptor affected the growth of these breast cancers, the authors examined tumors only expressing the androgen receptor and showed that it activated a similar genetic program as the estrogen receptor, resulting in tumor growth. The finding suggests that existing androgen-receptor-blocking drugs could help treat the 8-12 percent of breast cancer patients with this specific subtype, called molecular apocrine cancer.
For other examples of existing drugs with new applications, read our biobusiness story Teaching an Old Drug New Tricks in The Scientist's April Issue.
(Hat tip to Fierce Biotech Research.)