Deciphering the divergent roles of progestogens in breast cancer

Most breast cancers are driven by oestrogen receptor‑α. Anti-oestrogenic drugs are the standard treatment for these breast cancers; however, treatment resistance is common, necessitating new therapeutic strategies. Recent preclinical and historical clinical studies support the use of progestogens to activate the progesterone receptor (PR) in breast cancers. However, widespread controversy exists regarding the role of progestogens in this disease, hindering the clinical implementation of PR‑targeted therapies. Herein, we present and discuss data at the root of this controversy and clarify the confusion and misinterpretations that have consequently arisen. We then present our view on how progestogens may be safely and effectively used in treating breast cancer.Jason S. Carroll, Theresa E. Hickey, Gerard A. Tarulli, Michael Williams and Wayne D. Tille