NEW ORLEANS — Most women and men with hormone receptor-positive breast or prostate cancers eventually become resistant to targeted endocrine therapies, and several key mechanisms likely play a role in that resistance, according to a speaker at the Endocrine Society annual meeting.

“Estrogen receptor is a key lineage determining transcription factor in the breast required for normal mammary gland development, and it is also essential for the growth of more than two-thirds of breast cancers,” Myles Brown, MD, director of the Center for Functional Cancer Epigenetics at the Dana-Farber Cancer Institute, and the Emil Frei III professor of medicine at Harvard Medical School, told Endocrine Today before his presidential plenary presentation. “Despite effective therapies to lower estrogen levels or block estrogen receptor action, most women with advanced estrogen receptor-positive breast cancer will become resistant to these endocrine therapies.”