Tamoxifen resistance linked to high estrogen levels in utero

Posted December 9, 2016

An animal study suggests that resistance to tamoxifen therapy in some estrogen receptor positive breast cancers may originate from in utero exposure to endocrine disrupting chemicals. The study provides a new path forward in human research as about half of the breast cancers treated with this common cancer therapy do not respond well, say researchers at the Georgetown Lombardi Comprehensive Cancer Center, who led the multi-institutional research.

The study, published in the Journal of the National Cancer Institute (JNCI), identified four genes that are linked to tamoxifen resistance and poor prognosis of breast cancer, by comparing results obtained in a new animal model, in human breast cancer cells grown in culture, and in publically available datasets collected from thousands of estrogen receptor positive breast cancer patients treated with tamoxifen.