Adding Progesterone To Breast Cancer Treatment May Slow Cell Growth In Nearly Half Of All Patients

Breast cancer
Promising lab research may lead to better, hormone-driven breast cancer treatment. Jimmy Baikovicius, CC BY-SA 2.0

Some breast cancers are driven by female hormones, estrogen and progesterone — and with regard to progesterone, a new study believes adding it to treatment may help patients live longer.

Hormone-driven breast cancer cells have receptors on the outside of their walls, the Mayo Clinic reported; this is also referred to as hormone receptor-positive(HR) cancer. These receptors catch specific hormones circulating throughout the body. Estrogen receptors (ER) catch estrogen, and progesterone receptors (PR) catch progesterone. And according to the American Cancer Society, “about two out of three of breast cancers are [HR]-positive.”

The present study was interested to see where exactly these receptors attach to the DNA responsible for driving cancer cell growth. With advanced DNA reading technology, they did just that. Then, the team grew breast cancer cells that had been rescued for research purposes with and without progesterone, Medical News Today reported. MNT added this is a new technique developed at the University of Adelaide in Australia.

The results showed when the PR is activated it redirects the ER to different DNA regions, in which a different set of genes works to slow cell growth. And given the number of patients with HR-positive cancer (it’s possible to have HR receptor-negative cancer) these findings suggest a progesterone-type treatment could go on to benefit around half of breast cancer patients.

Though it’s too early to translate these lab findings to humans, Dr. Jason Carroll, senior study author and principal investigator at the Carroll Lab Cambridge Research Institute in the UK, told MNT it’s enough to at least start thinking about it.

"Crucially, it provides a strong case for a clinical trial to investigate the potential benefit of adding progesterone to drugs that target the [ER], which could improve treatment for the majority of hormone-driven breast cancers," Carroll said. "We've used cutting-edge technology to tease out the crucial role that progesterone receptors play in breast cancer — a mystery that has baffled scientists for many years."

The Mayo Clinic added patients knowing their breast cancer is sensitive to hormones gives their doctor a better idea of how to treat them, as well as prevent future cases. Currently, Tamoxifen is the drug commonly prescribed to treat ER-positive cancer. The ACS explained it can be given for five to 10 years after patient surgery to lower the chances of the cancer coming back, ultimately helping them live longer.

Source: Tilley W.D., Carroll J, et al. Progesterone receptor modulates ERα action in breast cancer. Nature. 2015.

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