Mifepristone, also known as RU-486, which is used to abort pregnancy, could be used to halt the development of certain cancers, including breast and ovarian cancers, say researchers form the University of California at Irvine, USA.
Mifepristone blocks the action of progesterone during the first three months of pregnancy, effectively leading to the death of the embryo/foetus. Progesterone is also nourishment for some types of cancer, without which they cannot grow. At a lower dose, Mifepristone can also be an emergency contraceptive.
You can read about this latest study in the journal Science.
The researchers, after carrying out studies on mice, believe that RU-486 may be beneficial for women who have a genetic propensity to developing cancer. Over 50% of women who carry a faulty BRCA1 gene will have either breast or ovarian cancer by their 70th birthday.
In this study, the scientists examined mice which had been genetically engineered to lack the BRCA1 gene. They discovered that the mammary glands of these mice built up more progesterone receptors. Progesterone receptors are molecules that allow progesterone to become effective. The progesterone attaches itself to these receptors and encourages cells to grow abnormally. All the mice had tumours by the time they were eight months’ old.
However, half the genetically engineered mice had been treated with mifepristone – and none of these mice went on to develop tumors.
The trouble is, say the scientists, that mifepristone has an effect on other receptors as well. Meaning, mifepristone has some unpleasant side effects. They plan further research which might eventually target just the progesterone blocking action. This could lead to treatment which would prevent breast and ovarian cancers among women who carry the faulty BRAC1 gene.
“Prevention of Brca1-Mediated Mammary Tumorigenesis in Mice by a Progesterone Antagonist”
Aleksandra Jovanovic Poole, Ying Li, Yoon Kim, Suh-Chin J. Lin, Wen-Hwa Lee, Eva Y.-H. P. Lee
Science 1 December 2006 Vol. 314. no. 5804, pp. 1467 – 1470
DOI: 10.1126/science.1130471
Written by: Christian Nordqvist
Editor: Medical News Today