How Contraceptives Prevent Breast Cancer?

Breast cancer is a disease in which cells in the breast grow out of control risk increases with the use of hormone replacement therapy (those that include both estrogen and progesterone) during menopause and oral contraceptives (birth control pills) for more than five years. Hormonal contraceptives (the pill, the patch, and the vaginal ring) contain a small amount of human-made estrogen and progestin hormones to prevent pregnancy by either blocking ovulation process or making the cervical mucus difficult for the sperm to go through the cervix or changing the lining of the womb to avoid implantation of fertilized egg.

Eventhough hormonal contraceptives increase the risk of breast cancer, a team of scientists led by Professor Cathrin Brisken at EPFL's School of Life Sciences studies different biological effects of different progestins in hormonal contraceptives on the breast tissue - the mammary epithelium published in EMBO Molecular Medicine.

"We found that HBECs engraft and proliferate in mouse milk ducts, maintaining hormone receptor expression and hormone responsiveness, which are crucial factors for establishing a relevant preclinical model and thereby to foster translational research," says Brisken.

To tested the effects of different progestins on human breast epithelial cells or HBECs, they developed "humanized" mouse mammary glands by grafting breast epithelial cells from donated from reduction mammoplasty human breast samples into the animals' milk ducts and monitoring their growth in vivo.

The study shows that only progestins promote cell proliferation through the androgen receptor to induce the expression of the protein Rankl, which plays an important role in cell proliferation in the mammary epithelium.

This finding makes women to prefer hormonal contraceptive with non-androgenic progestin to reduce the breast cancer risk.

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Source-Medindia