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Breast Cancer: Hormonal Influences

Breast Cancer: Hormonal Influences
February 10, 2018 Writing Department
  • estrogen-progesterone-breast-cancer

Estrogen, Progesterone And Breast Health

note: the information on this page for apoptosis applies to all forms of cancer.

What Effect do Hormones Have?

Molecular biologist, Dr. Ben Formby of Copenhagen, Denmark and Dr. T.S. Wiley at the University of California in Santa Barbara have researched two genes, BCL2 and P53, and their effect on female-specific cancers and prostate cancer.

The Research

Cells of breast, endometrium, ovary and prostate, were grown in the laboratory. Estrogen (estradiol) was added to the cells. This hormone turned on the BCL2 gene, causing the cells to grow rapidly and not die on time. Then, progesterone was added to the cell cultures. Cell reproduction stopped and the cells died on time (apoptosis).

This methodology was applied to all the above types of cancer.

The Measured Effect

The BCL2 gene, therefore, stimulates the growth of these cells and the risk of cancer. On the other hand, the P53 gene promotes apoptosis or programmed cell death and thereby, reduces the risk of cancer. Estradiol upregulates or stimulates the production of the BCL2 gene, while progesterone upregulates or stimulates the production of the P53 gene.

Transdermal estradiol increased the cell proliferation rate by 230%, while transdermal progesterone decreased the cell proliferation rate by >400%. A combination estradiol/progesterone cream maintained the normal proliferation rate. This is direct evidence that estradiol (a potent estrogen) stimulates hyper-proliferation of breast tissue cells and progesterone mediates hyper-proliferation.

Further Research

A second study by noted researcher Bent Formby, Ph.D. was published with more insightful results.

To determine the biologic mechanism of why progesterone inhibits the proliferation of breast cancer cells, a variety of cancer cell lines with different receptors and different expression of genes were exposed to progesterone. Exposure to progesterone induced a 90% inhibition of cell proliferation in T47-D breast cancer cells and no measurable response to MDA-231 progesterone-receptor negative breast cancer cells. An impressive 43% of the T47-D cancer cells had undergone apoptosis (programmed cell death) within 24 hours after exposure to progesterone.

Further analysis showed that the genetic expression by T47-D cancer cells of the BCL2 gene was down-regulated, and that of the p53 gene (tumor suppressor gene) was up-regulated.

Since the p53 gene expression induces cell apoptosis and the BCL2 gene when expressed inhibits apoptosis, if one’s cancer cells are progesterone-receptor positive, then, as part of one’s therapy, progesterone plays a very important role in treatment. However, 50% of breast cancer cell lines have mutant or no p53 oncogene expression, so in this instance, genistein therapy might be helpful.


Therefore unopposed estradiol causes these same types of cancer. Since Breast cancer is considered to be a hormone dependent cancer it is critically important to avoid the factors that would promote too much estradiol.

Birth Control: Vital Information for Breast Cancer

In order for natural progesterone to stimulate the production of the P53 gene it must attach itself to progesterone receptors found in abundance in breast, ovarian, and endometrial cells.

If a woman is taking birth control pills or any other form of synthetic progesterones (progestins, progesterone acetate, medroxy-progesterone acetate) these synthetic progesterones will occupy progesterone receptors and prevent natural progesterone from occupying the receptor site.

Synthetic progesterones not only fail to produce the P53 gene but prevent it’s production by blocking natural progesterone from occupying the progesterone receptor and in the presence of excess estradiol, dramatically increase a woman’s risk for female-specific cancers.

There are 12 references to tests on BCL2 and P53, and how they are affected by progesterone & estrogen. This information has been published, in part, in the following journals:

  • The American Cancer Society Journal
  • The Journal of Clinical Endocrinology
  • The American Journal of Pathology
  • International Journal of Cancer
  • The Journal of the American Medical Association (JAMA)
  • Fertility and Sterility – Journal of the American Society For Reproductive Medicine


Clearly, a primary, underlying cause of breast cancer is too much estrogen and its production of the BCL2 gene, relative to too little of the helpful benefits of natural progesterone and its production of the P53 gene.

Comments (2)

  1. Eulaine mc 3 years ago

    Short term use of these. Is this still dangerous?

    • Author
      Writing Team 3 years ago

      if you read the entire article, you will draw a healthy conclusion…

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