Testosterone may suppress breast cancer cells

18 Jan 2021 17:15

Treating breast cancer with a substance that strongly resembles the ‘male sex hormone’ testosterone? This may be a solution for women who no longer respond to current hormone treatments. An international team including Wilbert Zwart’s research group seems to have found a definite answer to a long-standing question: what is the role of testosterone in breast cancer? Their results have been published in Nature Medicine today.

Approximately three quarters of women with breast cancer have a tumor that is hormone-sensitive. They can be given a treatment that suppresses their female sex hormones. This type of treatment is effective but causes side effects, and cancer cells can become resistant to the therapy.

Inhibit or activate?

For quite some time, physicians and scientists have suspected that the male sex hormone testosterone may play a role in breast cancer. However, despite all knowledge gained over the years on hormones and the way they bind to cell receptors, it was still unclear whether testosterone should be inhibited or activated in breast cancer treatment. Clinical trials involving breast cancer patients and testosterone receptor inhibitors have not proved successful as of yet.


The researchers hope to finally bring an end to this uncertainty. Using cells and tissue of patients, they have managed to prove that testosterone and a medicine similar to testosterone can be very effective in suppressing breast cancer cells. Intuitively this makes sense once you realize that testosterone inhibits breast growth during and after puberty. The medicine only mimics the effects of testosterone in the breasts, not elsewhere in the body. This means that women won’t develop masculine traits as a side effect.

Large group of patients

The medicine even proved effective in tissue samples taken from patients with tumors that were resistant to existing hormone therapies. One of the researchers, Wilbert Zwart, said: “Nearly every type of hormone-sensitive breast cancer may respond to this new therapy, which could eventually lead to an entirely new treatment option for this large group of patients.”

A clinical trial involving this treatment is currently running in Australia and the UK.

This research was made possible through the financial support of the Dutch Cancer Society.

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