Hormones, the KRAS-Variant & Breast Cancer Risk Study


“Hormones, the KRAS-variant and Breast Cancer Risk”

In 2012, founder Dr. Joanne Weidhaas led a study called “Hormones, the KRAS-variant and Breast Cancer Risk” with more than 1700 breast cancer survivors.


Dr. Weidhaas was able to learn about many of the women personally and their experiences with breast cancer. She found that by working directly with patients in the study, she was able to learn many critical pieces of information that may have been overlooked otherwise. Through this study and patient relationships, Dr. Weidhaas discovered a very important finding:

Estrogen protects women with the inherited KRAS-variant from cancer.

As our research studies suggest, hormone replacement therapy (HRT)iMedication that replaces the estrogen your body stops making during menopause. is protective for women with the inherited KRAS-variant.7 The use of estrogen as HRT during menopause has come with some controversy, due to a study in 2004,12 while more recent research suggests HRT can be a safe and healthy option for many women.13-16

Learn more about the KRAS-variant and how knowing your status can benefit you.

More about the study’s findings

The study’s most important findings were that for women with the inherited KRAS-variant, estrogen withdrawal and lower estrogen levels were significantly associated with a risk of developing aggressive breast cancer.

  • KRAS-variant breast cancer patients had lower body mass index (BMI), which results in lower circulating estrogen than KRAS-variant women without breast cancer.
  • Discontinuation of HRT in KRAS-variant patients was associated with a significantly higher risk of a breast cancer diagnosis of triple-negative breast cancer (TNBC).
  • KRAS-variant breast cancer patients were more likely to have had their ovaries removed before their breast cancer was diagnosed, suggesting that the sudden estrogen withdrawal caused by ovarian removal without estrogen replacement was a trigger for their breast cancer.

The findings of the study were published in 2015 in the scientific article “Estrogen Withdrawal, Increased Breast Cancer Risk and the KRAS-variant.” 7

Study results presented by Dr. Joanne Weidhaas

This study led to the creation of MiraKind

The “Hormones, the KRAS-variant and Breast Cancer Risk” Study was done in collaboration with the Army of Women, an organization that puts together breast cancer survivors and scientists. Through the generosity of their participation, Dr. Weidhaas was able to set out to search for answers with these breast cancer survivors regarding the association of the KRAS-variant, the genetic variant she co-discovered in 2006, estrogen use, and breast cancer.

The study was launched while she was on a one-year sabbatical at Stanford business school, and she loved interacting and engaging with these women to learn more about them, their journeys through life and battling cancer. She believes it was this approach in further studying the KRAS-variant — working directly with these patients — that allowed her to show how estrogen loss plays a role in breast cancer risk for women with the KRAS-variant.7

Prior research from Dr. Weidhaas’s laboratory and others had determined that the KRAS-variant was associated with an increased risk of developing certain cancers.1-6

As head of the breast cancer service at Yale and interacting with numerous patients with the KRAS-variant, it was clear to her that the KRAS-variant was a different type of genetic variant than other breast cancer variants. So she was especially motivated to learn about possible ways to help prevent cancer for these women.

This desire led to the “Hormones, the KRAS-variant and Breast Cancer Risk” study, which ultimately inspired her to start MiraKind, to enable her to work directly with patients to find the best answers for individuals with these new class of variants.


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Any discussion of medical management options on this website is for general informational purposes only and does not constitute a medical recommendation. All medical management decisions should be made based on consultation between each patient and his or her healthcare professional.

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