Genetic Variant Protects Some Latina Women from Breast Cancer

Medical Xpress, October 20, 2014

An international research collaboration led by UC San Francisco researchers has identified a genetic variant common in Latina women that protects against breast cancer.

The variant, a difference in just one of the three billion “letters” in the human genome known as a single-nucleotide polymorphism (SNP), originates from indigenous Americans and confers significant protection from breast cancer, particularly the more aggressive estrogen receptor-negative forms of the disease, which generally have a worse prognosis.

“The effect is quite significant,” said Elad Ziv, MD, professor of medicine and senior author of the study. “If you have one copy of this variant, which is the case for approximately 20% (the range being 10 to 25 percent) of U.S. Latinas, you are about 40 percent less likely to have breast cancer. If you have two copies, which occurs in approximately 1% of the US Latina population, the reduction in risk is on the order of 80 percent.”

Published in the October 20, 2014 issue of Nature Communications, the new study showed that women who carry the variant have breast tissue that appears less dense on mammograms. High “mammographic density” is a known risk factor for breast cancer.

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Epidemiological data have long demonstrated that Latina women are less susceptible to breast cancer than women of other ethnicities. According to National Cancer Institute data from 2007 to 2009, whites have about a 13 percent lifetime risk of breast cancer, blacks about 11 percent, and Hispanics less than 10 percent. The lifetime risk among Hispanics with indigenous American ancestry is even lower.

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The newly discovered SNP is on Chromosome 6, near a gene coding for an estrogen receptor known as ESR1. Fejerman and Ziv said that the biological basis of the association between the variant and reduced breast cancer risk is still not known, but their preliminary experiments indicate that the variant interferes with the action of transcription factors, proteins that regulate the expression of the ESR1 estrogen receptor.

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  • Tim_in_Indiana

    No offense intended, but I’m wondering why we’re constantly hearing about breast cancer, seeing those little pink ribbons everywhere, when heart disease kills many, many times more people than breast cancer? Is it because heart disease kills primarily men??

    • Pink ribbons, because you care about breast cancer.

      And you care because you care.

      It’s about time that someone stood up David like to the all powerful Goliath that is the cabal of people that hate women with breast cancer and want them all to die.

      Next up…the Twitter hashtag.

      What, don’t you care?

      • Tim_in_Indiana

        Who said anyone didn’t care about women? Or are you just projecting?

        • As I get less and less young, I become all the less impressed with symbolism.

    • M.

      “Heart disease is the leading cause of death among women.”

      “Every year, coronary heart disease, the single biggest cause of death in the United States, claims women and men in nearly equal numbers, totaling about 500,000 lives.”

      http://www(dot)health(dot)harvard(dot)edu/newsweek/Gender_matters_Heart_disease_risk_in_women(dot)htm

      Now as to why there’s more focus on breast cancer than heart disease, that I don’t know. Although there is much talk about obesity, which is usually linked to heart disease.

      • Tim_in_Indiana

        WebMD: Heart disease kills half a million American women each year. So why are women more afraid of breast cancer?

        http:// www. webmd. com /heart-disease/features/women-more-afraid-of-breast-cancer-than-heart-disease

        • none of your business

          Because women mostly die of heart disease after 75. Cancer can kill younger people. Getting a deadly disease at 30 is far worse than getting it at 70. Then too, heart disease often can be cured without surgery.

        • Who Me?

          Why are women so afraid of breast cancer?
          Well, if men got testicular cancer at the rate women get breast cancer, wouldn’t you be a little bit more concerned about it too?

          • LHathaway

            I believe I’ve read that prostate cancer occurs more often than breast cancer.

    • willbest

      While I agree that Breast Cancer is completely overhyped relative to the risk, I will point out that the bulk of heart disease cases fall into two categories.

      1) Lifestyle choices resulting in arterial damage (ie. Own Damn Fault)
      2) Being old. Nobody dies of old age anymore. Case in point, my grandpa died at age 88 of a heart attack, but he was playing 18 holes a couple times a month at 84.

  • M.

    Good for them. However, there’s a reason this gene, or genetic variant, isn’t more widespread among Latinos, and that is because most women who get breast cancer have it after the menopause, which means that this mutation only confered an evolutionary advantage to the small minority of women who get it while still fertile.

    I wonder if this variant will be found in some American whites, especially those who might have Indian ancestry. And if so, will genetic engineering get so advanced that it would “implemented” in all newborns? Not that implausible in the future. People can already choose which eye and hair color they want to pass to their progeny.

  • Not much to say here except that once again science proves the sociologists wrong. Race is not a social construct. It’s in your genes.

  • Extropico

    This evidence of the advent of a single nucleotide polymorphism that confers resistance to breast cancer is a social construct. There is no race. There is no morphism that could possibly be ascribed to geographic and racial groupings of any kind. Any nucleotide morphism, whether beneficial or maledict, must occur coterminously within the ambit of the current social construct of the definition of humanity.

    If a grouping of bipeds acquires an evolutionary nucleotide advantage that remains unshared for a time expatiated upon at certain meetings held by the Ministry of Truth, that grouping of bipeds must not be included within a depiction of humans.

  • Alexandra1973

    I’ve read that if a woman starts having babies in her early 20s, she’ll be less likely to have breast cancer.

    And we’re talking Latinas here.

    On that note–iodine also helps prevent breast cancer.

    • none of your business

      That is true, but it is just one of several indications; normal weight, medium size breasts and most, most of all the biggest indicator for cancer of any kind. Did your parents or any other ancestors have any form of cancer.

      • M.

        “most of all the biggest indicator for cancer of any kind. Did your parents or any other ancestors have any form of cancer.”

        I may have misunderstood, but are you suggesting that heredity is the most important factor in all cancers? If so, that’s not the case for lung cancer. Smoking is linked to 90% of lung cancers, and smokers are 15 to 30 times more likely to develop that particular cancer.

        http://www(dot)cdc(dot)gov/cancer/lung/basic_info/risk_factors(dot)htm

        • none of your business

          yes, it is true that heredity is the most important factor in cancer. During the lawsuits against the tobacco companies, the companies, the defendants proved that virtually all the smokers who developed lung, throat and thyroid cancer because of smoking came from families prone to cancer.
          Most smokers, even those who smoke 3 packs a day for 50 years do not develop lung and throat cancer.

    • HisGirl

      It’s not just having babies, it’s breastfeeding them. And that means in an evolutionarily-appropriate way, i.e. full time, around the clock, for at least one year per baby. Doing so cuts your risk of breast cancer dramatically, regardless of other risk factors. It’s a striking illustration of the saying, “Use it or lose it.”

      • none of your business

        That is a statistical factor which is meaningless to the individual. Having babies and breast feeding does not cut the risk of breast cancer. There are 4 factors in breast cancer, weight, breast size, childbirth and heredity.
        Being fat, having large breasts and never having children are just indicators for breast cancer Normal weight and breast size and childbirth are just indicators for not having breast cancer..
        Heredity is the main factor.
        Go to the professional nurse’s and Drs websites and or medical and nursing textbooks for more info.
        Much of the info for laymen is just a form of advertising to encourage women to get mammograms every year and make more money for the providers.
        Heredity is the factor in most diseases.
        A lot of the information for laymen re:health is just Oprah style “you can control your own destiny” liberal junk. You know, become a vegetarian and buy your food at 4 times the price of ordinary supermarkets and you will live until you are 100 and be jogging right up to the day you die.

        • HisGirl

          Pure fatalism. Regardless of whether an individual has hereditary risk factors for breast cancer, she can minimize her chances of actually developing it by making the right lifestyle choices. She may still get it anyway, but I’ll take the better odds any day.

          • none of your business

            It’s not fatalism, it is the scientific medical truth. Did you read the article? It states that some women will not get breast cancer because of their genes.

          • HisGirl

            But I’m not talking about those women. I’m talking about the ones who DO have the cancer genes. And unless we implement universal genetic screening, that could be any of us. I prefer to optimize my chances. The things I mentioned are some of the ways to do that.

  • none of your business

    Nice for Hispanic women but who cares? Why is this article posted?

  • none of your business

    Ultimately, heart disease kills everybody. But with modern medical care men no longer die of their first stroke at age 40.

  • The obsession with genes including the money available for that obsession clouds the various environmental factors which contribute to gene expression or lack thereof. Native Americans have generations of tradition of breastfeeding–longer than what most civilized peoples do today. Dietary factors in terms of civilized vs. traditional foods and even clothing choice may also impact the results. However, given that gene therapy is supposed to be a huge moneymaker, count on more and more studies justifying it over lifestyle choices.