DNA marker explains differences in breast cancer among races, could lead to new therapies
Researchers have discovered a potential explanation for the varied experiences women of different races have with breast cancer. While breast cancer is more common in Caucasian women than in African American women, it's African American women who often experience a more aggressive form of the disease, leading to a much lower survival rate than that of Caucasian women.
To find out why, a team of researchers and doctors at the North Shore-LIJ Health System and the Feinstein Institute for Medical Research profiled blood from 32 patients before the removal of breast tumors, including that of 12 control patients and 20 women with a form of stage III breast cancer. They tested the genetic markers embedded in DNA, called microRNA, which are known to differ between Caucasian and African American women.
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They found that Caucasian women who had triple-negative breast cancer - meaning any breast cancer that does not express the three receptors that are known to advance the cancer - showed levels of 20 different microRNA that were 15 times higher than the control group, and none of these microRNA were found in any of the African American patients.
The African American women showed overexpression of only six microRNA, each still 15 times higher than the control group, and none of these microRNA were found in the Caucasian women.
"Breast cancer patients who have the most devastating outcome may carry the microRNAs that promote cancer. What we saw in this study is that Caucasian women may carry microRNAs that protect against cancer while African American women do not express those microRNAs," said Iuliana Shapira, director of the Cancer Genetics Program at the North Shore-LIJ Health System's Monter Cancer Center. "Methods to increase microRNAs in the blood before surgery for cancer, such as giving chemotherapy before surgery for cancer, may improve survival rates in African American women with triple-negative breast cancer."
Shapira said the team has applied for a government grant to further validate these markers and inform future therapies with more personalized data.
"Understanding the changes in microRNA throughout chemotherapy treatment helps us better understand ovarian cancer and how best to treat patients who have this disease," said Annette Lee, PhD, associate investigator at the Feinstein Institute. "The genetic markers we identified allow patients to individualize their own therapy in order to have maximum benefit and minimal side effects. In addition, this knowledge will help researchers develop new treatments for patients with ovarian cancer."
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