Can Blood Test Predict Breast Cancer Risk?

A blood test that spots changes in a specific gene could reveal a woman's risk for breast cancer years before the disease has a chance to develop, researchers report.
British scientists analyzed blood samples from 640 breast cancer patients and 741 women without breast cancer. The samples from the breast cancer patients were collected an average of three years before they were diagnosed with the disease.
The objective was to find out if the alteration of single genes by a process called methylation could predict a woman's breast cancer risk.
The researchers found that women with the highest level of methylation on one area of a gene called ATM were two times more likely to develop cancer than those with the lowest level of methylation. Methylation is a critical process where chemicals known as "methyl groups" are added to DNA, to make sure everything is in good working order. High levels of methylation signal high levels of DNA trouble.
This result was particularly pronounced in blood samples taken from women under the age of 60, Dr. James Flanagan, a Breast Cancer Campaign scientific fellow in the department of surgery and cancer at Imperial College London, said in a news release from the Breast Cancer Campaign.
The study was published May 1 in the journal Cancer Research.
Unlike previous studies that took blood from breast cancer patients after diagnosis, these blood samples identified alterations in the ATM gene that did not occur because of having active cancer or cancer treatments.
The findings provide strong evidence that looking for this type of alteration in individual genes could be used as a blood test to help predict a woman's chances of developing breast cancer, the researchers said.
Used in combination with other breast cancer risk assessment tools such as genetic testing and risk factor profiling, this blood test could help identify women at higher risk. This early warning could be used to monitor these patients and one day perhaps even prevent them from developing breast cancer.
"We know that genetic variation contributes to a person's risk of disease. With this new study, we can now also say that epigenetic variation, or differences in how genes are modified, also has a role," Flanagan said.
"We hope that this research is just the beginning of our understanding about the epigenetic component of breast cancer risk, and in the coming years we hope to find many more examples of genes that contribute to a person's risk. The challenge will be how to incorporate all of this new information into the computer models that are currently used for individual risk prediction," he noted.
"So far, we have found alterations in one small region of a gene that appear to associate with risk of disease, and so the next step with this epigenetic research is a genome-wide approach to try and find all the associated genes," Flanagan explained.
More information
The American Cancer Society has more about breast cancer risk factors.