Used as a Biomarker, MicroRNA May Help Predict Which Patients With Breast Cancer Are More Likely to Have Cancer Recurrence

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MicroRNA may be used as a biomarker to predict which patients are likely to face breast cancer recurrence and mortality, according to a new study published by Davey et al in the Journal of the American College of Surgeons.

While long-term outcomes have improved for patients with breast cancer, 20% to 30% of these patients will see their breast cancer recur. The process of identifying which patients are more likely to have a recurrence has been a challenge. Therefore, researchers set out to determine whether microRNA can be used to predict which patients are more likely to experience breast cancer recurrence and, ultimately, mortality.

The researchers discovered that patients with an increased expression of miR-145—a certain type of microRNA—were unlikely to have a recurrence of breast cancer because miR-145 inhibited the development and progression of cancer.

“We showed that increased expression of this biomarker, which was measured in patients’ blood samples during chemotherapy, actually predicted their long-term oncological outcome,” said first study author Matthew G. Davey, MRCSI, PhD, a researcher in the Department of Surgery at the Lambe Institute for Translational Research at the National University of Ireland Galway. “We can predict those who are likely to suffer recurrence and those who will be free of recurrence.”

The researchers believed that miR-145 could help identify patients who could benefit from closer breast cancer surveillance and a tailored care strategy in the postoperative phase of treatment, as well as those who are at lower risk of recurrence and may not need systemic treatments—which often can have harmful side effects.

“This biomarker will help us give the right treatments to the right patients,” said study coauthor Michael J. Kerin, MCh, FRCSI, FRCSED, Chair of the Department of Surgery at the Lambe Institute for Translational Research at the National University of Ireland Galway.

Study Methodology and Findings

The prospective, multicenter trial recruited 124 patients who were treated with standard-of-care neoadjuvant chemotherapy for localized breast cancer in eight independent treatment sites across Ireland. The type of chemotherapy varied according to the judgment of the patient’s health-care team.

Blood samples were collected from the patients over a 3-year period at diagnosis and halfway through chemotherapy treatment. To establish their roles in predicting whether the patients would be free of recurrence of disease and their overall survival, microRNA expression levels were evaluated at each time point.

The study found that increased miR-145 expression correlated with improved outcomes at a follow-up of almost 9 years. Increased miR-145 independently predicted improved recurrence-free survival (hazard ratio [HR] = 0.00, 95% confidence interval [CI] = 0.00–0.99, P = .05) and trended toward improved disease-free survival (HR = 0.00, 95% CI = 0.00–1.42, P = .067) when statistical analyses were performed. Increased miR-145 expression levels did not predict overall survival.

Future Research Opportunities

For the study, the researchers looked at patients who had any of the five subtypes of breast cancer, though the study was not designed to determine how effective miR-145 was at predicting outcomes for any particular subtype of breast cancer. The researchers are planning to conduct further clinical trials to help predict these outcomes.

There is also research underway to see if the expression of microRNA could be increased in patients with breast cancer. For instance, “One trial is testing [micro]RNA replacement therapies in mice, but the research is in its early stages, and it is unclear if the therapy could be transferred to humans,” Dr. Kerin said.

Dr. Davey and colleagues hope to conduct an additional trial in which the researchers will focus on patients with HER2-positive breast cancer.

Disclosure: For full disclosures of the study authors, visit

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