Molecular subtyping of breast cancer can better identify women at high risk of recurrence

March 6, 2014
Dr. Charles E. Cox, principal investigator of the molecular subtyping for breast cancer study, is a McCann-endowed professor of breast surgery at the University of South Florida Health Morsani College of Medicine, Tampa, FL. Credit: University of South Florida

A method called molecular subtyping can help doctors better determine which of their breast cancer patients are at high risk of getting breast cancer again, a new study led by the University of South Florida reports. This sophisticated genetic profiling of an individual's specific tumor offers an additional resource to help identify patients who would most benefit from chemotherapy and those who would not.

The findings by researchers from USF and other institutions were presented in a scientific poster at the Miami Breast Cancer Conference, held March 6-9 in Miami Beach, Fla.

"The most important takeaway for our colleagues in diagnosis and treatment is the potential value of molecular subtyping to personalize and improve each woman's treatment," said principal investigator Charles E. Cox, MD, McCann Foundation Endowed Professor of Breast Surgery, USF Health Morsani College of Medicine.

Molecular subtyping is a way of classifying breast cancer tumors into one of four genetically-distinct categories, or subtypes: Luminal A, Luminal B, Basal (a subset of triple negative), and HER2-type. Each subtype responds differently to different kinds of treatments, and some subtypes indicate a higher risk of disease .

"Our data showed that a substantial number of —classified as low risk by one particular genomic test—turn out to be at high risk of recurrence once we determined their subtype," Dr. Cox said. "These are mostly Luminal B patients, and their physicians might not fully understand their patient's situation unless they do subtyping."

The USF study examined why different genomic tests for breast cancer sometimes provide contradictory information about risk of recurrence. The key findings involved the 70-gene MammaPrint test; the 21-gene Oncotype DX test, which is an earlier commercially available test; and Mammostrat, a gene profiling test performed on slides of the breast tumor by a pathologist. The tests have generally been assumed to provide equivalent information about , but that is proving not to be the case.

The video will load shortly.
Dr. Charles Cox of the University of South Florida, Tampa FL, discusses the key findings of molecular subtyping for breast cancer study presented Mar. 6, 2014, at the annual Miami Breast Cancer Conference. Dr. Cox, the McCann Foundation-Endowed professor of breast surgery at the University of South Florida Health Morsani College of Medicine, reports that molecular subtyping helps to better identify high-risk breast cancer patients more prone to disease recurrence and, thus, more likely to benefit from chemotherapy following surgery. Credit: University of South Florida

Researchers examined tumor samples from a total of 148 patients. The greatest discordance (lack of agreement) about risk of occurred in a group of 51 patients. Of those 51, all were stratified by MammaPrint as high risk of recurrence, while Oncotype classified 18 of them (35 percent) as low risk.

BluePrint®, an 80-gene test to identify a tumor's molecular subtype, was also used for those stratified by MammaPrint. This process revealed that the 51 patients were Luminal B, a molecular subtype with a high risk of recurrence.

Patients with a high risk of recurrence are normally counseled to receive following surgery to prevent the cancer from returning. In contrast, women whose subtype has a low risk of recurrence (Luminal A) will not benefit from the addition of chemotherapy. They may thus be able to safely avoid chemotherapy and its potentially damaging side effects. At the same time, they can be prescribed treatments such as hormonal therapy known to benefit those with their subtype.

The additional information provided by genomic tests and molecular subtyping may help reduce overall treatment costs for breast cancer, by targeting chemotherapy only for those women who will benefit from it, Dr. Cox said "Personalized treatment guided by these tests may also extend the time that patients are free of their cancer."

Registered nurse George Ann Vincent, a Tampa, Fla. resident and a patient of Dr. Cox, was diagnosed with early-stage breast cancer last year. The 70-gene test determined that her tumor had a high risk of recurrence, so she was prescribed chemotherapy.

"I'm certainly grateful that I'm getting the treatments that are right for me," Vincent said. "Chemotherapy is no picnic, but it can save lives. The genomic tests I took made me confident I was being sent in absolutely the right direction."

Dr. Cox clarified that discordance does not necessarily show that some genomic test results were wrong.

"These tests use different genes and were validated on different types of populations," he said. "But if physicians use molecular subtyping as we did in this study, they will have valuable, additional information to guide the appropriate treatment for each patient."

Using molecular subtyping in combination with traditional biomarkers, like tumor grade and hormone receptor status, for determining the biological nature of a woman's cancer is a recommended guideline for in both the United States and Europe, Dr. Cox said.

Explore further: Breast cancer treatment selection is improved by genomic tests

Related Stories

Breast cancer treatment selection is improved by genomic tests

December 12, 2013
Genomic tests that determine the molecular subtype of a woman's breast cancer provide a more precise prognosis and valuable guidance about the best treatment, according to new research led by Massimo Cristofanilli, M.D, Director ...

Genomic study identifies subgroups of HER2+ breast cancer with varying sensitivities

January 17, 2014
Research led by the Translational Genomics Group at Vall d'Hebron Institute of Oncology (VHIO) in Barcelona has not only shown that HER2+ breast cancer can be classified into four different subtypes, but also unmasked a subtype ...

Smoking linked with increased risk of most common type of breast cancer

February 10, 2014
Young women who smoke and have been smoking a pack a day for a decade or more have a significantly increased risk of developing the most common type of breast cancer. That is the finding of an analysis published early online ...

Older patients with certain breast cancer subtype may not benefit from radiation therapy

April 2, 2012
Local breast radiation therapy may not be necessary for women with the luminal A subtype of breast cancer, particularly those aged older than 60, according to study results presented at the AACR Annual Meeting 2012, held ...

Breast cancer multi-gene tests compared

May 5, 2011
Two multi-gene tests designed to predict the risk of disease progression and response to chemotherapy in breast cancer produce broadly similar results for high- and low-risk patients, but do not always agree in their predictions ...

UNC Lineberger discovery goes from the lab to the patient with FDA approval

October 1, 2013
A laboratory testing kit that estimates the risk of breast cancer relapse in spite of anti-hormone treatment has received approval from the U.S. Food and Drug Administration (FDA). This technology is based on a gene signature ...

Recommended for you

Scientists develop blood test that spots tumor-derived DNA in people with early-stage cancers

August 16, 2017
In a bid to detect cancers early and in a noninvasive way, scientists at the Johns Hopkins Kimmel Cancer Center report they have developed a test that spots tiny amounts of cancer-specific DNA in blood and have used it to ...

Toxic formaldehyde is produced inside our own cells, scientists discover

August 16, 2017
New research has revealed that some of the toxin formaldehyde in our bodies does not come from our environment - it is a by-product of an essential reaction inside our own cells. This could provide new targets for developing ...

Cell cycle-blocking drugs can shrink tumors by enlisting immune system in attack on cancer

August 16, 2017
In the brief time that drugs known as CDK4/6 inhibitors have been approved for the treatment of metastatic breast cancer, doctors have made a startling observation: in certain patients, the drugs—designed to halt cancer ...

Researchers find 'switch' that turns on immune cells' tumor-killing ability

August 16, 2017
Molecular biologists led by Leonid Pobezinsky and his wife and research collaborator Elena Pobezinskaya at the University of Massachusetts Amherst have published results that for the first time show how a microRNA molecule ...

Popular immunotherapy target turns out to have a surprising buddy

August 16, 2017
The majority of current cancer immunotherapies focus on PD-L1. This well studied protein turns out to be controlled by a partner, CMTM6, a previously unexplored molecule that is now suddenly also a potential therapeutic target. ...

A metabolic treatment for pancreatic cancer?

August 15, 2017
Pancreatic cancer is now the third leading cause of cancer mortality. Its incidence is increasing in parallel with the population increase in obesity, and its five-year survival rate still hovers at just 8 to 9 percent. Research ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.