New research published this week, and reported in the media, could help identify women with triple negative breast cancer (TNBC) who are most at risk of their breast cancer coming back.

Tuesday 3 March 2015      Research blog

New research published this week, and reported in the media, could help identify women with triple negative breast cancer (TNBC) who are most at risk of their breast cancer coming back.  The findings also give new insight into the biology of this aggressive form of the disease.  We take a closer look at the research and the potential impact it could have for women with breast cancer.

Preventing the return of breast cancer

In this study, funded by Breakthrough Breast Cancer, the Institute of Cancer Research and Cancer Research UK, scientists went on the hunt for a genetic signature which could accurately identify patients most at risk of their cancer coming back after treatment.  They were particularly interested in triple negative breast cancers as these patients tend to have higher rates of recurrence than those with other types of breast cancer.

It’s extremely important that we can predict who is likely to relapse so that more can be done to protect these patients.  Closer monitoring of high risk patients or extended treatment could help reduce the chance of their cancer coming back.

Genetics of “stem-ness”

The researchers thought that a way to identify these at-risk women could be found by looking at the genetics of stem cells found in breast tissue.  Stem cells and their role in cancer have been mentioned a lot lately and we’ve previously written about them on the blog.  TNBCs often contain high numbers of breast cancer stem cells, and by looking at the genetics of normal mammary stem cells it was hoped that a predictive gene signature could be found.

Using stem cells isolated from the mammary tissue of mice, the researchers were able to find a signature of 323 genes that were all switched on at high levels compared to other cell types found in the mammary tissue.  Mouse and human genetics are virtually identical, so for every one of these 323 genes it is possible to match it up to a corresponding human gene.  Looking at the genetics of tumours donated by triple negative breast cancer patients, it became apparent that the human equivalent of the gene signature was present in breast cancer cases where recurrence had occurred within five years of treatment ending.

Programmed to spread

This is very intriguing because it suggests that the triple negative tumours likely to recur are mimicking a gene signature present in breast stem cells, and that this signature may have the power to predict recurrence.  It could be that the gene signature acts like a program, telling TNBC cells to behave more like stem cells - a property which we know is associated with resistance to treatment, recurrence and, ultimately, secondary breast cancer.

When the researchers probed deeper into the set of 323 genes, they found that the signature contained a lot of genes known to control cellular process associated with the spread of breast cancer.  For example, some of the genes control how cancer cells interact with nearby cells while others control the cells’ ability to move around.  This would suggests that a sub-set of the 323 genes may be responsible for the aggressive nature of TNBC.  Further research into these genes may lead to new targeted drugs that can prevent the growth and spread of the disease.

Better care for patients

As we’ve mentioned before, the triple negative category of breast cancers has become a dumping ground for many different but overlapping types of breast cancer.  Identifying a set of genes unique to a subset of TNBC patients shows us how we can refine the definitions of the disease and potentially improve how these patients are cared for. 

Research like this ensures that, in the future, patients will receive a more accurate diagnosis. It also gives us hope that effective targeted treatments can be developed for this hard-to-treat form of breast cancer.  With more than 5000 women expected to be diagnosed each year with TNBC, the need for these discoveries is as vital as ever.

Dr Matthew Lam is Breakthrough Breast Cancer's Senior Research Officer