Scientists Reclassify Breast Cancer Into 10 New Categories, Which Could Lead to Better Treatments
By Peter Russell
WebMD Health News
Reviewed by Sheena Meredith, MD
April 18, 2012 -- Doctors might one day be able to predict survival more accurately in women with breast cancer after reclassifying the disease into 10 new categories based on the genetic fingerprint of a tumor.
Scientists behind the latest research say the discovery amounts to a rewriting of the rule book on breast cancer and will allow more individually tailored treatment options for women with the disease.
The research, published in the journal Nature, is the largest global gene study of breast cancer tissue ever performed, and the culmination of decades of research into the disease.
A team at Cancer Research U.K.'s Cambridge Research Institute, in collaboration with the B.C. Cancer Agency in Vancouver, Canada, analyzed the DNA and RNA of 2,000 tumor samples taken from women diagnosed with breast cancer between five and 10 years ago.
Instead of examining these tumor samples under a microscope, they analyzed their genetic profile, hunting for genetic mutations that drive breast tumor development. The analysis uncovered several new breast cancer genes behind the disease, which the researchers say will be potential targets for the development of new types of drugs.
It also revealed the relationship between these genes and known cell activities that control cell growth and division. This could pinpoint how these gene mutations cause cancer, by disrupting important cell processes.
Individually Tailored Medication
The scientists say their analysis has allowed them to reclassify breast cancer into 10 new categories based on gene activity rather than the current tests done in laboratories, which look for the presence of indicators such as estrogen receptor (ER) or the cell surface receptor HER2. The researchers say this new classification could change the way medication is tailored to treat women with breast cancer.
"We've drilled down into the fundamental detail of the biological causes of breast cancer in a comprehensive genetic study," says one of the researchers, Carlos Caldas, MD, a professor at the University of Cambridge. "Based on our results we've reclassified breast cancer into 10 types, making breast cancer an umbrella term for an even greater number of diseases.
"Essentially we've moved from knowing what a breast tumor looks like under a microscope to pinpointing its molecular anatomy -- and eventually we'll know which drugs it will respond to."
"This research won't affect women diagnosed with breast cancer today. But in the future, breast cancer patients will receive treatment targeted to the genetic fingerprint of their tumor," Caldas says.
The researchers say the next stage will be to discover how tumors in each subgroup behave -- for example, do they grow or spread quickly?
Commenting on the study, Julia Wilson, PhD, head of research at Breakthrough Breast Cancer in the U.K., says in a statement: "This is incredibly exciting research, which has the potential to change the face of breast cancer; from how we diagnose and treat it, to how we follow it up afterwards. In essence the entire patient journey could change.
"This study is another important building block in our goal for women to receive personalized, tailor-made treatments specific to their particular type of breast cancer, rather than just a one-size-fits-all treatment approach."
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SOURCES: Caldas, C. Nature, published online April 18, 2012. News release, Cancer Research U.K. Julia Wilson, PhD, head of research, Breakthrough Breast Cancer, U.K.
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