Breast cancer gets genetic profile

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http://www.sciencenews.org/view/generic/id/345377/title/Breast_cancer_gets_genetic_profile

One of the most complete portraits of breast cancer yet painted may inspire some new treatment options.

Doctors and researchers have long classified breast cancer into four different types. But those sketches contain information about only one aspect of tumors and do not show all facets of the cancer’s molecular personality, including mutations, protein production and levels of genetic activity. Now, an international consortium of researchers known as the Cancer Genome Atlas Network has combined many different types of data to fill in the picture, including the mutations that probably sparked tumor formation in the first place. The molecular portraits were published online September 23 in Nature.

Breast cancers are usually categorized by which genes are highly active. Tumors with an overactive estrogen receptor gene are known as ER-positive and fall into two groups: the easier-to-treat luminal A group and a more aggressive luminal B group. Another category is based on the activity of the HER2 gene.

The fourth category, basal-like tumors, sometimes called triple-negative tumors, is different from the rest. This type of breast cancer is aggressive, tends to strike younger women, African-Americans and women with a family history of the disease. It is also associated with mutations in the BRCA1 gene, which are associated with a greatly increased risk of breast cancer.