The Cancer Genome Atlas reports on four breast cancer subtypes, in Nature. The researchers examined tumor and germline DNA from 825 patients using a number of different approaches, including mRNA expression microarrays DNA methylation chips, and whole-exome sequencing, among others. From this profiling, the researchers found that mutations in only three genes, TP53, PIK3CA, and GATA3, occurred in more than 10 percent of breast tumors. But, they note, there are certain subtypes have specific mutations and enrichment of certain mutations. They write that "our ability to integrate information across platforms provided key insights into previously defined gene expression subtypes and demonstrated the existence of four main breast cancer classes when combining data from five platforms, each of which shows significant molecular heterogeneity." Those four subtypes are: HER2-enriched, luminal A, luminal B, and basal-like breast cancers.
The New York Times adds that such knowledge of breast cancer subtypes may lead to better treatments. "This is the road map for how we might cure breast cancer in the future," Matthew Ellis from Washington University tells the Times.
Our sister publication GenomeWeb Daily News has more on the TCGA study here.