Molecular Methods Differentiate Breast Cancers

By analyzing the DNA and ribonucleic acid (RNA) from breast cancer tumors, it is proposed that what are called breast cancer are in fact at least 10 different diseases, each with its own molecular fingerprint and pattern of weak spots.

In a landmark study that promises to revolutionize diagnosis and prognosis, and pave the way for individualized, tailored treatment, British and Canadian scientists uncovered crucial new information about breast cancer. The scientists analyzed the DNA and RNA of breast tumor samples from nearly 2,000 women who had been diagnosed between 5 and 10 years ago, and for whom information about the tumor characteristics had been meticulously recorded. The teams were from the Cambridge Research Institute (UK) and British Columbia Cancer Center (Vancouver, BC, Canada).

The team performed analyses on the DNA of the tumors--for instance, the map is now annotated with copy number changes and single letter variations or single-nucleotide polymorphism, for each tumor. The scientists also conducted a detailed analysis of the tumor RNA so they can tell which genes were active in each sample. Altogether, they did this for more than 30,000 types of RNA, each corresponding to the activity of a single gene.

The study revealed the relationship between breast cancer genes and known signaling pathways, the networks that control cell growth and division. This invaluable knowledge will help identify how variants of these genes cause cancer by interfering with cell processes. The team also discovered several previously unknown genes that drive breast cancer. Each of these is a potential target for new drugs, and should boost worldwide efforts to discover and develop new treatments.

Carlos Caldas, MD, professor of Cancer Medicine at Cambridge said, "We've drilled down into the fundamental detail of the biological causes of breast cancer, and we've moved from knowing what a breast tumor looks like under a microscope to pinpointing its molecular anatomy. Our results will pave the way for doctors in the future to diagnose the type of breast cancer a woman has, the types of drugs that will work, and those that won't, in a much more precise way than is currently possible." The study was published in the April 18, 2012, online issue of Nature.

Related Links:
Cambridge Research Institute
British Columbia Cancer Center