Hereditary Breast and Ovarian Cancers: Moving Toward More Precise Prevention

Homologous Hope sculpture

Caption: “Homologous Hope” sculpture at University of Pennsylvania depicting the part of the BRCA2 gene involved in DNA repair.
Credit: Dan Burke Photography/Penn Medicine

Inherited mutations in the BRCA1 gene and closely related BRCA2 gene account for about 5 to 10 percent of all breast cancers and 15 percent of ovarian cancers [1]. For any given individual, the likelihood that one of these mutations is responsible goes up significantly in the presence of  a strong family history of developing such cancers at a relatively early age. Recently, actress Angelina Jolie revealed that she’d had her ovaries removed to reduce her risk of ovarian cancer—news that follows her courageous disclosure a couple of years ago that she’d undergone a prophylactic double mastectomy after learning she’d inherited a mutated version of BRCA1.

As life-saving as genetic testing and preventive surgery may be for certain individuals, it remains unclear exactly which women with BRCA1/2 mutations stand to benefit from these drastic measures. For example, it’s been estimated that about 65 percent of women born with a BRCA1 mutation will develop invasive breast cancer over the course of their lives—which means approximately 35 percent will not. How can women in this situation be provided with more precise, individualized guidance on cancer prevention? An international team, led by NIH-funded researchers at the University of Pennsylvania, recently took an important first step towards answering that complex question.

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Creative Minds: Interpreting Your Genome

Artist's rendering of a doctor with a patient and a strand of DNA

Credit: Jane Ades, National Human Genome Research Institute, NIH

Just this year, we’ve reached the point where we can sequence an entire human genome for less than $1,000. That’s great news—and rather astounding, since the first human genome sequence (finished in 2003) cost an estimated $400,000,000!  Does that mean we’ll be able to use each person’s unique genetic blueprint to guide his or her health care from cradle to grave?  Maybe eventually, but it’s not quite as simple as it sounds.

Before we can use your genome to develop more personalized strategies for detecting, treating, and preventing disease, we need to be able to interpret the many variations that make your genome distinct from everybody else’s. While most of these variations are neither bad nor good, some raise the risk of particular diseases, and others serve to lower the risk. How do we figure out which is which?

Jay Shendure, an associate professor at the University of Washington in Seattle, has an audacious plan to figure this out, which is why he is among the 2013 recipients of the NIH Director’s Pioneer Award.

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Different Cancers Can Share Genetic Signatures

Cancer types floating over a cell with unraveling DNA

NIH-funded researchers analyzed the DNA of these cancers.

Cancer is a disease of the genome. It arises when genes involved in promoting or suppressing cell growth sustain mutations that disturb the normal stop and go signals.  There are more than 100 different types of cancer, most of which derive their names and current treatment based on their tissue of origin—breast, colon, or brain, for example. But because of advances in DNA sequencing and analysis, that soon may be about to change.

Using data generated through The Cancer Genome Atlas, NIH-funded researchers recently compared the genomic fingerprints of tumor samples from nearly 3,300 patients with 12 types of cancer: acute myeloid leukemia, bladder, brain (glioblastoma multiforme), breast, colon, endometrial, head and neck, kidney, lung (adenocarcinoma and squamous cell carcinoma), ovarian, and rectal. Confirming but greatly extending what smaller studies have shown, the researchers discovered that even when cancers originate from vastly different tissues, they can show similar features at the DNA level

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