Breast Cancer Is 10 Diseases Says Landmark Study
Breast cancer is at least 10 different diseases, each with its own genetic signature and pattern of weak spots, according to a new landmark study that promises to revolutionize diagnosis and prognosis, and pave the way for individualized, tailored treatment.
The study group, METABRIC (Molecular Taxonomy of Breast Cancer International Consortium), reports its findings in the 18 April online issue of Nature.
The Cancer Research UK-funded study is the largest global gene study of breast cancer tissue ever conducted, involving a large team of researchers, primarily in the UK and Canada.
Led by Professor Carlos Caldas from Cancer Research UK’s Cambridge Research Institute and Professor Sam Aparicio from the British Columbia Cancer Centre in Canada, the team uncovered crucial new information about breast cancer.
The researchers analyzed the DNA and RNA of breast tumor samples from nearly 2,000 women who had been diagnosed between five and 10 years ago, and for whom information about the tumor characteristics had been meticulously recorded.
They compared this with the women’s survival, and other information, like their age at diagnosis.
Breast Cancer Statistics
Aside from non-melanoma skin cancer, breast cancer is the most common cancer among women in the United States. It is also one of the leading causes of cancer death among women of all races and Hispanic origin populations.
In 2007 (the most recent year numbers are available) -
202,964 women were diagnosed with breast cancer.
40,598 women died from breast cancer.
*Incidence counts cover approximately 99% of the U.S. population. Death counts cover 100% of the U.S. population. Use caution in comparing incidence and death counts.
†Source: U.S. Cancer Statistics Working Group. United States Cancer Statistics: 1999–2007 Incidence and Mortality Web-based Report.
Because the study was able to look at many tumors with rich data on each, it identified new patterns and “clusters” in the data not spotted before.
In the study, the team classified breast cancer into at least 10 different subtypes: each characterized by common genetic features that link to survival.
This suggests we need to rethink what we call breast cancer and start looking at it as at least 10 different diseases, each with its own molecular fingerprint and pattern of weak spots.
Dr Harpal Kumar, chief executive of Cancer Research UK, told the press the study will completely change the way we look at breast cancer.
Breast Cancer in the United States: 2011
The National Breast Cancer Coalition (NBCC) is a grassroots organization dedicated to ending breast cancer through action and advocacy. NBCC members are committed to reaching this goal by 2020. Following are a few statistics that speak to the need to end this deadly disease:
- The National Cancer Institute estimates that a woman in the United States has a 1 in 8 chance of developing invasive breast cancer during her lifetime. This risk was about 1 in 11 in 1975 (ACS, 2010).
- On January 1, 2008, in the United States there were approximately 2,632,005 women alive who had a history of breast cancer (SEER, 2011).
- Breast cancer is the second leading cause of cancer death for women in the U.S, after lung cancer. Approximately 39,970 women and 450 men in the U.S. will die from the disease in 2011 (ACS, 2011).
- Excluding skin cancer, breast cancer is the most commonly diagnosed cancer among women in the United States. It is estimated that 230,480 new cases of invasive breast cancer will be diagnosed among women in the U.S. in 2011. In addition to invasive cancers, 57,650 new cases of in situ breast cancer will be diagnosed; approximately 49,003 of which will be ductal carcinoma in situ (DCIS). Approximately 2,140 new cases of invasive breast cancer will be diagnosed among U.S men (ACS, 2011).
- The incidence of breast cancer declined from 1999 to 2003, with the greatest decline among white women. Incidence rates have remained relatively stable since 2003 (SEER, 2011).
- According to the SEER data from 2001-2007, approximately 90% of women diagnosed with invasive breast cancer were still living five years after getting the disease; among black women, approximately 77% were still living five years after getting the disease (SEER, 2011).
- Older women are much more likely to get breast cancer than younger women. From 2004-2008, the median age for a breast cancer diagnosis was 61 years of age. Approximately 0.0% were diagnosed under age 20; 1.9% between 20 and 34; 10.2% between 35 and 44; 22.6% between 45 and 54; 24.4% between 55 and 64; 19.7% between 65 and 74; 15.5% between 75 and 84; and 5.6% 85+ years of age. (SEER, 2011).
Caldas, who is also Professor of Cancer Medicine at Cambridge’s Department of Oncology, said “breast cancer” should be regarded as an umbrella term for a range of diseases.
The findings could change the way drugs are tailored to treat individual women with breast cancer.
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.
The study also reveals the relationship between these breast cancer genes and known signalling 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.
Over decades, the METABRIC project has produced a “goldmine” of data, says Caldas.
The process is not unlike that of cartography. At first, intrepid explorers discover new continents, defined by outlines and some rough impressions of terrains and landscapes.