Study unpicks gene changes behind breast cancer
While his team don’t fully understand the process behind these storms, they think it may be down to components of the cell whose normal function is to edit, or mutate, DNA.
“What we believe…is that sometimes in normal cells…this stops functioning properly and over-functions. It causes too many mutations and the accumulation of those mutations pushes the cell along the line to become cancer.”
The team found that these and other mutations accumulate in breast cells over many years, initially slowly, but picking up greater momentum as genetic damage builds up.
By the time the breast cancers are large enough to be diagnosed, they are made up of a number of genetically related families of cells, with one family dominating the cancer, Stratton explained.
What are the key statistics about breast cancer?
Breast cancer is the most common cancer among American women, except for skin cancers. About 1 in 8 (12%) women in the US will develop invasive breast cancer during their lifetime.
The American Cancer Society’s most recent estimates for breast cancer in the United States are for 2012:
- About 226,870 new cases of invasive breast cancer will be diagnosed in women.
- About 63,300 new cases of carcinoma in situ (CIS) will be diagnosed (CIS is non-invasive and is the earliest form of breast cancer).
- About 39,510 women will die from breast cancer
- After increasing for more than 2 decades, female breast cancer incidence rates decreased by about 2% per year from 1999 to 2005. This decrease was seen only in women aged 50 or older, and may be due at least in part to the decline in use of hormone therapy after menopause that occurred after the results of the Women’s Health Initiative were published in 2002. This study linked the use of hormone therapy to an increased risk of breast cancer and heart diseases.
Breast cancer is the second leading cause of cancer death in women, exceeded only by lung cancer. The chance that breast cancer will be responsible for a woman’s death is about 1 in 36 (about 3%). Death rates from breast cancer have been declining since about 1990, with larger decreases in women younger than 50. These decreases are believed to be the result of earlier detection through screening and increased awareness, as well as improved treatment.
Mark Walport, director of the Wellcome Trust which helped fund the work, said the results showed how scientists are starting to see the landscape of mutations in breast cancer “in something approaching its full complexity”.
“As this work continues, we can hope to understand how breast cancer develops and thus how it might be treated more effectively,” he said in a statement.
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By Kate Kelland
LONDON