The world's largest catalogue of human breast cells has revealed early cell changes in carriers of BRCA gene mutations, offering a potential target for breast cancer prevention.
Faulty BRCA1 or BRCA2 genes increase the risk of developing breast cancer. Some patients that carry the mutations opt to have preventive surgery to remove their breasts. The results of a study, led by researchers from the University of Cambridge, raise the possibility of avoiding this surgery by using existing immunotherapy drugs as an early intervention to prevent breast cancer developing in carriers of BRCA1 and BRCA2 gene mutations.
Senior author of the study, Professor Walid Khaled, from the department of pharmacology and Wellcome-MRC Cambridge Stem Cell Institute, said: 'We're very excited about this discovery, because it opens up potential for a preventative treatment other than surgery for carriers of BRCA breast cancer gene mutations… Drugs already exist that can overcome this block in immune cell function, but so far, they've only been approved for late-stage disease. No-one has really considered using them in a preventative way before.'
The scientists found that immune cells in breast tissue of healthy women carrying BRCA1 or BRCA2 gene mutations showed signs of a malfunction known as 'exhaustion'. This mechanism – usually found in late-stage cancers – suggests that immune cells do not clear out damaged breast cells, which can eventually develop into cancer.
Immunotherapy drugs help the immune system recognise and fight cancer, which can be administered on their own or alongside other treatments. The research team will next test these drugs on mice, which, if successful, could lead to a pilot clinical trial in women with BRCA gene mutations.
The discovery – published in Nature Genetics – was found when the research team created an expansive catalogue of breast cells from healthy human breast tissue samples provided by the charity Breast Cancer Now's tissue bank.
The scientists used single cell RNA-sequencing on over 800,000 cells to create the human breast cell atlas, which was assembled from 55 women that had undergone risk reduction breast surgery.
Dr Simon Vincent, director of research at Breast Cancer Now, added: 'The best weapon we could have against breast cancer is the ability to stop it occurring in the first place. This research… suggests that we could prevent some women with altered genes from developing the disease by using drugs currently approved for treatment in the late stages of breast cancer. While further research is needed and clinical trials in humans are yet to take place, these findings could be a significant step forward in our care and treatment of people whose genes mean they have an increased risk of developing breast cancer.'
The atlas is now available for other researchers to use and add to, and also contains information on other risk factors for breast cancer, such as body mass index, contraceptive use, alcohol consumption and menopausal status.
Sources and References
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A single-cell atlas enables mapping of homeostatic cellular shifts in the adult human breast
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'Exhausted' immune cells in healthy women could be target for breast cancer prevention
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Breast cancer drugs breakthrough for women with 'Jolie gene'
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Drugs breakthrough could help those with faulty gene avoid breast cancer surgery
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