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MedlinePlus is an online health information resource for patients and their families and friends. It is a service of the National Library of Medicine (NLM), the world's largest medical library, which is part of the National Institutes of Health (NIH). Learn more about MedlinePlus
- FEATURED TOPIC
- Breast Cancer
- Breast cancer is a cancer that starts in the breast tissue, when cells change and grow out of control. These extra cells can form a mass called a tumor.
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