Breast cancer is a disease that forms from cancerous cells in the breast, most commonly found in the lobules. Around 12% of women will develop invasive breast cancer in their lifetime. Risk factors include family history, reproductive history, alcohol consumption, old age, race/ethnicity, and diet and exercise. Mutated BRCA1 and BRCA2 genes can also play a role in breast cancer development. Symptoms may include breast lumps, nipple discharge, skin changes, and breast shape changes. Treatment options include surgery such as lumpectomy or mastectomy, chemotherapy, and radiotherapy. Breast cancer remains a leading cause of cancer death in women.