Young women can and do get breast cancer. While breast cancer in young women accounts for a small percentage of all breast cancer cases, the impact of this disease is widespread. Breast cancer is the leading cause of cancer death in women ages 15 to 54. There are more than 250,000 women living in the U.S. who were diagnosed with breast cancer at the age of 40 or under, and approximately 10,000 young women will be diagnosed in the next year.