Cancer is more common than you may think. In fact, it is estimated that nearly 1 out of every 3 people in the United States will battle a form of cancer at some point during their lives. Although more than 100 types of cancers exist worldwide, the most frequently detected in women is breast cancer. Of the 266,000 American women diagnosed each year, roughly 5-10% develop the disease as a result of inherited gene mutations, or changes. In other words, breast cancer can run in the family.