For this reason in situ cancers are sometimes called precancerous, meaning they may develop into invasive cancers at some later time. This percentage is increasing because breast cancers found on mammograms are often in situ. The other breast cancers are all invasive cancers. Invasive cancers have broken out of the boundaries of the group of cells they came from and are invading or growing into the nearby breast tissue. The second part of the name tells something about that particular kind of cancer.
Some breast cancers get their names from the cells of the breast that turned into cancer.
Eighty persent of breast cancers are ductal. If a cancer arises from the part of the breast that produces milk, it is called a lobular cancer. Ten percent of breast cancers are lobular. Normal cells in our bodies have a predetermined life span, They grow, they give rise to new cells and they die. Our bodies continually replace dead cells with new ones.