What is "breast cancer"?

What is "breast cancer"?

Breast cancer is cancer that starts in the breast, and it is where normal healthy tissues initially start to become hyperplastic, so they start to grow. There can also be genetic abnormalities and mutations that occur in the healthy cells, which cause them to start to become a little atypical. Once they become atypical, they start to grow faster, there are more genetic mutations, and they turn into a full-blown cancer. At that point, the breast cancer is usually an "in situ" cancer, meaning it is just there, within the breast. It has not invaded through the basement membrane, which is the lining of the normal, healthy cells. Once it becomes invasive cancer, it invades through that basement membrane, and spreads throughout the breast. It can then spread to lymph nodes and then spread to other organs and become metastatic.