Biopsy is a medical test that is done by surgically extracting samples of tissues for examination. Biopsy is done when other diagnostic tests like CT-scans and MRIs are unable to distinguish between cancerous and noncancerous cells. Biopsy is a procedure done by surgeons, or interventional radiologists. The extracted tissues are examined under microscopes and analyzed chemically by pathologists in order to ascertain the cause of disease. In some cases, biopsies are done after the performance of surgeries. When the diseased parts are removed with surgeries and sent for biopsy for further investigations, they are called excisional biopsies. When biopsies are done by just extracting samples of the tissue or skin without removing the entire diseased part, then it is called incisional biopsy. There are other types of biopsies like endoscopic biopsy, liquid biopsy, needle aspiration biopsy, and others that have lesser risks and are not very invasive. Biopsies are done to evaluate cancer.