This is a medical question of type : exams and tests 
 How to diagnose Breast Cancer ? 
 Tests that examine the breasts are used to detect (find) and diagnose breast cancer.
                    Check with your doctor if you notice any changes in your breasts. The following tests and procedures may be used:         -   Physical exam and history : An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patients health habits and past illnesses and treatments will also be taken.     -   Clinical breast exam (CBE): An exam of the breast by a doctor or other health professional. The doctor will carefully feel the breasts and under the arms for lumps or anything else that seems unusual.    -  Mammogram: An x-ray of the breast.     -   Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. The picture can be printed to be looked at later.    -    MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of both breasts. This procedure is also called nuclear magnetic resonance imaging (NMRI).    -   Blood chemistry studies : A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease.     -   Biopsy : The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. If a lump in the breast is found, a biopsy may be done.  There are four types of biopsy used to check for breast cancer:               -  Excisional biopsy : The removal of an entire lump of tissue.       -  Incisional biopsy : The removal of part of a lump or a sample of tissue.       -  Core biopsy : The removal of tissue using a wide needle.       -  Fine-needle aspiration (FNA) biopsy : The removal of tissue or fluid, using a thin needle.
                
                
                    If cancer is found, tests are done to study the cancer cells.
                    Decisions about the best treatment are based on the results of these tests. The tests give information about:         - how quickly the cancer may grow.    - how likely it is that the cancer will spread through the body.    - how well certain treatments might work.    - how likely the cancer is to recur (come back).        Tests include the following:         -   Estrogen and progesterone receptor test : A test to measure the amount of estrogen and progesterone (hormones) receptors in cancer tissue. If there are more estrogen and progesterone receptors than normal, the cancer is called estrogen and/or progesterone receptor positive. This type of breast cancer may grow more quickly. The test results show whether treatment to block estrogen and progesterone may stop the cancer from growing.    -   Human epidermal growth factor type 2 receptor (HER2/neu) test : A laboratory test to measure how many HER2/neu genes there are and how much HER2/neu protein is made in a sample of tissue. If there are more HER2/neu genes or higher levels of HER2/neu protein than normal, the cancer is called HER2/neu positive. This type of breast cancer may grow more quickly and is more likely to spread to other parts of the body. The cancer may be treated with drugs that target the HER2/neu protein, such as trastuzumab and pertuzumab.    -  Multigene tests: Tests in which samples of tissue are studied to look at the activity of many genes at the same time. These tests may help predict whether cancer will spread to other parts of the body or recur (come back). There are many types of multigene tests. The following multigene tests have been studied in clinical trials:               -  Oncotype DX : This test helps predict whether stage I or stage II breast cancer that is estrogen receptor positive and node negative will spread to other parts of the body. If the risk that the cancer will spread is high, chemotherapy may be given to lower the risk.      -  MammaPrint : This test helps predict whether stage I or stage II breast cancer that is node negative will spread to other parts of the body. If the risk that the cancer will spread is high, chemotherapy may be given to lower the risk.                 Based on these tests, breast cancer is described as one of the following types:         -  Hormone receptor positive (estrogen and/or progesterone receptor positive) or hormone receptor negative (estrogen and/or progesterone receptor negative).    - HER2/neu positive or HER2/neu negative.    -  Triple negative (estrogen receptor, progesterone receptor, and HER2/neu negative).         This information helps the doctor decide which treatments will work best for your cancer.