Lymph nodes are small, bean-shaped structures that are part of the lymphatic system, which is a network of vessels and nodes that help to filter and remove waste and toxins from the body. Lymph nodes can be found throughout the body, including in the breast.The lymph nodes in the breast are located in the axilla, also known as the armpit. They are responsible for filtering lymph fluid that drains from the breast and surrounding areas. When a breast tumor is present, cancer cells may spread to these lymph nodes, which can indicate the progression of the disease.Lymph nodes in the breast can be evaluated for the presence of cancer by performing a procedure called a sentinel lymph node biopsy (SLNB). During this procedure, a small amount of radioactive material or blue dye is injected into the breast tissue. The dye or radioactive material then travels to the first lymph node(s) that it encounters, called sentinel node(s). The sentinel node(s) is then removed and evaluated for the presence of cancer cells. If cancer cells are found in the sentinel node(s), further evaluation and treatment may be necessary.It is important to note that the presence of cancer in the lymph nodes does not necessarily mean that the cancer has spread to other parts of the body. However, it can indicate a higher risk of recurrence or progression of the disease. Therefore, evaluating the lymph nodes is an important step in determining the stage of breast cancer and developing an appropriate treatment plan.In addition to SLNB, there are other methods to evaluate the lymph nodes in the breast such as ultrasound, CT, MRI and PET-CT. These imaging techniques can help to detect any abnormalities in the lymph nodes, but they are not always able to distinguish between benign and malignant changes.In conclusion, lymph nodes are an important part of the lymphatic system that are found throughout the body, including in the breast. They are responsible for filtering lymph fluid and can be evaluated for the presence of cancer through a procedure called a sentinel lymph node biopsy. The results of this procedure can help to determine the stage of breast cancer and develop an appropriate treatment plan. It is important to note that other imaging techniques such as ultrasound, CT, MRI and PET-CT are also used to evaluate the lymph nodes but are not always able to distinguish between benign and malignant changes.