Your doctor may remove a piece of tumor tissue to study it in the laboratory. Tumor tissue testing will confirm if a tumor is cancerous and can identify treatments that are most likely to help treat the cancer.
Before you undergo a tumor tissue test, consider learning about NET tissue donation and how your tissue may help researchers develop laboratory models of NETs. NETRF works with Pattern.org to collect excess tissue for research into the causes and treatments of NETs. This excess tissue is a very small amount and does not affect your diagnosis or tumor typing.
During a biopsy a physician removes cells or tissues for testing. The method used to do a biopsy depends on the location of the tumor.
Endoscopic ultrasound-guided fine-needle aspirations (EUS-FNA) involves taking a sample of tissue to examine it under a microscope. An endoscope is a thin, tube-like instrument with a light and a lens and a biopsy needle at the end. An integrated ultrasound probe bounces high-energy sound waves off internal organs and tissues to create a picture on a monitor. This picture helps the doctor see the location where the biopsy needle is to be placed.
Fine-needle aspiration (FNA) is a biopsy of the lung that involves removing tissue or fluid with a thin needle. A CT scan, ultrasound, or other imaging procedure first finds abnormal tissues or fluid in the lung. A small incision is then made in the skin and the biopsy needle is inserted into the abnormal tissue or fluid. A sample is then removed with the needle and sent to a laboratory where a pathologist will view the sample under a microscope to look for cancer cells. A chest x-ray is done after the procedure to make sure no air is leaking from the lung into the chest.
Immunohistochemistry (IHC) uses antibodies to check for specific antigens in a tissue sample. The antibody is usually linked to a radioactive substance or a dye that causes the tissue to brighten under a microscope. This type of test may be used to tell the difference between the types of cancer. Typically, pathologists will test tumor tissue for chromogranin A and synaptophysin, among other markers.