How Cancers Are Named: A Simple Guide

This page is for anyone trying to make sense of a cancer name, whether on a pathology report, a patient portal or a care team's notes. It explains the pattern behind the names and why the details matter.

There are more than 100 types of cancer. NCI says they are usually named for the organ or tissue where the cancer forms. Lung cancer starts in the lung. Brain cancer starts in the brain.

Names often go one step further and say which type of cell the cancer formed from. NCI gives epithelial cells and squamous cells as examples. Once you know the pattern, a long name like "invasive ductal carcinoma" is easier to read.

NCI describes several main groups of cancers that begin in specific types of cells.

• Carcinoma. NCI calls carcinomas the most common type of cancer. They form from epithelial cells, which cover the inside and outside surfaces of the body. Carcinomas that begin in different epithelial cells have more specific names. Adenocarcinoma forms in epithelial cells that make fluids or mucus. Squamous cell carcinoma forms in flat squamous cells. Basal cell carcinoma begins in the lower layer of the skin's outer surface.
• Sarcoma. Sarcomas form in bone and soft tissues, including muscle, fat, blood vessels, lymph vessels, and fibrous tissue such as tendons.
• Leukemia. Leukemias begin in the blood-forming tissue of the bone marrow. NCI says they do not form solid tumors. Abnormal white blood cells build up in the blood and bone marrow instead.
• Lymphoma. Lymphoma begins in lymphocytes, which are disease-fighting white blood cells that are part of the immune system. The two main types are Hodgkin lymphoma and non-Hodgkin lymphoma.
• Multiple myeloma and melanoma. Myeloma begins in plasma cells, another type of immune cell. Melanoma begins in cells that become melanocytes, which make the pigment that gives skin its color.

NCI also notes that brain and spinal cord tumors are named for the type of cell they formed from and where in the central nervous system they first formed.

Many names combine a cell type with a place. NCI describes ductal carcinoma as the most common type of breast cancer. It begins in the lining of the milk ducts. The name tells you the cell type, carcinoma, and the place, the ducts.

A name can narrow things down further. NCI says non-small cell lung cancer is a group of lung cancers named for the kinds of cells in the cancer and how the cells look under a microscope. Its three main types are adenocarcinoma, squamous cell carcinoma and large cell carcinoma.

Some names come from tests on the cells. NCI says triple-negative breast cancer means the tumor cells do not have estrogen receptors, progesterone receptors, or large amounts of HER2/neu protein. NCI describes biomarker testing as a lab method that checks tissue, blood, or other body fluid for certain genes, proteins, or other molecules. It says the testing may help diagnose some cancers and plan treatment.

A cancer keeps the name of where it began, even after it spreads. NCI says metastatic cancer has the same name and the same type of cancer cells as the original, or primary, cancer. Breast cancer that forms a metastatic tumor in the lung is metastatic breast cancer, not lung cancer.

A cancer is named for where it started, not where it spreads.

A pathologist is a doctor who studies cells and tissue under a microscope. NCI says the pathology report gives the definitive cancer diagnosis, and its diagnosis section names the cancer type. It also gives the tumor grade, lymph node status, margin status and stage.

NCI lists several common words on these reports, such as carcinoma, adenocarcinoma, invasive, in situ, benign, malignant and neoplasm. Our pages on adenocarcinoma, squamous cell, neoplasm and how to read a pathology report explain them one at a time. For the carcinoma and sarcoma groups side by side, see carcinoma versus sarcoma.

NCI says that for cancer, knowing the cell type is important to diagnose the cancer, plan treatment, and work out the outlook. So the full name on your report is worth understanding. Ask your care team to explain every part of it.

• National Cancer Institute: What Is Cancer?
• National Cancer Institute: Pathology Reports
• National Cancer Institute: Dictionary of Cancer Terms
• National Cancer Institute: Metastatic Cancer: When Cancer Spreads