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What is Cancer? Taxonomy 101

Sarcoma, carcinoma , leukemia, lymphoma. There are so many terms. What do they mean? ​


The medical jargon used to classify cancer can be overwhelming and confusing, but it doesn't have to be. Here is a basic summary of cancer taxonomy.

Cancer is classified based on the tissue type from which the cancer originated and the anatomical location or just the tissue type alone. Essentially, a tissue is a group of cells. For example, epithelial tissue is composed of cells that comprise the inner and outer layer of the body.


Carcinomas are cancers that have arisen from epithelial tissue that lines the inner and outer surfaces of the body. Carcinomas are further classified based on the type of epithelial cells of which they are composed as well as their primary anatomic site. For example, a squamous cell carcinoma of the base of tongue means the tumor originated at the base of the tongue, and histologically, the cells of the tumor are squamous cell (squamous cells are flat, thin epithelial cells). There are several types of carcinomas, but their commonality is that they derive from epithelial cells.


Sarcomas are cancers of connective tissues. Sarx in Greek means flesh. Examples of connective tissue includes cartilage, fat, muscle, blood, and bones. Sarcomas are often classified by the type of tissue they resemble. Liposarcomas, for example, resemble fat. Sarcomas do not include cancers of the blood, bone marrow (hematopoeitic mesenchymal cells) or lymphatic system.

Myeloid Tumors

Classifications of leukemias and lymphomas are complex. In essence, however, leukemias are blood cell tumors that develop in the bloodstream, while lymphomas are blood cell tumors that develop and mature in the lymphatic system. Lymphomas and leukemias are often colloquially called liquid tumors. They are further subdivided based on their cytology and histology.

Mixed Tumors

Sometimes tumors may be composed of mixed tissue types.

In addition to classifying the cancer by the cell type and/or anatomic origin, tumors are also described by stage and grade.

It is important to note this is just an overview and does not represent, replace or constitute medical advice. If you have questions about cancer or a cancer diagnosis, it is recommended that you ask a member of your oncology team.

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