Our bodies are made up of billions of cells. The cells are so small that they can only be seen under a microscope. These cells are grouped together to make up the tissues and organs of our bodies. These cells are basically the same, but they vary in some ways. This is because the body organs do very different things.
For example, nerves and muscles do very different things. So nerve and muscle cells have different structures.
Cancers can be grouped according to the type of cell they start in. There are 5 main categories
- Carcinoma – cancer that begins in the skin or in tissues that line or cover internal organs. There are a number of subtypes, including adenocarcinoma, basal cell carcinoma, squamous cell carcinoma, and transitional cell carcinoma
- Sarcoma – cancer that begins in the connective or supportive tissues such as bone, cartilage, fat, muscle, or blood vessels
- Leukaemia – cancer that starts in blood forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and go into the blood
- Lymphoma and myeloma – cancers that begin in the cells of the immune system
- Brain and spinal cord cancers – these are known as central nervous system cancers
Cancers can also be classified according to where they start in the body, such as breast cancer or lung cancer.