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Our bodies are made of millions of cells which normally receive signals from genes which contain DNA. This controls when they grow and divide. If a cell is damaged or old it gets a signal to stop working, and dies.

Sometimes a change happens in a gene when the cells divide - this is called a mutation and can happen by chance. Some mutations mean the cell no longer understands instructions and may continue making more and more abnormal cells.

The cells begin to grow and reproduce in an uncontrollable way. These cells can then clump together to form a lump called a tumour, invading and destroying healthy tissue, including organs.

Cancer sometimes begins in one part of the body before spreading to other parts. This process is known as metastasis.

Types of cancer

The most accurate forecast to date from Cancer Research UK is that 1 in 2 people will develop cancer during their lifetime. There are more than 200 different types of cancer. Most are described by the area of the body they start in, for instance breast or lung cancer. Cancers can also be divided into groups according to the type of cell the cancer started from.


Carcinomas are cancers that start in the epithelial cells which cover the outside of our bodies as skin and also line or cover our internal organs. The most common carcinomas cancers that we hear talked about are:

  • Lung
  • Colorectal (bowel)
  • Prostate
  • Breast
  • Melanoma (skin)


Cancers that start in connective tissue are called sarcomas. They can be split into 2 main types, bone and soft tissue. They are rare, only around 1% of cancers diagnosed every year will be a sarcoma.


Cancers that start in the blood or bone marrow where bloods cells are made are called Leukaemia. They are another uncommon cancer making up only 3% of all cancer cases, but our awareness maybe greater as they are the most common cancers in children.

Other cancer types

  • Cancers that start in a plasma call is called myeloma
  • Cancers that start from cells in the lymphatic system, which is your body’s drainage system are called lymphomas
  • Cancers can also develop from other types of cell which include, brain tumours, neuroendocrine tumours and germ cell cancers

Different stages of cancer

When someone receives a cancer diagnosis it will often be classified by what stage the disease is at. Doctors will carry out tests to check how big the cancer is and whether it has spread into surrounding tissues. The stage of a cancer describes the size of a tumour and how far it has spread from where it started.

The earlier a cancer is diagnosed, generally the lower the stage, and the better the outcome for the person. Like any other disease - catching it early is key. This is why it’s important to see your GP as soon as you’re worried about a sign or symptom of cancer.

Staging and grading the cancer will allow the doctors to determine its size, whether it has spread and the best treatment options. As a simple rule, the lower the stage (such as a stages 0, 1 or 2),  the  smaller the cancer, and the less it has spread. A higher number (such as a stage 3 or 4) means the cancer is larger and may have spread to other areas.

It is the same with grading the cancer – generally the lower the grade the slower growing the cancer and the higher the grade the faster growing the cancer.

The stage and grade of your cancer will help the doctor decide on the best treatment for you.

If you or someone you love has been affected by cancer, our free Support Line is there for you. Just call 0808 808 1010