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The cancer cell

Nurse and patients talking about cancer   

This page has information about cancer cells and how they are different from normal body cells. There is information about


The characteristics of normal cells

Normal body cells have a number of important characteristics. They can

  • Reproduce themselves exactly
  • Stop reproducing at the right time
  • Stick together in the right place
  • Self destruct if they are damaged
  • Become specialised or 'mature'

How cancer cells are different

Cancer cells are different to normal cells in several ways. They don't die if they move to another part of the body and

Cancer cells don't stop reproducing

Unlike normal cells, cancer cells do not stop reproducing after they have doubled 50 or 60 times. This means that a cancer cell will go on and on and on doubling. So one cell becomes 2, then 4, then 8, then 16....

Diagram showing how cancer cells keep on reproducing to form a tumour

The cancer cells may be able to stop themselves self destructing. Or they may self destruct more slowly than they reproduce, so that their numbers continue to increase. Eventually a tumour is formed that is made up of billions of copies of the original cancerous cell. Scientists describe cancer cells as being 'immortal'.

Cancer cells don't obey signals from other cells

Something in the cancer cells overrides the normal signalling system. This may be because the genes that tell the cell to reproduce keep on and on sending signals. Or because the genes that normally tell the cell to stop reproducing have been damaged or lost. So the cancer cell keeps on doubling, regardless of the damage the extra cells cause to the part of the body where the cancer is growing.

Cancer cells don't stick together

Cancer cells can lose the molecules on their surface that keep normal cells in the right place. So they can become detached from their neighbours.

Diagram showing a cancer cell which has lost its ability to stick to other cells

This partly explains how cancer cells spread to other parts of the body.

Cancer cells don't specialise, but stay immature

Unlike normal cells, cancer cells do not carry on maturing once they have been made. In fact, the cells in a cancer can become even less mature over time. With all the reproducing, it is not surprising that more of the genetic information in the cell can become lost. So the cells become more and more primitive and tend to reproduce more quickly and even more haphazardly.


Grade and cancer cells

You may hear your doctor talk about the 'grade' of your cancer. This means how well developed or mature the cells look under a microscope. The more the cancer cells look like a normal cell, the more they will behave like one

  • A low grade cancer cell looks more like a normal cell
  • A high grade cancer cell looks more abnormal and is less well developed than a normal cell

Doctors call this 'differentiation'. Cells can be well differentiated, moderately differentiated, or poorly differentiated. This is the same as low, medium or high grade. It is also called grades 1, 2, or 3, where grade 1 is low grade.

Although there are many different ways of talking about this, it all comes down to the same thing. A low grade cancer is likely to grow more slowly and be less likely to spread than a high grade one. Doctors cannot be certain exactly how the cells will behave. But grade is a useful indicator. Grade is one of the factors doctors use to decide on treatment for some types of cancer.

The grade of a cancer is different to the stage of a cancer. The 'stage' describes how big the cancer is and if it has spread or not.


More information on how cells and tissues grow

Look at our section about how cells and tissues grow for detailed information.

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Updated: 24 July 2013