• Question: Why can't white blood cells engulf old produce antibodies to kill the cancer cells?

    Asked by to Amar, Andrea, Leah, Matt on 19 Mar 2014. This question was also asked by .
    • Photo: Andrea Hanvey

      Andrea Hanvey answered on 19 Mar 2014:

      Cancer cells are still our own cells. They are just cells that have lost control of cell division through mutations in genes that control cell division, programmed cell death or DNA repair. cells infected with a virus activate a protein marker on the outside of the cell membrane. this is recognised by some white blood cells which signals to them the cell is infected and needs to be engulfed or for antibodies to be made against the infecting virus. cancer is very sneaky, when the cell loses control no markers are put on the outside of the tumour cells. so the white blood cells don’t recognise the cells as being cancerous and in need of being destroyed.

      However Natural killer cells , a typeof white blood cell, do play a role in tumour surveillance, they can induce death in a tumour cell. some cancers evade detection by natural killer cells by removing certain cell markers.

      If we produce antibodies against our own cells its known as a autoimmune disorder, so your body attacks its self. cancer cells do not evoke this response in the body as its a different disease pathway

    • Photo: Matthew Lam

      Matthew Lam answered on 19 Mar 2014:

      Cancer cells are cells of your own body, so unlike a foreign cell (such as bacteria) your immune system doesn’t really see anything out of place and so doesn’t try to attack the cancer cells.

      There are new vaccine style therapies for cancer that are being developed which try to force the immune system to recognise charateristics which are only shown by cancer cells. This could help the immune system recognise cancer cells and attack/kill the cells.

    • Photo: Leah Fitzsimmons

      Leah Fitzsimmons answered on 19 Mar 2014:

      When a cell in your body initially becomes faulty other cells do usually spot this and prompt the cell to die. Dead and dying cancer cells are engulfed by white blood cells, but because these faulty cells are from your own body the immune system doesn’t recognise them as foreign, and so they don’t make antibodies against them.

      Once one faulty cell manages to escape being killed and engulfed and starts to grow, then it can start to form a tumour. Cells within tumours are also engulfed when they die and once the cells become more abnormal the white blood cells can start to recognise this and try to fight it (partly by making tumour-specific antibodies). Although the immune system does try to fight the cancer it is still not very efficient because the cancer cells still look a lot like your healthy cells and antibodies that recognised all of your cells and not just the cancer cells could kill you. This is why the immune system can’t usually kill a tumour.

      There are lots of researchers using antibodies to make cancer treatments, to enable your white blood cells to find and kill cancer cells more efficiently, but as I said, the difficult part is making antibodies that only bind to cancer cells.

      Cancer cells are also often found to have mutations that stop the cells being found by white blood cells and help them evade killing by the immune system, which makes it even harder for you immune system to fight back.

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