• Question: Why does cancer exist?

    Asked by ChaiLatte to David, Eva, Kate, Nicholas, Rachel on 9 Nov 2015.
    • Photo: Kate Wright

      Kate Wright answered on 9 Nov 2015:

      I’m not a biologist, so don’t take my word for this, but I think cancer comes about when DNA gets damaged. DNA controls what your cells do and if it gets damaged then when the cells replicate (make copies of themselves), they can go way overboard and just keep replicating and replicating until it forms a tumour. This actually happens all the time and the body is really good at spotting these dodgy cells and destroying them before it turns into cancer, but sadly it doesn’t always manage it…

    • Photo: Rachel McMullan

      Rachel McMullan answered on 9 Nov 2015:

      Cancer isn’t just one disease. There are lots of different types and lots of different causes but all cancers are made of cells that are dividing uncontrollably to form a tumour. Cells have to divide to heal wounds and replace old cells so cell division is really important. Cell division in cancer is different because it is out of control so it happens in the wrong place and at the wrong time.

    • Photo: Nicholas Pearce

      Nicholas Pearce answered on 11 Nov 2015:

      Hey,

      DNA is a really big and complicated substance. Because it is so big, it’s easy for little things to go wrong with it: a chemical could react with the DNA and lip inside, oxygen could damage it, even the energy from a bit of sunlight can change DNA slightly.
      Our body is good at repairing DNA when this happens, but it isn’t perfect, and these little changes start to add up. If too many changes happen to the DNA, cancers can form and the body can no longer repair the damage.
      So cancer exists because we can’t stop and fix all the little changes to DNA that happen over time. This can happen to most creatures too – even dinosaurs could have got cancer.

    • Photo: David Nunan

      David Nunan answered on 11 Nov 2015:

      I wish it didn’t as I see a lot of suffering with this in my job. One good thing is there are lots of scientists working hard to find a cure and also to help people live better with cancer.

      Cancer is caused by a mutation in the DNA of certain cells that causes them to replicate at an increased rate. When this happens in an organ, like the liver for example, these cancer cells start to compete with the healthy liver cells for nutrients and other things that help them regenerate. Unfortunately the cancer cells kind of “beat up” the healthy cells and usually win the fight! It means that the liver stops being able to work properly and that is what actually causes you to become sick.

      The mutations in the DNA can occur because of genetic factors but also from environmental ones. Smoking is a good (bad) example of an environmental risk factor for causing cancer.

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