• Question: Why can we not find a cure to cancer the same way we find one for other diseases?

    Asked by NotSally to Ceri, Marikka, Matt, Rob, Sally on 18 Nov 2014.
    • Photo: Sally Cutler

      Sally Cutler answered on 18 Nov 2014:

      Hi, I hope so. Cancer can arise from different sources and so it may be that some can be managed whilst others not. Indeed infections can promote some forms of cancer.

    • Photo: Ceri Dare

      Ceri Dare answered on 18 Nov 2014:

      Many sorts of cancer can now be effectively treated and cured. However cancer is not just one disease, it is lots of different sorts of illnesses. So we have to work on each type of cancer one at a time, which takes a long time.

    • Photo: Marikka Beecroft

      Marikka Beecroft answered on 19 Nov 2014:

      Cancer is caused when your own cells start to multiply out of control, whilst other diseases are caused by microbes, proteins or genetics. The tricky thing about treating cancer is that a cancer cell is a part of you and your body can’t tell the difference between a cancer cell and a healthy cell so doesn’t attack it. Treatments for cancer means also means that they are going to kill healthy cells as well so it’s a balance of trying to get rid of cancer cells and doing harm to your body. That means a lot of effort, time and consideration needs to be taken to make sure treatments are going to make you healthy not more sick.

    • Photo: Robert Hampson

      Robert Hampson answered on 19 Nov 2014:

      The techniques we use to develop drugs for cancer are broadly the same as with other diseases. Many types of cancer can be effectively treated and cured but there are many different types. There are also many other diseases we have not cured.

      Cancer is quite a challenging disease for many reasons. The first reason is that there are many different types of cancer. They appear in different locations, with different characteristics, and they need different treatments. In this way, cancer is not like curing one disease, it is more like curing hundreds. Also, this makes it difficult for doctors as they need to know what kind of cancer you have before they can give you the right treatment.

      Secondly, cancer cells are essentially human cells gone wrong. Whereas bacteria and even fungi are fairly different to human cells. Cancer cells are essentially the same, it is very hard to find a target that will kill cancer cells without killing human cells.

      Finally, most non infectious diseases are caused by one or two simple mechanisms. However, cancer is caused by a minimum of 4-6. Most cancers require several of the “Six hallmarks of cancer” to cause a disease (The “Six hallmarks of cancer” is a fairly important paper from the year 2000 published in the scientific journal Cell by Hanahan ad Weinberg).

      The six hallmarks are:
      1)Producing their own growth signals
      2)Being resistant to anti-growth signals
      3) Evading cellular programmes for suicide (these programmes are there to terminate cells which start to go wrong)
      4) they must be able to reproduce without limit (most reproduction is eventually stopped by the cells “old age” mechanism called senescence)
      5) they must be able to generate blood vessels
      6) they can be able to invade tissues and produce tumours elsewhere

      Whereas with the normal simple diseases, you can develop drugs to target the mechanism. This is not really possible with cancer as you would have to develop a drug for each mechanism. There also many different ways that cancers produce each of the six hallmarks, so we may need to produce more than one drug per hallmark. Basically, because cancer is so complex, our only option is to try and kill the cells which is difficult, as I mentioned before.

      Hopefully that helps you understand why cancer is difficult to treat!

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