Stem Cells: the root of cancer?

‘Cancer is indeed a disease of stem cells’, according to Dr Brian Huntly, MRC Senior Clinical Research Fellow at Cambridge University. I, for one, had always associated stem cells with treatments and promising cures. It therefore came as a huge surprise to me when I sat through an hour of PowerPoint slides proposing a possibility that cancer was the result of the abnormal behaviour of stem cells.

In a talk involving Dr Kat Arney, Dr Matt Smalley and Dr Brian Huntly, they discussed the prevalence of different cancers, cancer recession, and how and why stem cells play a critical role in cancer pathology. According to Dr Matt Smalley, cells undergo genetic changes, also known as mutations, quite commonly; however, unrepaired genetic changes are fairly rare. This is because it requires about 6–10 unrepaired genetic lesions in order to prompt a normal cell to turn into a cancer cell. The probability of this occurring is fairly low, simply because most of our cells do not live long enough to sustain that many genetic changes.

Stem cells and some intermediate cells, on the other hand, have the ability to self-renew and usually live long enough to accumulate enough mutations that put them at risk of adopting abnormal behaviour that could become cancerous. Thus understanding stem cells would help us understand the origins of cancer. This knowledge in turn can be used to deduce what causes different tumour types and improve treatment. Huntly emphasised that the aim should be for researchers to discover more about normal stem cells and superimpose them on cancer stem cells, in order to deduce significant differences between the two that may induce one type to adopt abnormal behaviour, and the other to differentiate or self-renew normally.

Now before you all start identifying stem cells as a villain of some sort, I want to emphasise Dr Huntly’s point that although the cancer stem cell hypothesis is supported by evidence from Leukaemia cases, the hypothesis applies to specific cancers – melanomas for example, have nothing to do with stem cells at all. The implication of the cancer stem cell hypothesis would prompt a shift in cancer treatment from killing dividing cells regardless of their properties, to therapies that block behaviour and are aimed at prevention rather than targeting the identity of the cell.

This talk, not only being very interesting and enlightening, also proved more than accessible to the layperson. Not being of a biomedical background, I was delighted to have been able to understand the cancer stem cell hypothesis. It was a wonderful start to the Cheltenham Science Festival and I look forward to attending more talks like it, in particular those by our own researchers at UCL.