New treatment options for cancer patients may be developed following the discovery that incorrect signalling in intestinal stem cells can trigger the disease, writes Dick Ahlstrom
SCIENTISTS have tracked down a form of stem cell that can mutate to cause bowel cancers. The findings from two separate research groups are important because they could point the way towards quicker diagnosis and better treatments for this dangerous form of cancer.
The work is particularly significant for Ireland given that we have the third-highest per capita incidence of intestinal cancers in the world, according to figures from the Irish Cancer Society.
Each year almost 1,000 men and about 750 women develop colorectal cancers, 12.4 per cent and 10 per cent of cancers respectively. And there are about 925 deaths annually from this disease, about 15 per cent of all cancer deaths for men and for women, the Irish Cancer Society indicates.
More than three-quarters of all patients diagnosed with colorectal cancer undergo surgery for the disease, with patient outcome strongly linked to how quickly it is diagnosed and whether the cancer was able to spread into nearby tissues. The reason why the new findings are so significant is that they have the potential to deliver better ways to spot colorectal cancers early.
Two research papers working on slightly different but related parts of this research subject are published this morning in the journal, Nature. Both look at a particular "signalling pathway" for what are described as cancer stem cells. Cells communicate with one another and carry out their required functions due to signalling, a form of biochemical communication where genes are switched on and off in a controlled fashion.
Sometimes mutations can occur in the signalling, a factor that can lead to disease. The research groups, based in Tennessee in the US and in Utrecht in the Netherlands, were interested in the Wnt pathway, important because it is known to trigger intestinal cancer.
They focused on at a tiny piece of the Wnt pathway, a connecting point or receptor on the cell surface that is a marker for intestinal stem cells. The Dutch group found that when the Wnt pathway was switched on in cells that had this marker it caused tumour formation.
The US group also looked at this intestinal stem-cell marker. They found that these cells also have another surface marker called prominin-1 (Prom1) and when the Wnt pathway is abnormally activated cells showing the Prom1 marker also form intestinal tumours.
"Our data indicate that Prom1 marks stem cells in the adult small intestine that are susceptible to transformation into tumours," they report. Only a small fraction of the stem cells do this and they now hope to be able to answer a key question - whether these cancer-causing stem cells come directly from mutated stem cells or whether they are mature cells that change to something that looks like a stem cell during tumour formation.
The Dutch group believes their findings on the Wnt pathway and the cell marker "lend support to the cancer stem cell concept". Being able to see cells that have these important markers could lead to methods for earlier diagnosis of colorectal cancers.