Colon Carcinoma: Screening by blood test

18. April 2013
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It's still true that colorectal cancer screening by blood test is a thing of the future. However researchers have discovered markers whose use makes such an implementation a possibility.

Early cancer screening is an important tool. Those who are insured are entitled to the benefits of these provisions – but too few use them. Colonoscopy, which is carried out as a statutory provision procedure from the age of 55 on and may be repeated after ten years, is only used by around 20 per cent of German citizens who are entitled to it. If it were possible to do colorectal cancer screening via a blood test, the participation rate would probably look different. Science fiction? True. However after their recent discoveries scientists at the Charité and the Max Planck Institute for Molecular Genetics in Berlin have this possibility in mind.

Molecular markers for colorectal cancer discovered

“How was it possible, using mouse models for colon cancer, for a preserved pattern involving around 13,000 identify epigenetic changes to be identified, in which cancer cells differ from healthy cells? The alterations have already been observed in very young mice in which the APC gene, a tumor suppressor, is defective”, says Dr. Markus Morkel, leader of the study. This means that these mutations brought about the epigenetic changes. These alterations do not necessarily have a functional role in the progression of cancer, but the researchers found that a large proportion of these changes are also shown to be present in human colon cancer tissue. These patterns consequently appear to be highly conserved during evolution, which is something important for a marker.

Recognition before the cancer develops?

Armed with this set of markers for cancer cells, the scientists under Dr. Morkel proceed in their search for clues in the blood. Since tumour cells not only divide uncontrollably but also go into uncontrolled apoptosis, there is quite a lot of free tumour DNA in the blood. Therefore epigenetic alterations in the form of attached methyl groups can also be found there. As the next step on the path to a simpler test option, what now needs to be proven is whether DNA and epigenetic changes are detectable in the blood of cancer patients.

Then the scientists will test whether positive detection capability can be gradually shifted to an ever earlier point in time. Since epigenetic changes with cancer are already triggered by a causal mutation in the APC gene, a gene of the Wnt/ Beta-catenin signal transduction pathway, the alteration would therefore need to be detected at an early stage at which the pre-cancerous tissue could still simply be removed from the intestine – making it an important prerequisite for very useful screening work.

Epigenetics and cancer – a promising combination

Epigenetic patterns are being researched with other cancers as well. In gastric cancer, patterns in tumours and cell lines can be found which allow differentiation of aggressive from less aggressive variants. In addition, scientists are trying to use epigenetic processes in anti-cancer therapies. In breast, liver and kidney cancer an enzyme from the histone deacetyltransferase group, HDAC11, undergoes the epigenetic changes. In healthy tissue however, the enzyme seems to play no important role. Therefore, researchers at the German Cancer Research Center in Heidelberg hope that by using the targeted suppression of HDAC11 cancer cells can be switched off selectively, something which has in cell culture experiments already worked.

Whether it be methods for early diagnosis of cancer, or for therapy – there seems to exist great potential in epigenetics. We can look forward to seeing what trends will emerge in the coming years.

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3 comments:

Maybe there is a suspicious region also in nr 4, but I dont understand why the terminal ileum …?

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Im a little angry about the pictures: in the first picture you have titled carcinoma 1, carcinoma 2, and a little polyp. What about the polyp beneath carcinoma 2, which is much larger that the small one? And the fact that carcinoma 2 is cut in 2 parts, one above, the other half on the other side.
Picture No 4 (small) has nothing to do with colon cancer!!! It seems to be the most part of the colon, but including terminal ileum, probably with M. Crohn, when you consider the restricted lenght. Sorry.

#2 |
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I am absolutely convinced that – however you did it, when seen from a superficial point of view, in a very professionel way, most readers don’t understand what your central message could be.It creates an impression “Wow what an elaborated article”! When your working place is munich, why do you think that this is the right language? When your main intention ist to reach only scientologists, well, maybe you have scelt the right way, but when you would rather write for all the busy working doctors of medicine in their studios, I don’t believe that there is someone to create a good german summary of your article.
Reading your article I initially not even understood if you mean tumor markers or genetical tests. What about polyposis, hereditary risks without polyposis, brca- mutation? What about the possibility for patients with high familiar risks to be examinated, tested and consulted in the ca. 14 universitary institutes oh human genetics in Germany?
I don’t understand your intention, sorry.

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