Inflammation and cancer: one aspirin please!

Aspirin

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There have been some interesting studies recently that have suggested that taking an aspirin a day for five years reduced one’s risk of certain cancers (in this case it was colorectal and other solid cancers).  We have all heard the issue of older folks who take an aspirin a day to help prevent hear attacks or even a glass or red wine a night with similar properties, but cancer?  This seems rather odd.

Aspirin is known as a pain-killer but it is in the class of drugs known as non steroidal anti-inflammatory drugs or NSAIDs.  Thus, inherit in this drug are some anti-inflammatory properties.  In fact, it was when looking at people who were taking an aspirin a day to prevent heart disease, that researches started noticing that their cancer rates seemed lower.  Actually, it’s not that the rates of cancer are lower it’s that their incidence of death due to cancer was lower.  So, in a trial that looked at people who had taken aspirin for over 7 and 1/2 years that they had a 30 reduction in the 20-year risk of cancer for all solid cancers combined.  And they also had a 60% reduced risk for adenocarcinoma of the esophagus.   

Why is this?  How can an aspirin help prevent cancer.  Cancer and inflammation have been linked for many years.  However, as inflammation occurs regularly even in non cancer conditions (e.g. as normal responses to control infections) it has been a very difficult to study this in humans.  One of the more specific observation that was made by Dr. Dvork of Harvard University was that cancers share similar developmental processes or mechanisms and that tumors are indeed, “wounds that do not heal”.  In fact, it appears that chronic inflammation is part and parcel of almost all stages of cancer development from driving the initial genetic changes (mutations) to providing conditions that enable to cancer cell to migrate to another area (metastasize) and even preventing the anti-cancer immune response to take hold. 

There are a number of different genes and their protein products that regulate inflammation: too many to list here.  But, one of the hallmark set of proteins are the ones that belong to the NFKB pathways.  In fact, it might be accurate to say that NFKB is the master regulator of inflammation.  A number of cancers have hijacked this family of proteins for its own use.  And a number of cancers are also highly dependent on this pathway to be aberrantly expressed.  However, very few true inflammatory genes are oncogenes or tumor suppressors (the two types of genes that must be defective/mutated/changed) in all cancer cells.  So, the true/direct link between inflammation and cancer still needs further elucidation.

So the real question behind this issue is…;can we prevent cancer by reducing inflammation?  All NSAIDs class of drugs work mostly though blocking something known as Cox protein (or a set of proteins that work as signals inside the cell).  There are two major Cox proteins and one is regulated by pro-inflammatory proteins in the body and the other by stomach related factors (or gastrointestinal signals).  Aspirin blocks both of these but other NSAIDs work by blocking only one or the other.  However, to make a long story short, Cox2 inhibitors can have bad side effects including heart problems and many of these drugs were removed from the market after people started having heart troubles.  So, if drugs can be made that have less of this side effect but inhibit inflammation, perhaps they could be used by more people to help prevent cancer (ar at least reduce the chances of dying from certain cancers).  This will take time and there are no magic bullets.  We will see if the link between inflammation and cancer can really be used to save people’s lives in the future…but for now we have aspirin and that is one step in the right direction.

Dr. C

Thank you for reading: for more information on cancer see previous blog articles and visit Cancer Made Simple.

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