Discussion by: Dsquared
Let me start off by saying that I am an engineer – not a scientist or biologist. This short article is obviously intended to pose a question rather than be an academic paper; however, I hope that it will encourage a new thought process into the subject of evolution and the possible links with cancer.
Some years ago, I read Richard Dawkins fascinating book – ‘The Blind Watchmaker’ and have often wondered what key events favourably change the human evolutionary process. Well known processes are the long term development of bi-pedalism. In his book, Richard Dawkins also describes the gradual development of the eye as a useful tool in humans and animals. These examples I guess are triggered by the need to become more efficient or obtain an edge on competitors.
But what if a trigger event (on the cell structure) is too rapid for the biological process to adapt? I am thinking of the deadly external ‘inputs’ to living things such as chemicals and radiation. These external influences are also well known triggers for cancer – which if my understanding is correct, cause cells to mutate and grow at alarming rates. The outcome is certainly not a favourable one.
Normally, new ‘trigger inputs’ from an animal’s environment are handled very gradually in terms of evolutionary change.
My question: Is the body (primarily the affected cells) trying to ‘cope’ with the new situation and shift into a new evolutionary gear?
Has the DNA in people with low sensitivities to cancer been ‘programmed’ over many generations by similar, but less rapid trigger events that modify the DNA and essentially render the cells immune? Put another way, in susceptible people, are cancerous cells a failed DNA attempt to deal with a rapidly challenging external environment?
A key point in terms of susceptibility is that humans appear to have different sensitivities to cancer. The well known example of…..” my Grandfather smoked 30 a day and lived until he was 90” comes to mind.
For some people, examples of ‘modern’ challenging external environments are:
- Man-made chemicals.
- Drugs (such as cigarettes).
- Continued exposure to high & low frequency electro-magnetic radiation (ultra-violet, micro waves, power lines)
Again, people with a developed low sensitivity tend not to suffer ill effects , whilst people with DNA that has not come through the same evolutionary process may develop cancers.
I do not know what research has been performed on the occurrence of cancers within the animal population – especially animals that are close to the human environment (pets, farm animals etc).
However, I reason that in the natural world, the count would be low in relation to humans as the animal would be severely disadvantaged and tend not survive to breed.
Cancer is obviously NOT a modern problem, however, this must be primarily attributed to the lack of accurate records and true understanding a hundred years ago. It would be extremely interesting to obtain mortality statistics from perhaps 500 years ago. The results may give a further insight into the multi-causal nature of cancer.
To conclude, is cancer a natural and virtually unstoppable side effect connected with the continuing evolutionary process that all living things need to engage with?
Dave Dudley BA