What about cancer resistance?

Two people. One smokes, the other a lifetime non-smoker. So why is it that the non-smoker develops lung cancer and the smoker doesn’t? Is it pure luck? Is it simply one of life’s ironies? Or is there a scientific explanation behind it?

The majority of research studies in oncology investigate what makes people susceptible to cancer. Most researchers look at susceptibility genes and risk factors. This is understandable because millions of people worldwide have cancer. Cancer is a major cause of mortality and the rates are rising: cancer is predicted to be the number one killer globally in the coming decade.

But what about the millions who do not get cancer? For every cancer victim, there are two people who escape the disease. Even some of the heaviest smokers don’t get lung cancer while the most health-conscious people do fall prey to this cruel disease. What do these cancer-free people have that the others don’t? Is this a matter of chance, or are there cancer-resistant genotypes?

Swedish professor George Klein is busy with a field of research in oncology that is neglected, almost overlooked – cancer resistance. He recently published a paper called “Toward a genetics of cancer resistance” in the Proceedings of the National Academy of Sciences.

In the course of his research, Klein has hypothesized five protective mechanisms that may protect people from cancer, namely:

• Immunological mechanisms. Individuals may differ in terms of immune system efficiency.
• Genetic mechanisms. Some people have more effective DNA repairing system than others. Those with specific DNA repair deficiency can develop certain types of cancer.
• Epigenetic mechanisms. Genetics involve the DNA itself while epigenetics involve gene expression. Different gene expressions can have different results.
• Intracellular mechanisms. This involves apoptosis or cell death, a defense mechanism within the cell itself. Apoptosis is triggered in some people but not in others.
• Intercellular mechanisms. The researchers believe there is a defense mechanism that makes cells watch their neighbors and sound the alarm when precancerous conditions are detected.

Klein is urging researchers to look into cancer resistance as well and not only into cancer susceptibility.

Evolution seems to have favored some relatively common resistance genes that protect the majority of humans against cancer development. One day, finding out how nature keeps most of us cancer-free could help identify and repair specific genetic mechanisms in the large minority of individuals who do suffer from cancer. However, …[according to the author] it’s premature to speculate exactly how understanding genetic resistance could help people who are susceptible to cancer.

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