There are a great
many problems associated with attributing cause to diseases. Cancer is considered the
“jewel in the crown” of medical cures. S/he who can cure cancer will undoubtedly win
the Nobel Prize and be as famous as Jenner and Pasteur. However, it is seriously
problematic from the point of view of cause. At a recent guest lecture
to HKU, the Chairman of the Imperial Cancer Research Fund, the oldest and wealthiest in
the UK, the director, Sir Walter Bodmer, showed a slide indicating the only around 10% of
cancers were due to heritable factors, which he considered at great length. He failed to
discuss the other 90% of the most common diseases called cancer. With the exceptions of
very rare cancers, such as retinoblastoma, most cancers arise only in the presence of
certain environmental factors which have impacted over a lifetime. The longer a person
lives and their environment determines their exposure. Their body’s ability to detoxify
their environment is partly genotypically determined, but also depends on factors life
income (poor can’t afford adequate nutrition, such as fresh fruits, vegetables, clean
air), diet, and behaviour (toxin load, from smoking, alcohol use etc.)
“True” genetic cancers are very rare for a very good reason. They are
selected against.
