Cancer, a group of diseases associated with abnormal cell growth continues to be one of the most frustratingly difficult to treat maladies of modern times. In a new discovery, scientists have found a way to identify the particular causes of a cancer by analysing its DNA.
Cause of cancer is written into DNA of tumours, scientists find, creating a ‘black box’ for origin of disease
The cause of cancer is written into the DNA of tumours, scientists have discovered, in a breakthrough which could finally show how much disease is attributable to factors like air pollution or pesticides.
They exposed stem cells to dozens of known carcinogens and recorded how each alters its DNA code as cancer forms. It provides a ‘fingerprint’ or ‘mutational signature’ of the underlying cause and could even show which was the biggest culprit.
The researchers have today released a catalogue of the signatures caused by 41 environmental agents linked to cancer so that scientists and doctors can understand its origin.
The human genetic code is written in molecules known as nucleotides, represented by the letters A, C, G and T. The new technique works by studying ‘spelling mistakes’ or mutations in DNA which occur because factors such as ultraviolet light, alcohol of tobacco smoke, such an A becomes a G.
As cells divide and multiply, they make copies of their DNA, so any spelling mistakes will be reproduced. Over time, the number of errors accumulates leading to uncontrolled cell growth – the development of tumours. And each cancer-causing factor changes the code in a slightly different way.
The technique is so powerful it can even show which individual chemicals in tobacco smoke were to blame for lung tumours.
The team also identified the fingerprints left behind by common chemotherapy drugs, some dietary chemicals and some present in diesel exhaust fumes, showing just how vulnerable human DNA is to environmental contaminants.