New research says that bad luck plays a bigger role in the development of cancer than previously believed, lifestyle; you can be a prey of cancer even if you live a healthy life.
A new study by US scientists shows random changes or ‘mistakes’ in DNA when cells are dividing cause nearly two-third of all cancers in humans. These changes are neither caused by external factors loke smoking or exposure to harmful chemicals, nor by hereditary factors. They are chance event occurring at the molecular level. In other word, cancer can strike anybody.
Human bodies grow by constant division of cells, starting from the first cell formed by a fusion of the male sperm with the female egg. The culprit is our own genetic code when cells divide out of the blue. Each time a normal cell divides and copies its DNA to produce two new cells, it makes multiple mistakes.
“These copying mistakes are a potent source of cancer mutations that historically have been scientifically undervalued, and this new work provides the first estimate of the fraction of mutations caused by these mistakes,” said the research by John’s Hopkins University in the journal ‘Science’.
The study involved a statistical analysis of cancer data from 69 countries, including India, representing 4.8 billion people, more than half of the world’s population.
However, Irish scientist Seamus Martin, professor of Medical Genetics at Trinity College, yesterday said that while the study added to our insight into cancer we should still avoid risk factors, such as smoking, soaking up the sun, drinking too much alcohol and try to maintain a healthy diet and weight.
The researchers studied all the 32 cancer types and estimated that 66% of cancer mutations result from copying errors, 29% can be attributed to lifestyle or environmental factors, and the remaining 5% are inherited. They found a strong correlation between cancer incidence and normal cell divisions among 17 cancer types, regardless of the countries’ environment or stage of economic development.
“We need to continue to encourage people to avoid environmental agents and lifestyles that increase their risk of developing cancer mutations,” co-author Bert Vogelstein emphasized.
Martin pointed out at least 50pc of major cancers are preventable and there were established a link between lung cancer and smoking. The more we damage our body by unhealthy habits, the more risk we are of developing cancer mutations.
Studies on cancer patients across the world have shown that approximately 40 % of cancer can be prevented by avoiding unhealthy environments and lifestyles. But this study explains why cancer is known to strike people who follow all the rules of healthy living — nonsmoker, healthy diet, healthy weight, little or no exposure to known carcinogens — and have no family history of the disease.
The common types of cancer, breast and prostate, were not analyzed as the researchers could not find a consistent rate of stem cell division in those tissues. Smoking accounts for a fifth of all cancers worldwide.
Different types of cancer have different origins. For example, in pancreatic cancer, 77% are due to random DNA copying errors, 18% to environmental factors, such as smoking, and the remaining 5% to heredity. In other cancer types, such as those of the prostate, brain or bone, more than 95% of the mutations are due to random copying errors.