Are the genetic mutations that lead a normal cell to turn into a cancerous cell mainly due to chance or to our way of life? In other words, is cancer “the fault of bad luck”.
For years, the question has been bothering scientists and their studies often contradict previous ones.
The one published in Science and reported by AFP is based on a mathematical model including 32 types of cancer and epidemiological data from 69 countries and representing 4.8 billion people.
The conclusions of the team from the Johns Hopkins University Cancer Center must be interpreted with great caution, even if this work is a milestone.
“Each time a normal cell divides and copies its DNA to produce two new cells, it makes many mistakes,” explains Cristian Tomasetti, professor of biostatistics and co-author of the study.
This phenomenon, long underestimated by scientists, according to him, is an important cause of genetic mutations responsible for cancer.
The Centre’s co-director, Dr. Bert Vogelstein, goes further. “66% of cancerous mutations result from errors when cells divide, while 29% are due to environmental factors and lifestyle and 5% to heredity,” he says.
In 2015, recalls AFP, another study, published in Natureunderlined that environmental factors, such as smoking, chemical substances or exposure to the sun’s ultraviolet rays were determining factors in the appearance of cancers.
For their part, researchers at the Johns Hopkins Center managed to quantify their analysis by type of tumor. 77% of pancreatic cancers result from a random DNA error in cell division, 18% from other factors such as tobacco or alcohol and 5% from heredity. For the prostate and the brain, 95% of cancers are due to chance in cell division.
Conversely, our way of life, mainly tobacco, is responsible in most cases (65%) for lung cancer.
So who to believe? Should we rely on fate and ignore prevention advice and public health actions to avoid cancer? No, of course. 40% of them could be avoided by a healthy lifestyle. Dr. Bert Vogelstein even calls for this: “We must continue to encourage the public to avoid carcinogenic chemical agents or lifestyles that increase the risk of developing cancerous mutations”.
