Smoking linked to loss of the Y chromosome
“It will be important to test whether this loss directly contributes to an increase in cancer cases and deaths in men" - Professor Charles Swanton, Cancer Research UK
As the Y chromosome is only found in cells in men, the researchers believe these findings could help explain why smoking is a greater risk factor for men developing cancer.
Previous research from the team, based at Uppsala University in Sweden, had shown that loss of the Y chromosome in these cells was linked to the disease. Now the team have shown that this loss is linked to smoking.
Professor Charles Swanton, based at Cancer Research UK's London Research Institute, said: "We know that men have a higher risk of developing and dying from most of the cancers that affect both men and women - and this study might help to explain why”.
The team combined data from three independent studies, covering just over 6,000 men, and analysed genetic information to calculate the degree of Y chromosome loss. They also took into account the age of the men, their exercise habits, cholesterol levels, education status, alcohol intake, and many other health and behavioural factors.
The team also found that the more a man smoked the more likely his cells were to have lost the Y chromosome. But, the association only affected current smokers. Smokers who had quit showed similar levels of Y chromosome loss as men who had never smoked.
Lars Forsberg, lead author of the study, hopes that this information will motivate smokers to quit as the data suggest that the loss of the Y chromosome could be counteracted if men kick the habit.
But experts are still unclear as to why loss of the Y chromosome in blood cells is connected with the development of cancer. Some think it could be that immune cells, which have lost their Y chromosome, have a reduced capacity to fight cancer cells.
“It will be important to test whether this loss directly contributes to an increase in cancer cases and deaths in men," added Swanton.
Professor David Phillips, a Cancer Research UK expert in how chemicals cause cancer, agreed: “Many smoking-related cancers are more common in men because more men than women have smoked.
“This latest study is interesting, but the findings will require further investigation to understand if smoking is actually causing loss of the Y chromosome or whether the events are coincidentally, rather than causally, linked,” he added.