‘EXIT-gene is proof of why cancer is less frequent in women’
Women wear may have more genes that protect against cancer than men. It could explain why cancer occurs more frequently in men than in women.
Earlier research showed that a form of leukemia was caused by a mutation in a gene called KDM6A, which is linked to the x chromosome. In the embryo-formation of girls is one of the x chromosomes is turned off, which would mean that women and men are equally likely to have on the development of cancer.
However, it turned out that some of the genes on this inactive x-chromosome of the dormant cells ‘escape’ and functioning normally. This ‘wake-made’ genes appear to be a working copy of KDM6A and have exactly the opposite effect of the gen. The gene protects the cell against mutation and developing cancer.
The researchers dubbed these specific cells to ‘EXITS’. “This theory suggests that cells from men only have a harmful mutation in one of the EXIT-genes necessary for cancer to develop. Female cells have mutations in both copies,” says Andrew Lane, one of the authors of the study.
To test this hypothesis, the researchers have taken, examined more than 4,000 tumors that in total belonged to 21 types of cancer. It was checked whether the found deviations frequently occurred in male or in female cells.
The results were striking: of the nearly eight hundred genes only on the X chromosome occurred, there were six that are frequently mutated in men than in women. At the other 18.000 genes, there was no difference to notice when the number changes.
“The fact that the genes that are frequently mutated in men, exclusively on the X-chromosome were found, and that the majority of them likely to EXIT the genes, is convincing evidence for our theory,” says Lane. “The protection resulting from the copies in the female cells helps to explain why many types of cancer occur less often in women and girls.”
“Almost for each type of cancer is that it occurs more frequently in men than in women. In some cases it is only a few percent difference, but in other species, men have two to three more likely to get the disease. From data of the American Cancer Institute shows that men, on average, twenty percent more likely to get cancer.”
The research is published in Nature Genetics.