England (Commonwealth Union) – Researchers have found that people who have a ‘skewed’ pattern in their immune blood cells have twice the possibility to develop cancer later in life.
A study led by King’s College London has given new insights on the way skewed X chromosome inactivation (XCI-skew) is linked to developing chronic disease. Basic genetics show us that in human males have the XY chromosomes and females have XX chromosomes, in every cell that has two X chromosomes generally in females 1 of the 2 is silenced, which is referred to as X chromosome inactivation (XCI). This occurs early in development and is fixed for every cell, making sure each body cell has 1 functional copy of the X chromosome.
The X that is silenced is chosen at random and so it is expected that each X will be silenced in half the cells. However, as we grow older and form new immune blood cells, some form a pattern of XCI, quite different to the expected 50:50 ratio, known as XCI-skew and it is unknown presently as to why this happens in certain people.
Scientists evaluated the health information of 1,575 females from TwinsUK, which is the biggest adult twin registry in the UK, having the most clinical details across the globe, discovering that individuals with this skewed pattern in their blood cells are twice as likely to get cancer in a 10-year period, and they score more for risk factors of getting cardiovascular disease as well. Additionally, they carried out a prospective 10-year follow-up study discovering that even slight XCI-skew showed a higher probability of future cancer diagnosis, in all types of cancer.
“From our results, we hypothesise that XCI-skew in blood tissue does not directly cause cancer later in life. Rather, XCI-skew is likely to be a marker of chronic inflammation, which can stimulate tumour growth,” said the lead author Dr Amy Roberts, Postdoctoral Research Fellow at the Department of Twin Research and Genetic Epidemiology.