As we age, we acquire genetic changes (mutations) in the cells responsible for blood production (haematopoietic stem cells), a phenomenon termed “clonal haematopoiesis”. Recent studies, using novel sequencing methods, have shown that as many as 95% of healthy individuals over the age of 60 has evidence of clonal haematopoiesis detectable in their blood. We know that this increases the risk of these individuals developing blood cancers, but at the moment we are unable to predict which individuals are most at risk. To address this, we need a better understanding of how the growth/ survival of the blood cells harbouring these acquired mutations changes over time (the ‘evolutionary dynamics’) and, ultimately, how this differs in individuals who subsequently develop blood cancers.

A number of large studies have been published looking at clonal haematopoiesis in population-based studies (e.g. Jaiswal 2014, Genovese 2014), but there are two key things that these studies lack; longitudinal data and data from very young individuals (the mean age in these studies was ~50-60 years). Having data from young individuals will allow us to see exactly when these mutations start to appear and having samples collected from the same individuals at multiple time-points (longitudinal data), we can truly assess how the affected cells (clones) in the same individual change over time.