Somatic mutation and clonal expansions in human tissues

Abstract

Recent sequencing studies on healthy skin and esophagus have found that, as we age, these tissues become colonized by mutant clones of cells carrying driver mutations in traditional cancer genes. This comment summarizes these findings and discusses their possible implications for our understanding of cancer, ageing, and other diseases.

Fig. 1

Mutant cell colonization of healthy esophageal epithelium with age. Each panel is a schematic illustration of a representative 1 cm² area of normal esophagus from three donors. The younger donor was a moderate smoker and the two older donors were non-smokers. Mutant clones are shown as circles randomly distributed in space. The number of mutant clones and their sizes are directly inferred from the sequencing data, with clone areas being estimated from the fraction of sequencing reads carrying each mutation in each sample (adapted from [3])