Science 362, 911–917 (2018)

The epithelial cells of the esophagus accumulate somatic mutations during aging, and cancer-associated mutations are selected for.

It is known that cells accumulate mutations with age, but the extent to which this occurs and the relationship with cancer development are largely unknown.

Scientists in the United Kingdom sequenced esophageal epithelial tissue from nine individuals of varying ages. They found that by middle age the cells lining the esophagus carry an average of around 2,000 somatic mutations per cell. They also found that cancer-associated mutations were positively selected for. While most genes under selection were known drivers of esophageal squamous carcinoma, mutations in the NOTCH1 gene were several times more common in normal esophagus than in esophageal cancers.