[How Does Aging Contribute to Cancer?]

Advances in sequencing technology have been reported to show cancer driver mutations with aging in a variety of normal tissues at very small clone sizes. In the normal esophagus, prior to carcinogenesis, clones that had acquired driver mutations in esophageal cancer, mainly NOTCH1 mutations, during early life appeared multi-centrically. With aging, the number of driver mutations increased and the clones expanded. In the elderly, most of the normal esophagus was replaced by clones with driver mutations. In contrast, in normal colorectal epithelium, about 1% of crypts contain driver mutations even in the 50s. In normal hepatocytes, age-related mutations are rarely detected. These results suggest that the frequency of detection of driver mutations in normal tissues varies greatly among tissues. The panorama of aging and cancer remains veiled.