Some people accumulate DNA mutations much faster than others, and that hidden difference may shape who gets cancer, a large new study suggests. Researchers from City of Hope and TGen published the findings in the journal Cancer Research.

The team compared mutations in healthy and cancerous tissues across seven organs: bladder, colon, esophagus, liver, lung, prostate and stomach. Cancer cells showed a median mutation burden more than four times higher than healthy tissue.

Three explanations were tested. The ‘tail hypothesis’ — that individuals with higher mutation rates are more likely to develop cancer — best fit the data. Even after accounting for age, some healthy people had up to eight times more mutations than others.

The finding could help explain why people who develop cancer often carry more mutations in their healthy cells too. The authors say measuring a person’s mutation rate could one day identify those at higher risk and guide more personalised prevention strategies.