New research suggests that colon cancer may start developing in the first 10 years of life, years before symptoms occur and decades before most people think about screenings. Adults diagnosed with colon cancer before age 40 are three times more likely to have a special DNA mutation caused by childhood exposure to colibactin, a toxin from some E. coli. This could explain why the disease is occurring in younger adults with no traditional risk factors. If true, Dr. Michael Breen, a hematologist-oncologist at Advocate Health Care, has suggested expanding prevention and screening efforts to include people of all ages.