Researchers Map Tumor Differences in Young Colon Cancer Patients

Researchers from Dana-Farber Cancer Institute, Mass General Brigham, and the Broad Institute have identified cellular differences in colorectal tumors from younger and older patients, offering new directions for investigating why the disease increasingly affects younger adults. Published Thursday, October 29, 2026, in Nature Medicine, the study analyzed 189 tumors and more than 850,000 cells to help explain the biology of early-onset colorectal cancer and inform future prevention and treatment research.

According to the American Cancer Society, colorectal cancer rates among Americans younger than 50 increased by nearly 3 percent annually from 2013 through 2022. The disease is now the leading cause of cancer death in this age group.

The researchers examined tumors from patients in their 20s through their 90s, including 54 people diagnosed before age 50. Their analysis identified differences in tumor cell composition and gene expression that could help scientists investigate why younger patients develop the disease and why some cases are more advanced and difficult to treat.

Ana Anderson, a senior author and core faculty member of the Gene Lay Institute of Immunology and Inflammation at Brigham and Women’s Hospital, described the findings as a starting point for more targeted investigations.

“It’s been a bit of a black box,” said Ana Anderson. “Now we have a research direction. We have a path to follow and hopefully find something that’s really specific to this disease and that will be the basis for developing tailored therapies specifically for young-onset colon cancer.”

The team found that tumors in younger patients appeared to contain a higher proportion of stromal cells, which provide connective and structural support within tissues. Studies of other solid cancers have linked these cells to resistance to chemotherapy, although the findings do not establish that the same relationship applies to young-onset colorectal cancer.

Researchers also detected differences in gene expression in tumors from younger patients. These variations could help identify potential therapeutic targets, but additional studies are needed to determine their clinical significance.

Dr. Kimmie Ng, a senior author and director of the Young-Onset Colorectal Cancer Center at Dana-Farber Cancer Institute, said the dataset provides an unusually extensive resource for future research. According to Ng, it is the largest dataset assembled to date for colorectal cancer and includes the highest number of young patients.

“It gives a huge amount of hope,” she said. “It really serves as a guidepost to where we should direct our future research efforts.”

Researchers hope the findings will help clarify the biological mechanisms behind the rising incidence of colorectal cancer in younger adults. Previous research has associated the disease with dietary patterns, ultra-processed foods, and other lifestyle and environmental factors, but scientists also want to understand the cellular processes occurring within tumors.

Dr. John Paul Shen, an associate professor in the department of gastrointestinal medical oncology at the University of Texas MD Anderson Cancer Center, who was not involved in the study, said the detailed dataset could support experiments by research teams worldwide.

“There’s some very clear experiments that we might do in our lab or other people would do in their labs around the world,” said Shen. “That’s hugely valuable.”

Shen and other experts cautioned that the analysis, despite its extensive cellular detail, draws on a limited number of patients. Ng said the study population is consistent with what researchers generally know about young-onset colorectal cancer patients worldwide.

Dr. Christina Annunziata, senior vice president of extramural discovery science at the American Cancer Society, said further research involving other patient populations could expand the findings and help establish how broadly the observed differences apply.

“The research is necessary for us to understand why people are getting cancers early and what we can do about it,” she said.

Annunziata also emphasized the foundational role of the dataset in advancing research into early-onset disease.

Having the dataset, Annunziata said, is “an essential first step.”