John M. Carethers

In a 2016 research review, John M. Carethers described a discovery from his own laboratory: the DNA mismatch repair system, which corrects copying mistakes when cells divide, also recognizes the chemotherapy drug 5-fluorouracil after it has been incorporated into DNA. The finding connected his laboratory science to a question asked in clinics every day: which colon tumors will respond to standard treatment, and which will not.

Carethers grew up in Detroit and found an early interest in medicine in his family's encyclopedias. He worked nearly thirty hours a week to put himself through Wayne State University and its medical school, graduating in 1989. He trained in internal medicine at Massachusetts General Hospital and completed a gastroenterology fellowship at the University of Michigan from 1992 to 1995.

His laboratory work concentrated on the genetics of colorectal cancer: hereditary syndromes such as Lynch syndrome, the mechanisms by which tumors progress, and the mismatch repair defects that shape how tumors behave and respond to treatment. The AACR Academy, which elected him a fellow, cited his leading-edge findings on colorectal cancer pathogenesis in patients with DNA mismatch repair defects and his genetic cohort studies. In 2012, he was elected to the Institute of Medicine, an honor his alma mater connected to his research on colon cancer genetics and screening.

Institutional leadership grew alongside the science. He spent thirteen years at the University of Michigan, where he held the C. Richard Boland Distinguished University Professorship, before UC San Diego named him vice chancellor for health sciences, effective January 1, 2023. The office oversees the School of Medicine, the Skaggs School of Pharmacy and UC San Diego Health.

As president of the American Gastroenterological Association in 2022 and 2023, he led discussions with federal officials about access to follow-up colonoscopies, a practical barrier between a positive screening test and treatment. He has also mentored students and younger researchers, including helping colleagues develop grant applications. In 2025, AACR selected him for its distinguished lectureship on cancer health disparities.

From Detroit to La Jolla, his research questions have stayed close to the same ground: what drives colon tumors, and who gets screened in time.