William Kaelin Wins Nobel Prize in Physiology or Medicine

Kaelin is the forty-ninth Harvard faculty member to win the Nobel. 

William G. Kaelin pictured in his home in Boston shortly after receiving the call from Sweden

William G. Kaelin | Photograph by Stephanie Mitchell/HPAC

William Kaelin, Farber professor of medicine, has won the Nobel Prize in physiology or medicine, the Nobel Foundation announced this morning. He shares the prize with Sir Peter J. Ratcliffe, of the University of Oxford, and Gregg Semenza ’78, of Johns Hopkins University, for their research on how cells adapt to changing oxygen levels. 

The team “discovered how cells can sense and adapt to changing oxygen availability. They identified molecular machinery that regulates the activity of genes in response to varying levels of oxygen,” according to an announcement from the Nobel Assembly at Karolinska Institutet. “The seminal discoveries by this year’s Nobel Laureates revealed the mechanism for one of life’s most essential adaptive processes. They established the basis for our understanding of how oxygen levels affect cellular metabolism and physiological function. Their discoveries have also paved the way for promising new strategies to fight anemia, cancer and many other diseases.”

Kaelin is the forty-ninth Harvard faculty member to win a Nobel Prize. His most recent predecessor, economics professor Oliver Hart won the 2016 Nobel Prize in economic sciences for his advances in contract theory.

Kaelin’s fellow winner Gregg L. Semenza ’78 is Armstrong professor of medicine at the Johns Hopkins University School of Medicine. A Hopkins press release notes that his research paves the way for the development of drugs that could kill cancer cells by cutting off the supply of oxygen a tumor needs to grow, and could also lead to medicines allowing tissues affected by conditions such as arterial disease to survive on low oxygen.

You might also like

Harvard Honors Its Oldest Alumni

At 97 and 101, Linda Cabot Black ’51 and William “Bill” Dubey ’46 led the way on Alumni Day.

Harvard College Dean Deming Launches Podcast

In interviews, he traces his guests’ circuitous routes to success.

Graduate Student Workers End Strike

Union members return to work without a contract, but with plans to continue bargaining.

Most popular

Ronny Chieng Tells Harvard to ‘Destroy AI’ as Graduates Cheer

The comedian and The Daily Show host gave the keynote address for Class Day 2026.

Meet Harvard’s 2026 Student Commencement Speakers

Two undergraduates and a Ph.D. candidate will address the graduating class on May 28.

Don’t Be A ‘Solo Superhero,’ Jonny Kim Tells Harvard Alumni

The astronaut, doctor, and Navy SEAL delivered keynote remarks on Alumni Day.

Explore More From Current Issue

Historical battle scene with soldiers in red and blue uniforms, flags waving, chaotic action.

The Harvard-Trained Doctor Who Urged a Revolution

Before his heroic death, General Joseph Warren was dubbed “the greatest incendiary in all of America.”

Colorful illustrated map of Colonial Cambridge and the Harvard College campus featuring buildings of the campus, houses, Cambridge Common, and the Charles River

250 Years Ago, Harvard Was Home to a Revolution

A look at the sights, sounds, and characters that put the University on the frontlines of history

White House and Harvard University buildings split diagonally with contrasting colors.

Harvard Weathers a Year of Turmoil

The federal government has launched unprecedented actions against the University. Here’s a guide.