Aziz Sancar: The Turkish-American Biochemist Who Won the 2015 Nobel Prize in Chemistry

Aziz Sancar is a Turkish-American biochemist and molecular biologist best known for describing nucleotide excision repair, the process cells use to remove DNA damaged by ultraviolet light and other agents. In 2015 he shared the Nobel Prize in Chemistry with Swedish researcher Tomas Lindahl and American biochemist Paul Modrich. Turkish Wikipedia's entry on Sancar describes the honor as recognizing research that mapped how cells repair damaged DNA and preserve their genetic information.

From Savur to a Career in Molecular Biology

Sancar was born on September 8, 1946, in Savur, a town in Turkey's Mardin Province, according to his biographical page on sancar.org. He graduated from Istanbul University's Faculty of Medicine in 1969 and practiced medicine in Turkey for two years before moving to the United States, where he earned a PhD in molecular biology from the University of Texas at Dallas in 1977, the same page states.

On the Carnegie Corporation of New York's honoree page, Sancar is quoted describing his family background.

After completing his PhD, Sancar worked as a postdoctoral researcher at Yale University's medical school from 1977 to 1982, according to sancar.org. He then joined the University of North Carolina at Chapel Hill's Department of Biochemistry and Biophysics in 1982, a date confirmed both by UNC's own profile of him and by UNC Lineberger Comprehensive Cancer Center. He now holds the title of Sarah Graham Kenan Professor of Biochemistry and Biophysics at the UNC School of Medicine.

Cracking the Mechanism of DNA Repair

Sancar's research mapped out nucleotide excision repair, a biological process in which specialized proteins locate a damaged section of DNA, cut it out, and replace it with a correctly synthesized segment. UNC Lineberger's award announcement for Sancar notes that his lab also discovered that the chemotherapy drug cisplatin kills cancer cells partly by interfering with this same excision-repair pathway, and that his group published a landmark 1996 study describing human DNA excision repair in detail.

His research extended beyond repair mechanisms into the body's internal clock. According to UNC Health's 2025 profile of Sancar, his laboratory also identified cryptochrome proteins, which help regulate circadian rhythms, and more recently worked on a biochemical approach aimed at treating brain tumors.

The 2015 Nobel Prize in Chemistry

The Royal Swedish Academy of Sciences awarded the 2015 Nobel Prize in Chemistry jointly to Lindahl, Modrich and Sancar, crediting each for working independently over several decades on complementary DNA-repair mechanisms, as summarized on Turkish Wikipedia's entry on Sancar. The Carnegie Corporation's page on Sancar cites the Nobel committee's statement that the discoveries "increased our understanding of how the living cell works, the causes of cancer and aging processes."

Rather than keeping the prize money, Sancar and his wife, Gwendolyn, used the $310,000 award to establish the Aziz & Gwen Sancar Foundation, which supports Turkish-American cultural exchange and Turkish students at UNC Chapel Hill, according to the Carnegie Corporation page. Separately, Turkish Wikipedia's article states that Sancar donated his Nobel medal and certificate to the Atatürk Museum in Ankara, saying that what led him to the prize was Atatürk's educational revolution in Turkey.

Recognition and Ongoing Work

Sancar became the first Turkish-American elected to the United States National Academy of Sciences in 2005, according to the Carnegie Corporation's biographical page, which also notes his membership in the National Academy of Medicine. In February 2020, UNC Lineberger presented him with its 2019 Hyman L. Battle Distinguished Cancer Research Award, a $25,000 prize recognizing cancer research at UNC Chapel Hill.

As of UNC Health's October 2025 profile, Sancar was still an active professor at age 79, having mentored more than 35 graduate students and more than 55 postdoctoral researchers over roughly four decades at UNC. The same profile reports that he continues to teach molecular biology courses and credits his lab team for the discoveries attributed to him.

• Described nucleotide excision repair, the pathway cells use to remove UV-induced DNA damage
• Found that the cancer drug cisplatin disrupts this same excision-repair pathway in tumor cells
• Co-discovered cryptochrome proteins that help regulate the body's circadian clock
• Published a 1996 landmark study detailing human DNA excision repair
• Worked on mapping DNA repair sites across the human genome to identify cancer vulnerabilities