Douglas E Brash PhD

Senior Research Scientist in Therapeutic Radiology and in Dermatology and Clinical Professor of Therapeutic Radiology

Departments & Organizations

Radiobiology & RadiotherapyDermatology: Skin Diseases Research Center, Yale | Therapeutic Radiology/Radiation Oncology: RadiobiologyRadiobiology and Radiotherapy


Dr. Brash received his BS in Engineering Physics from the University of Illinois, minoring in Physiological Psychology. After receiving a PhD in Biophysics, he began elucidating the steps leading from ultraviolet light photons to human skin cancer. As a postdoc at Harvard, he found that UV-induced mutation hotspots in E. coli occur at the same gene positions as (6-4) photoproducts and cyclobutane dimers: UV wasn't elevating random genomic instability. At the National Cancer Institute, he proved these photoproducts were mutagenic. Upon moving to Yale, his lab used the distinctive UV mutation pattern to identify genes mutated by sunlight in causing skin cancer: p53 in squamous cell carcinoma and its actinic keratosis precursor, and p53 and PTCH in basal cell carcinoma. They then showed p53 to be a key element of UV-induced apoptosis, preventing damaged cells from becoming mutants. Because the multiple-genetic-hit model of cancer predicts that our bodies harbor cells mutated in just one or another of the genes needed for cancer, the lab then sought p53-mutant cells in normal skin. These cells were not only present but were already proliferating as clones and were astonishingly common – many people carry 60,000 clones, occupying almost 5% of their epidermis. Switching to mice revealed that clonal expansion is driven by physiology, not by adding mutations. One mechanism is the mutant's resistance to UV-induced apoptosis. Another is UV's ability to tilt a clone's balance of progenitor cells and differentiating cells toward self-renewal of the progenitors. Understanding the role of p53 and UV in this cell fate decision is the lab's current focus. These results contribute to what is perhaps the best picture available of how a human carcinogen works.


  • B.S., University of Illinois , 1973
  • Ph.D., Ohio State University , 1979

Selected Publication

  • Premi, S, Wallisch, S, Mano, CM, Weiner, AB, Bacchiocchi, A, Wakamatsu, K, Bechara, EJH, Halaban, R, Douki, T, and Brash, DE. Chemiexcitation of melanin derivatives induces DNA photoproducts long after UV exposure. Science 347:842-7, 2015.

Latest Honor and Recognition

  • Argall L. and Anna G. Hull Cancer Research Award(1990) , Argall L. and Anna G. Hull Foundation
Download on the Apple App Store