Douglas Brash, PhD

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

Departments & Organizations

Therapeutic Radiology: Radiobiology

Radiobiology & Radiotherapy

Yale Cancer Center: Radiobiology & Radiotherapy

Office of Cooperative Research


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. Recently the lab discovered that chemical excitation of electrons, "chemiexcitation", is a new mode of disease that uses the pigment melanin to create UV-like carcinogenic lesions even after UV exposure has ended. These results contribute to what is perhaps the best picture available of how a human carcinogen works. Another current project is identifying UV-hypersensitive genome regions for use as "genomic dosimeters" to assess a person's past sun exposure and future skin cancer risk.

Education & Training

PhD Ohio State University (1979)
BS University of Illinois, Engineering Physics (1973)
Postdoctoral Harvard Medical School
Postdoctoral Harvard School of Public Health

Honors & Recognition

  • Finsen Medal for lifetime achievement in photobiologyInternational Union of Photobiology (2014)

  • Achievement Award for Research in Skin Cancer/MelanomaAmerican Skin Association (2006)

  • Plenary AddressHungarian Dermatology Society, Lillafüred, Hungary (1998)

  • Biomedical Pilot Projects Research AwardCharles E. Culpeper Foundation (1997)

  • Finsen LectureInternational Association for Photobiology, Vienna (1996)

  • Arnold Rikli Award for Research in Human PhotobiologyInstitut Friedrich Wolff, Basel, Switzerland (1995)

  • Swebelius Cancer Research AwardSwebelius Foundation (1991)

  • Argall L. and Anna G. Hull Cancer Research AwardArgall L. and Anna G. Hull Foundation (1990)

Professional Service

  • Yale College Dean's Office (2007 - 2008) Coordinator, Office of Undergraduate Research, Yale College


  • Melanin Photosensitization Sao Paulo, Brazil; Grenoble, France; Toyohashi, Japan (2008)

    Professor Brash studies the role of melanin photosensitization in sun-sensitivity and skin cancer in collaboration with chemists at the University of Sao Paolo, Brazil , Fujita Health University, Japan, and the French Atomic Energy Agency, Grenoble.

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Contact Info

Douglas Brash, PhD
Lab Location
Brash LabHunter Building
15 York Street, Ste Suite 210

New Haven, CT 06510
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Mailing Address
Therapeutic RadiologyPO Box 208040
New Haven, CT 06520-8040

Curriculum Vitae

Research Image 1

Clone of p53-mutated keratinocytes in a 3D confocal image of an epidermal whole-mount of normal human skin.