Photo of R. Stephen Lloyd, Ph.D.

R. Stephen Lloyd Ph.D.

  •      (503) 494-9957
    • Professor Oregon Institute of Occupational Health Sciences
    • Professor of Molecular and Medical Genetics School of Medicine
    • Molecular and Medical Genetics Graduate Program School of Medicine
    • Program in Molecular and Cellular Biosciences School of Medicine
    • Cancer Biology Graduate Program School of Medicine

Dr. R. Stephen Lloyd received his BS in Biology from Florida State University in 1975, majoring in marine pollution biology. His research interests turned to cancer chemotherapy and in 1979, he earned his Ph.D. in Molecular Biology from the University of Texas Graduate School of Biomedical Sciences in Houston, TX. After learning about mechanisms by which DNA can be damaged, he began his career in DNA repair as a postdoctoral fellow at Stanford University in the laboratory of Dr. Philip Hanawalt. Following two years at Stanford, he worked for two more years for a genetic engineering company, before joining the Biochemistry Department at Vanderbilt University in 1983. In his ten-year stay at Vanderbilt, Dr. Lloyd rose through the ranks to Full Professor, and his research focused on both DNA repair and molecular mutagenesis. He was then recruited to the Center for Molecular Science at the University of Texas Medical Branch in which the faculty exclusively specialized in DNA repair mechanisms. During his twelve years at UTMB, he also became the Director of two Centers in Environmental Toxicology. In August 2003, he, along with his wife, Dr. Amanda K. McCullough was recruited to join the CROET faculty at OHSU. Together they have both separate and joint research projects in the research areas described below.

Areas of interest

  • Strategies to prevent sunlight-induced skin cancer via the topical introduction of repair enzymes into human cells
  • The mechanisms by which the loss of a DNA repair enzyme can lead to the clinical manifestations of Metabolic Syndrome - a constellation of diseases (obesity, fatty liver disease, insulin resistance and hypertension) that affect >45 million Americans
  • Mutagenic potential of alkyl-substituted and unsubstituted Fapy-dG adducts
  • Molecular mechanisms for the repair and replication of DNA-protein crosslinks
  • Replication bypass of DNAs containing interstrand DNA crosslinks


  • B.S., Florida State University, Tallahassee Florida United States 1975
  • Ph.D., University of Texas Houston Graduate School of Biomedical Sciences, Houston Texas United States 1979

Honors and awards

  • Awards: Editor’s Choice Award for Environmental and Molecular Mutagenesis for Sha Y, Minko IG, Malik CK, Rizzo CJ, Lloyd RS. Error-prone replication bypass of the imidazole ring-opened formamidopyrimidine deoxyguanosine adduct. Environ Mol Mutagen. 2017 May;58(4):182-189. PMID:28436537 PMCID: PMC5476229

Memberships and associations

  • American Association for the Advancement of Science (AAAS)
  • Environmental Mutagenesis & Genomics Society
  • Federation of the American Societies of Experimental Biology


  • NEIL1 protects against aflatoxin-induced hepatocellular carcinoma in mice. Vartanian, V., Minko, I. G., Chawanthayatham, S., Egner, P. A., Lin, Y. C., Earley, L. F., Makar, R., Eng, J. R., Camp, M. T., Li, L., Stone, M. P., Lasarev, M. R., Groopman, J. D., Croy, R. G., Essigmann, J. M., McCullough, A. K. & Lloyd, R. S. Apr 18 2017 In : Proceedings of the National Academy of Sciences of the United States of America. 114, 16, p. 4207-4212

  • Catalysts of DNA Strand Cleavage at Apurinic/Apyrimidinic Sites. Minko, I. G., Jacobs, A. C., De Leon, A. R., Gruppi, F., Donley, N., Harris, T. M., Rizzo, C. J., McCullough, A. K. & Lloyd, R. S. Jul 1 2016 In : Scientific Reports. 6, 28894

  • DNA polymerase ζ limits chromosomal damage and promotes cell survival following aflatoxin exposure.  Lin, Y. C., Owen, N., Minko, I. G., Lange, S. S., Li, L., Stone, M. P., Wood, R. D., McCullough, A. K. & Lloyd, R. S. Nov 29 2016 In : Proceedings of the National Academy of Sciences of the United States of America. 113, 48, p. 13774-13779

  • Enhanced sensitivity of Neil1−/− mice to chronic UVB exposure.  Calkins, M. J., Vartanian, V., Owen, N., Kirkali, G., Jaruga, P., Dizdaroglu, M., McCullough, A. K. & Lloyd, R. S. Dec 1 2016 In : DNA Repair. 48, p. 43-50

  • Small Molecule Inhibitors of 8-Oxoguanine DNA Glycosylase-1 (OGG1). Donley, N., Jaruga, P., Coskun, E., Dizdaroglu, M., McCullough, A. K. & Lloyd, R. S. Oct 16 2015 In : ACS Chemical Biology. 10, 10, p. 2334-2343

  • Error-prone replication bypass of the primary aflatoxin B1 DNA adduct, AFB1-N7-Gua. Lin, Y. C., Li, L., Makarova, A. V., Burgers, P. M., Stone, M. P. & Lloyd, R. S. Jun 27 2014 In : Journal of Biological Chemistry. 289, 26, p. 18497-18506

  • Molecular basis of aflatoxin-induced mutagenesis-role of the aflatoxin B1-formamidopyrimidine adduct. Lin, Y. C., Li, L., Makarova, A. V., Burgers, P. M., Stone, M. P. & Stephen Lloyd, R. 2014 In : Carcinogenesis. 35, 7, p. 1461-1468 8 p., bgu003

  • Pyrosequencing: Applicability for studying DNA damage-induced mutagenesis. Minko, I. G., Earley, L. F., Larlee, K. E., Lin, Y. C. & Lloyd, R. S. Oct 1 2014 In : Environmental and Molecular Mutagenesis. 55, 8, p. 601-608

  • Inhibition of DNA glycosylases via small molecule purine analogs. Jacobs, A. C., Calkins, M. J., Jadhav, A., Dorjsuren, D., Maloney, D., Simeonov, A., Jaruga, P., Dizdaroglu, M., McCullough, A. K. & Stephen Lloyd, R. Dec 9 2013 In : PLoS One. 8, 12, e81667

  • Inhibition of HIV-1 Reverse Transcriptase-Catalyzed Synthesis by Intercalated DNA Benzo[a]Pyrene 7,8-Dihydrodiol-9,10-Epoxide Adducts. Chary, P., Beard, W. A., Wilson, S. H. & Lloyd, R. S. Sep 19 2013 In : PLoS One. 8, 9, e72131

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