Thelma Flournoy Brumfield Dunn (6 February 1900–31 December 1992), medical researcher, was born in Renan, Pittsylvania County, and was the daughter of Effie Flournoy Thornton Brumfield and William Andrew Brumfield. Her father was a physician who later became assistant commissioner of the Virginia State Board of Health and served during the 1920s as college health officer and professor of hygiene at Virginia Agricultural and Mechanical College and Polytechnic Institute (later Virginia Polytechnic Institute and State University). Brumfield attended public schools in Richmond and Lynchburg. She enrolled at Cornell University, transferred to Westhampton College in Richmond for the 1919–1920 academic year, and then returned to Cornell, where in 1922 she won the Guilford Prize for excellence in English prose composition with an essay entitled "Virginia Tobacco." That year she received an A.B. with honors in entomology.

In the autumn of 1922 Brumfield enrolled in the department of medicine at the University of Virginia, where she later recalled that her male colleagues treated her with respect despite the scarcity of female students on campus. She received an M.D. in June 1926 and the next month began an internship at Bellevue Hospital in New York City. The following July she returned to the University of Virginia's department of medicine as an instructor in bacteriology and pathology. Promoted to assistant professor in 1928, she served as acting chair of the department of pathology during the 1929–1930 academic year. On 26 December 1929 in Prince Edward County, Brumfield married William LeRoy Dunn, a physician who had been her classmate in medical school. About 1930 they moved to Washington, D.C., and then about 1940 to Arlington County. Later they lived in Chevy Chase, Maryland. Their one daughter and two sons included John Thornton Dunn, a medical researcher who specialized in thyroid disorders and led international efforts to eliminate iodine deficiency.

After a six-year hiatus from professional medicine, Dunn volunteered in 1936 as a laboratory assistant in the department of pathology at the George Washington University School of Medicine in Washington, D.C. She was appointed clinical instructor of pathology in 1939 and associate in pathology in 1941, positions that allowed her to work part-time while raising young children. Dunn resigned in 1942 to accept a fellowship at the National Cancer Institute, where she worked for the next twenty-eight years. In 1947 she became a staff pathologist, and she later took charge of the cancer induction and pathogenesis section of the laboratory of pathology.

Dunn's work focused on the origins and development of cancer in laboratory mice. She co-wrote the first NCI monograph, Mammary Tumors in Mice (1945), which identified a filterable virus as the agent of murine breast cancer. With a colleague at the institute, she developed methods of inducing malignant tumors in the stomachs and intestines of experimental animals and studied the behavior of the resulting cancer cells. Dunn frequently presented her findings in articles published in the Journal of the National Cancer Institute, including an influential 1954 paper that offered a comprehensive review of the reticuloendothelial system in laboratory mice and proposed a method of classification for tumors. She later devised a widely used classification scheme for mouse mammary tumors and lent her name to a type of murine bone cancer known as the Dunn osteosarcoma, first observed in her laboratory, which proved useful to researchers because it closely resembled the human version of the disease. Dunn conducted what she described as the first experiment in which a human birth control compound was given orally to mice, and in 1969 she reported that prolonged ingestion of the pills had caused uterine cancer in all the test animals. Though she noted that the mice had received much higher doses than did women who used the pills as directed, her research contributed to a wave of caution about oral contraceptives.

In May 1958 Dunn and five other American medical scientists, all female, embarked on a one-month tour of medical facilities in the Soviet Union as part of an exchange program the State Department organized. The following November, the American Medical Women's Association named her one of its eleven Women of the Year. On 1 April 1959 Dunn was elected president of the Washington Society of Pathologists, Inc. That year she joined the board of the American Association for Cancer Research, and in 1960 she was elected vice president and president-elect. She assumed the presidency in April 1961. Dunn was one of six female federal employees in February 1962 to receive the Federal Woman's Award for outstanding contributions in government service, and the United States Department of Health, Education, and Welfare presented her that year with a Distinguished Service Medal. She received honorary doctorates from the Woman's Medical College of Pennsylvania (1962) and the University of Perugia, in Italy (1969). Recognized internationally as an authority on the pathology of mice, she was also known as a generous collaborator and as an attentive mentor to young researchers.

After her retirement from the National Cancer Institute in 1970, Dunn moved to Charlottesville. She maintained a connection with the NCI by serving as a consultant to its Registry of Experimental Cancers, a collection of pathological materials documenting naturally occurring and artificially induced tumors in laboratory animals. Dunn published The Unseen Fight Against Cancer (1975), a description of experimental cancer research for the general reader. About 1980 she moved to Lynchburg, where her husband died on 14 November 1982. Thelma Flournoy Brumfield Dunn died of congestive heart failure at a Lynchburg retirement home on 31 December 1992 and was buried in Hollywood Cemetery, in Richmond.

Sources Consulted:
Personnel Record (with self-reported birth date), 18 July 1939, George Washington University, Washington, D.C.; Marriage Register, Prince Edward Co., Bureau of Vital Statistics, Commonwealth of Virginia Department of Health, Record Group 36, Library of Virginia; Thelma Brumfield Dunn Papers and interview of Dunn and W. LeRoy Dunn by Charles E. Moran, 28 Jan. 1976, both Small Special Collections Library, University of Virginia, Charlottesville, Va.; publications include Dunn, "Normal and Pathologic Anatomy of the Reticular Tissue in Laboratory Mice, with a Classification and Discussion of Neoplasms," Journal of the National Cancer Institute 14 (June 1954): 1281–1433, and The Unseen Fight Against Cancer: Experimental Cancer Research—Its Importance to Human Cancer (1975); Washington Post, 17 Nov. 1958, 8 Apr. 1959, 25 Mar. 1969, 15 Jan. 1970; Journal of the American Medical Women's Association 13 (Dec. 1958): 512–513; Medical Annals of the District of Columbia 28 (May 1959): 301; Commonwealth 29 (May 1962): 12; obituaries in Lynchburg News and Advance, 1 Jan. 1993, Charlottesville Daily Progress and Richmond Times-Dispatch, both 3 Jan. 1993, and Washington Post, 4 Jan. 1993.

Image courtesy of the Office of NIH History and the U.S. National Library of Medicine, Harold L. Stewart Papers.

Written for the Dictionary of Virginia Biography by Jennifer R. Loux.

How to cite this page:
Jennifer R. Loux,"Thelma Flournoy Brumfield Dunn (1900–1992)," Dictionary of Virginia Biography, Library of Virginia (1998– ), published 2016 (http://www.lva.virginia.gov/public/dvb/bio.asp?b=Dunn_Thelma_Flournoy_Brumfield, accessed [today's date]).

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