Skip to Content
Discovering the causes of cancer and the means of prevention

DCEG Appoints Three New Tenure-Track Investigators

In spring 2015, Jonathan Hofmann, Ph.D., M.P.H., and Stella Koutros, Ph.D., were appointed as tenure-track investigators in the Occupational and Environmental Epidemiology Branch (OEEB). Cari Kitahara, Ph.D., was appointed as a tenure-track investigator in the Radiation Epidemiology Branch (REB).

Jonathan Hofmann: Investigating Agricultural Exposures and Cancer Etiology

Jonathan Hofmann

Dr. Hofmann evaluates the role of agricultural exposures in the etiology of multiple myeloma and other cancers. He serves as co-principal investigator of the study of Biomarkers of Exposure and Effect in Agriculture (BEEA), a molecular epidemiologic investigation in the Agricultural Health Study. He also works to understand the biological mechanisms that influence multiple myeloma development and progression, in particular those related to obesity and immune dysregulation.

In addition, Dr. Hofmann investigates the etiology of renal cell carcinoma, with a focus on understanding factors that contribute to the racial disparities in this malignancy. He serves as co-principal investigator of the U.S. Kidney Cancer Study, a population-based case-control study of blacks and whites in Detroit and Chicago. Dr. Hofmann is also conducting molecular and genetic studies of renal cell carcinoma, including evaluations of gene-environment interactions.

In 2008, Dr. Hofmann received his Ph.D. in epidemiology from the University of Washington, after which he joined OEEB as a postdoctoral fellow. He became a research fellow in OEEB in 2011.

Stella Koutros: Evaluating Occupational Exposures as Cancer Risk Factors

Stella Koutros

Dr. Koutros’s research involves the design and conduct of epidemiologic investigations to evaluate occupational exposures as potential risk factors for cancer. She employs state-of-the-art exposure assessment methods and molecular studies within highly exposed populations to identify and clarify the biological mechanisms underlying chemical-induced carcinogenesis. Dr. Koutros is particularly interested in the interaction between these exposures and inherited genetic variation, also known as gene-environment interaction, as well as the interplay between somatic variation and alterations at the tumor level and chemical exposures.

Within the Agricultural Health Study, Dr. Koutros and her collaborators are evaluating whether pesticide exposure influences cancer risk. In particular, work in the study has shown an increased risk of aggressive prostate cancer with exposure to specific organophosphate insecticides.

Currently she is leading efforts within large case-control studies of bladder cancer to identify important occupational exposures that might influence risk, in particular with exposure to diesel exhaust. In addition, she is co-principal investigator of the largest study of acrylonitrile workers in the world and is helping to elucidate associations with cancer mortality to provide the most powerful epidemiologic evidence to date regarding acrylonitrile’s carcinogenicity to humans.

Dr. Koutros received her M.P.H. and Ph.D. in epidemiology from Yale University in 2008. She conducted her doctoral work through the Yale-NCI partnership training program in cancer epidemiology; upon completion, she became a postdoctoral fellow in OEEB and was later promoted to research fellow.

Cari Kitahara: Exploring Cancer Risk Associated with Ionizing Radiation

Cari Kitahara

Dr. Kitahara studies cancer risks associated with occupational exposure to low-dose ionizing radiation from emerging medical practices and procedures. Much of her current work focuses on nuclear medicine procedures (i.e., those involving radionuclides). Findings from these studies can inform current radiation protection practices for medical radiation workers and, more broadly, improve our understanding of the impact of low-dose radiation exposure on the risk of cancer in the general population.

Dr. Kitahara also investigates more broadly the etiology of radiosensitive tumors, including thyroid cancer and glioma. Her research utilizes data from large prospective studies to address long-standing and new hypotheses regarding the influence on risk of certain exposures, such as obesity, diet, smoking, and hormone use, across the life course.

Some examples of this work include a large pooled analysis of five prospective NCI studies on lifestyle-related factors and thyroid cancer risk. Dr. Kithara has expanded this effort to include 22 prospective studies from the NCI Cohort Consortium. In addition, using data from the GliomaScan Consortium, Dr. Kitahara and colleagues evaluated the association for height and history of diabetes, as well as genetic polymorphisms, in relation to glioma risk.

Dr. Kitahara received her M.H.S. and Ph.D. in cancer epidemiology from the Johns Hopkins Bloomberg School of Public Health. She conducted her doctoral and postdoctoral work in REB and was promoted to research fellow in 2011.

Read other articles in the Summer 2015 issue of Linkage newsletter.