Dr. Mary Helen Barcellos-Hoff received her undergraduate degree from the University of Chicago and earned a doctorate in experimental pathology from the University of California, San Francisco, where she is currently Professor,  Wun-Kon Fu Endowed Chair, and Vice Chair of Research in Radiation Oncology.  She leads a laboratory that investigates the effects of ionizing radiation as a carcinogen and as a therapeutic. She discovered that radiation activates transforming growth factor β (TGFβ), which is a major signal in irradiated tissues and tumors.  Dr. Barcellos-Hoff studies cell and tissue interactions that modulate mammary carcinogenesis using a unique mouse model to evaluate the effects of non-targeted radiation effects, which has identified radiation-induced TGFβ and systemic inflammation as a major contributor to the development of more aggressive breast cancer in irradiated women and mice. She also discovered that TGFβ is a critical regulator of DNA damage response, a cell survival factor in innate immunity, and a mechanism of radiotherapy and immunotherapy resistance. These findings have important implications for patient stratification and strategic use of therapies that block TGFβ.

She led NASA program projects and research into heavy charged particle and low dose radiation effects for two decades.  She is currently funded by the National Cancer Institute and biopharma to study inflammation and anti-tumor immunity in carcinogenesis and radiotherapy respectively.