My research has focused on histopathologic features of nonalcoholic fatty liver disease, specifically, grading and staging the lesions of this significant disease, and its findings with other forms of chronic liver disease. I have worked to help define essential lesions necessary for the definition/diagnosis of nonalcoholic steatohepatitis, as well as the unique types of fibrosis that occur in this entity. I was co-chair of the pathology committee of the NIH sponsored NASH Clinical Research Network, was a co-author for the scoring system most often utilized for clinical treatment trials for NASH worldwide, and have participated in NIH-sponsored therapeutic interventional trials of NASH; I was also a member of pathology committees for NIH-sponsored studies for treatment of HCV and HBV. I have participated as the pathology representative for publication of Practice Guidance for NASH for the AASLD. I recently worked with a large group of international pathologists as the lead author to define a working terminology for an unusual form of primary liver cancer in order for reproducible epidemiologic, clinical and molecular studies to occur.