My original studies for the first 8 years of my career were on DNA tumor virus models, first to study gene expression regulation and second to understand carcinogenesis. I have extensive experience with mouse models of liver cancer and rat and hamster models of head and neck cancer. For some time, For the last 10 years the focus has been oral cancer. The major area of this focus is the development of noninvasive techniques for gene expression analysis of oral squamous cell carcinoma (OSCC). We have applied this technology to measurement of changes in oral epithelium miRNA expression after long term polyphenol consumption. This work led to our idea that oral bacteria play a role in the cellular response to green tea polyphenols. Most recently we used measurement of microbiota at two cancer prone sites in marijuana (MJ) users to gain insight into how usage of this drug may change oral mucosa. Current interests are in determining the role of oral microbiome interactions with oral mucosa in the formation and progression of oral and pharyngeal epithelium to squamous cell carcinoma.