AHRR and oral cavity squamous cell carcinoma: To investigate a potential role of smoking-induced CYP1B1 and AHRR hypomethylation in the development of oral cancer, we compared the methylation data from our healthy never smokers with the TCGA data for 16 oral squamous cell carcinoma (OSCC) biopsies that were specified as “gum” or “palate”, similar to the samples used in our EWAS.