 For this study an Oral Premalignant Lesions OPL is defined as a lesion which can include atypical hyperplasia, atypical hyperkeratosis, leukoplakia, and erythroplakiaerythro-leukoplakia. Histology MUST be confirmed by an MSKCC pathologist for all participating sites. An OPL may be located in the oral cavity, oropharynx. 