About 2 weeks after your first study visit, you will be asked to return to the clinic. During this visit, you will have another oral exam with both standard and fluorescent light. You will also be asked 3 questions about being enrolled in any tobacco cessation programs. If any PMOL(s) that were found during the first visit are is still present, the study staff will collect a biopsy of the PMOL tissue. The type of biopsy you have will depend on the number of PMOLs you have and their location, size, shape, and appearance. To perform this biopsy, the affected area is removed by cutting it out (possibly completely). Local anesthesia will be used. The biopsied tissue samples will be sent to the laboratory for routine testing. The results of the biopsies will be used to test the accuracy of the 2 oral exams.