Dental professionals are trained to notice any abnormal looking areas of the mouth. This could be a lump that develops on the gum or cheeks or something that is off in color to surrounding tissues. It could also be an ulcer that does not seem to go away. A biopsy procedure can be used to sample the area of concern. An excisional biopsy removes all suspected tissue while an incisional biopsy removed only a part. In either case, those samples are sent to an oral pathology laboratory so that a pathologist specially trained in looking at diseases that affect the head and neck and mouth can look under the microscope and give an accurate diagnosis or at least rule out any serious problems.