Malignant transformation of oral lichen planus

We present fivepatients with squamous cell carcinoma of the buccal mucosa arised on the pre-existing oral lichen planus. Immunohistochemical analysis of the precursor lesions was performed by using p53 and Ki-67 antigens, and compared with the unaffected mucosa of the same patient, as well as with the matched control patient's mucosa. Clinical diagnosis of OLP has to be confirmed by histopathological analysis. As a premalignant lesion, OLP need to be assessed by use of immunohistochemical and genetic markers as well. Further research is essential for better understanding of the mechanisms and propensity of some OLP lesions to undergo malignant transformation.