Matrix metalloproteinase-2 matrix metalloproteinase-9 and inducible nitric oxide synthase in oral leukoplakia: immunohistochemistry and RT-PCR analysis.

Oral leukoplakia is the most common and potentially malignant disorder of the oral mucosa. The definition of leukoplakia given by the World Health Organization is ?a white plaque that cannot be characterized either from a clinical or from a histopathological point of view?, thus the diagnosis of leukoplakia is based on the exclusion of other lesions of the oral mucosa. We believe it is necessary to identify molecular and immunohistochemical parameters that can contribute to discriminating between the different leukoplakia clinical subtypes coded by the epidemiology. In the present work we show the preliminary results of this research project. We investigated the expression of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9) and inducible nitric oxide synthase (iNOS) in a verrucous proliferative leukoplakia sample. By immunohistochemistry we detected the presence of all the three proteins both in the leukoplakia samples and in healthy oral mucosa, while the reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed in both samples only the expression of MMP-2 and MMP-9 but not iNOS.