MORPHOMETRIC STUDY OF NUCLEOLAR ORGANIZER REGIONS (AGNOR) IN HPV-ASSOCIATED PRECANCEROUS LESIONS AND MICROINVASIVE CARCINOMA OF THE ORAL CAVITY

A morphometric study of silver-stained nucleolar organiser regions (NO R) was performed on histological sections from routinely paraffin-embe dded blocks of 26 oral biopsy specimens (21 cases of leukoplakia consi sting of 13 low, 4 moderate, 4 severe degree of dysplasia, and 5 cases of microinvasive carcinomas). In situ hybridisation (ISH) for HPV-DNA was performed on serial sections of the same samples. The following p arameters were studied: V NOR (single AgNOR volume per nucleus), TV NO R (total AgNOR volume per nucleus), and R.I. (AgNOR's roundness index) . The results highlight that not all the morphometric features of AgNO Rs allow the discrimination between lesions with dysplasia of low, mod erate and severe degree and microinvasive carcinoma. TV NOR appeared u seful, while the other morphometric parameters appeared statistically not significant in differentiating between the different lesions. Thes e findings suggest that high values of TV NOR in oral dysplasia could represent a risk marker, identifying a subgroup of lesions with a wors e prognosis, constituting then a possible indication for rigorous clin ical management and/or for complex treatment of these HPV-associated p reneoplastic lesions. (C) 1997 Elsevier Science Ltd.