Expression of proliferating cell nuclear antigen (PCNA) in oral submucous fibrosis, oral epithelial hyperkeratosis and oral epithelial dysplasia in Taiwan

To test whether the oral epithelia of oral submucous fibrosis (OSF), epithe lial hyperkeratosis (EH) and epithelial dysplasia (ED) may have increased p roliferative activity under the long-term exposure to areca quid ingredient s and whether there is an increased expression of proliferating cell nuclea r antigen (PCNA) in oral premalignant lesions with disease progression, we used an immunohistochemical technique with the mouse monoclonal antibody PC 10 to investigate PCNA expression in histologic sections of OSF, EH, ED and normal oral mucosa (NOM). Positive PCNA staining was found mainly in basal and parabasal epithelial cells in all specimens of OSF, EH, ED and NOM. Th e mean PCNA labeling indices (LI) in NOM, OSF, EH and ED were 8.8 +/- 2.7%, 22.1 +/- 12.5%. 25.5 +/- 5.2% and 44.9 +/- 15.4%, respectively. Significan t differences in the PCNA LI were noted between NOM and OSF (P < 0.01), EH (P < 0.001) or ED (P < 0.001), as well as between ED and OSF (P < 0.001) or EH (P < 0.01). The gradual increase of PCNA expression with the morphologi c transformation of normal epithelial cells into dysplastic epithelial cell s suggests that there is increased proliferative activity in oral premalign ant lesions with disease progression. However, no significant correlation w as found between PCNA LI in OSF epithelium and the: clinicohistologic param eters of OSF. In addition, the mean PCNA LI of p53-positive OSF cases (23.7 +/- 12.0%) was very close to that of p53-negative OSF cases (23.9 +/- 13.1 %), suggesting that there was no association between PCNA and p53 expressio n in OSF. (C) 2000 Elsevier Science Ltd. All rights reserved.