Chronic hyperplastic candidiasis (CHC) is commonly diagnosed in the mouth and has previously been associated with cancerous change. McCullough et al (2002) have shown an association between oral yeast carriage and epithelial dysplasia. P53 is a tumor suppressor gene and an apoptosis regulator, which interacts with many other genes, protecting the cell against DNA damage. The objective of this study was to examine markers which have been associated with malignancy, in CHC.
Methods:
Immunohistochemical methods were used to examine the expression of p53 wild type (WT) and mutant (M), MDM2, p21, metallothionein (MT) and proliferating cell nuclear antigen (PCNA) in 41 CHC lesions, 20 candida-infected (CIC) and 11 non-infected control (NIC) tissues. Appropriate positive and negative controls were used. The intensity and proportion of epithelial cells stained was scored. TUNEL was used to examine apoptosis which was correlated with p53 and metallothionein expression. These markers were measured in sites/lesions of CHC which did not show any epithelial dysplasia, or histological signs of malignancy.
Results:
Mutated p53 scores were higher in CHC than in controls. Levels of MDM2 were not elevated. P21was increased in parabasal epithelial cells. CHC lesions showed a similar basal/parabasal MT staining pattern to normal squamous epithelium. PCNA appeared increased in lesions of CHC and CIC, indicating proliferating epithelial cells. Apoptosis was not increased in lesions of CHC, but further study is required and results will be presented.
Conclusion:
The presence of mutated p53 in oral chronic hyperplastic candidiasis suggests that there may be an increased potential for malignant change to occur in the epithelium, above that of normal tissues. Further, these results suggest a non-active wild type 53 (perhaps due to activity of MDM2 in at least some cells) and therefore increased potential for DNA damage. Further investigation and clinical follow up studies are required.