Loss of Basal Cell Character in Regenerating Oral Squamous Epithelium with Altered Expression of Desmoglein 1, Desmocollin 3 and Keratin 19

To clarify the phenotypic changes of basal cells of oral squamous epithelium during pathological regeneration, 40 cases diagnosed as mucous cyst and 10 cases including normal epithelium were used as experimental and control subjects. Antibodies against desmoglein 1 (DSG1), desmocollin 3 (DSC3), keratin 19 (K19) and Ki-67 nuclear antigen (Ki-67) were used for immunohistochemical examinations. Ki-67 index values and the combinations of DSG1. DSC3 and K19 reactivity were analyzed using hierarchical clustering and one-way ANOVA. In contrast to the controls, experimental specimens showed DSG1 positive, DSC3 negative and K19 negative, in 50%, 10% and 87.5% of the experiments, respectively. Cluster hierarchy analysis divided all samples including controls and experiments into three clusters mostly demonstrating DSG1+/DSC3+/K19-, DSG1-/DSC3 +/-/K19+ and DSG1-/DSC3+/K19- as clusters 1, 2 and 3, respectively. Cluster 1 showed significantly higher values of Ki-67 than did cluster 3. The value of DSG1 positive was statistically significant compared with that of DSG1 negative. Our results show that the alteration from DSG1 negative to DSG1 positive could be crucial for cell proliferation, accompanied by K19-loss, which is consistent with the effects of regulatory molecules such as SIRT2 or EphA2 following EGFR-upregulation. We have to be aware that the loss of basal cell character with DSG1 and K19 alterations are basic phenomena in pathological regeneration, and abnormal DSC3-loss infrequently occurs in non-neoplastic conditions.