Background: The major function of Malassez's epithelial rest (ERM) cells is thought to be maintenance of the homeostasis of the periodontal ligament. The purpose of this study was to investigate the effect of aging on the functions of ERM cells in vitro. Methods: ERM cells cultured from porcine teeth were used in this study, and cells at passages 3, 11 and 17 were analyzed by DNA microarray to evaluate gene expression profiles. Furthermore, quantitative real-time RT-PCR was performed to confirm the microarray data for selected genes. Results: The microarray data revealed that approximately 4,300 of the 21,123 genes on the array were expressed at significantly different levels. Among them, 230 genes, including BMP2, were significantly decreased between the 3rd to the 11th passage. Moreover, 23 genes, including beta-defensin1, MMP13 and CD61, were significantly down-regulated from the 3rd to the 11th and from the 11th to the 17th passages(P<0.05). Conclusion: These results suggest that cementogenesis, antibacterial effects, collagenase activity and cell adhesive functions of the ERM are affected by aging.

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Background: CD44, a family of alternatively spliced transmembrane cell adhesion molecules, is expressed in many types of tumors, including oral squamous cell carcinoma. CD44 variant 3 and 6 (CD44v3 and CD44v6) expression in head and neck squamous cell carcinoma has been suggested to correlate with a poor prognosis. We investigated the relationship between CD44 variant forms and clinicopathological parameters in oral squamous cell carcinoma of the tongue (OSCCT). Methods: Immunohistochemical analysis of 60 cases of OSCCT was performed to investigate the relationship of CD44v3 and CD44v6 expression with clinicopathological parameters and clinical outcome. Results: Significant correlations were present between CD44v3 expression and clinicopathological parameters, such as mode of invasion (P<0.0001), differentiation type (P<0.0001), local recurrence (P<0.05), and secondary metastasis to lymph nodes (P<0.05). Loss of staining of CD44v3 also significantly correlated with a poor prognosis (P<0.001). On the other hand, CD44v6 expression showed no correlation with clinicopathological parameters. Conclusion: CD44v3 may be useful as a diagnostic/prognostic biomarker of OSCCT because low CD44v3 immunoreactivity is associated with high invasive potential and poor prognosis.

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Carcinoma cuniculatum (CC) has been regarded as a well differentiated subtype of oral squamous cell carcinoma (SCC) that is characterized by keratin cores and keratin-filled crypts, but lacking obvious cytological malignancy. There have been relatively few case reports of oral CC, and descriptions of the long-term prognosis are scarce. In addition, the process of change from CC to conventional SCC is still poorly understood. In 1983, an 80-year-old woman admitted for a white spot underwent an excision biopsy, and CC was diagnosed. This lesion then recurred in 1993, with the same diagnosis, but it changed into conventional SCC when it recurred in 1994. Tissue materials from the three surgical treatments were examined with hematoxylin and eosin stain as well as with immunohistochemical stains for Ki-67 and for p53 and p63 gene products (P53, P63). While expressions of P53 protein and Ki-67 became stronger with every recurrence, the opposite tendency was obtained for P63 expression. This is the first report to describe a case of long-term follow-up of CC in which the expression modes of oncogene products were analyzed.

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Basaloid squamous cell carcinoma (BSCC) is a rare distinct variant of squamous cell carcinoma. We report a case of basaloid squamous cell carcinoma of the tongue in a 76-year-old Japanese man. The initial clinical examinations revealed a 23 × 25 × 15 mm reddish ulcerated mass with an elastic hard texture at the left lateral border of the tongue. The histopathological findings revealed invasive growth of basaloid epithelial tumor cells that formed nests in the subepithelial layer to the muscle layer. Immunohistochemically, the tumor was positive for p63 protein and had a high Ki-67 labeling index of more than 70% in parts. The patient underwent chemotherapy involving super-selective intra-arterial administration of carboplatin and local irradiation, followed by a subtotal tongue resection. The patient has been followed for 48 months postoperatively without any evidence of disease. The super-selective intra-arterial chemotherapy is a feasible and important application in treating BSCC of the tongue showing aggressive biological behavior.

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