No abstract

Primary oral melanoma (POM) is an uncommon malignant tumor that originates from the proliferation of melanocytes. Such tumors can be present at any location in the oral cavity; however, it affects more frequently the hard palate and the maxillary alveolar mucosa. POM is usually asymptomatic in the early stages and it presents normally as a pigmented patch or as a mass with a rapid growth rate. In the advanced stages, it can show ulceration, swelling, bleeding, rapid enlargement and loosening of teeth. Melanoma of the mouth is rare, most commonly occurring in the upper jaw of patients more than 65 years. Because of a frequent delay in diagnosis, the tumors are often diagnosed when they are deeper than the average cutaneous melanoma. The prognosis is extremely poor, especially in advanced stages. Therefore, pigmented lesions of undetermined origin should be routinely subjected to a biopsy examination. In this study, we aimed to present a review on primary malignancy.

Aphthous ulcers are the most common oral mucosal lesions in the general population. These often are recurrent and periodic lesions that cause clinically significant morbidity. Many suggestions have been proposed but the etiology of recurrent aphthous stomatitis (RAS) is unknown. Several precipitating factors for aphthous ulcers appear to operate in subjects with genetic predisposition. An autoimmune or hypersensitivity mechanism is widely considered possible. Sometimes aphthous ulcers can be the sign of systemic diseases, so it is essential to establish a correct diagnosis to determine suitable therapy. Before initiating medications for aphthous lesions, clinicians should determine whether well-recognized causes are contributing to the disease and these factors should be corrected. Various treatment modalities are used, but no therapy is definitive. Topical medications, such as antimicrobial mouth-washes and topical corticosteroids (dexamethasone, triamcinolone, fluocinonide, or clobetasol), can achieve the primary goal to reduce pain and to improve healing time but do not improve recurrence or remission rates. Systemic medications can be tried if topical therapy is ineffective.

We know that the Yin Yang 1 protein (YY1) overexpression is positively and strongly correlated with the degree of malignancy of bone tumors. Therefore, we questioned whether we could influence cell invasiveness by deleting YY1 in human osteosarcoma cells (SaOs-2), as tested in Matrigel-coated filters and metastasis implantation of such osteosarcoma cells in vivo, by serial analysis with nuclear magnetic resonance. Moreover, we focused our work on the chemokine receptor CXCR4 and its inhibition by T22 antibody, as well as on systemic (direct in vivo assay) and computer-assisted imaging of angiogenesis-related metastasis. Results showed that cell invasiveness and metastasis implantation by wild-type SaOs-2 cells, as evaluated by histology and immunohistochemistry, are associated with up-regulation of CXCR4 expression, which in turn was significantly reduced by T22. In addition, deletion of YY1 (siRNAYY1-SaOs-2) induced a significant decrease of cell invasion and metastasis growth. This phenomenon was associated with decreased vascular endothelial growth factor (VEGF)/angiogenesis and a complex rearrangement of the gene expression profile as evaluated by microarray analysis. In conclusion, YY1 and VEGF/CXCR4 seem to intervene in the pathogenesis of the malignant phenotype of osteosarcoma by acting on cell invasiveness and metastasis growth. [Cancer Res 2008;68(6):1797-808]