Detection of human papillomavirus DNA in an ameloblastoma using the in situ hybridization technique.

HPV type 18 DNA was identified in an intrabony ameloblastoma using radiolabelled in situ hybridization. The viral DNA was found in a verrucous lesion in a cystic area of the tumor. The absence of HPV DNA in other epithelial areas of the ameloblastoma is suggestive of a secondary infection. HPV is not considered to be an etiological factor in the pathogenesis of this ameloblastoma.

Polyoma virus-induced murine odontogenic tumors.

Neonatal mouse pups were injected subcutaneously with polyoma virus to induce odontogenic tumors. This treatment resulted in a spectrum of tumors that arose in organs dependent upon epithelial-mesenchymal interactions for their organogenesis, which included the teeth, salivary glands, thymus, and lacrimal glands. In addition, several odontogenic tumors with a histologic resemblance to ameloblastoma were identified and analyzed with respect to the presence of markers specific for various stages of ameloblast differentiation. Immunodetection analyses of the odontogenic tumors identified fibronectin and laminin, typical of basement membrane organization during early tooth organogenesis. These same tumors failed to express amelogenin, a gene whose expression is limited to differentiated ameloblasts. In contrast, a 47 kDa enamelin-like polypeptide was identified with the use of an antienamelin antibody. These data were interpreted to suggest that the polyoma virus truncated the differentiation pathway for these odontogenic tissues at an early stage of their development and retained the expression of basement membrane components and the enamelin-like polypeptides, yet excluded expression of amelogenin gene products. This observation suggests that polyoma viral transformation may dysregulate odontogenic tissue interactions and produce tumors composed of cells arrested at a specific stage in their development.

Demonstration of human papillomavirus DNA in a peripheral ameloblastoma by in situ hybridization.

The peripheral ameloblastoma (PA) is a rare, extraosseous, odontogenic lesion usually located on the mandibular or maxillary gingiva. It often appears as an asymptomatic, firm, pink-red nodule with occasional secondary involvement of the underlying bone. Although histologically identical to primary intraosseous ameloblastoma, the PA is notably less aggressive in biologic behavior and rarely recurs following conservative treatment. It has a proposed dual histogenesis, while its etiology remains obscure. Several benign oral mucosal lesions have been found to be associated with various types of human papillomavirus (HPV). The following study uses a commercially available HPV DNA in situ hybridization technique to confirm the presence of HPV in a previously reported case of PA. Results were positive for HPV types 16/18 but negative for HPV types 6/11. The implications of these results with regard to etiology are discussed.

Epstein-Barr virus and jaw tumors in North Nigeria.

Nigerian patients with tumors of the jaw were compared with controls in respect of antibodies to the viral capsid antigens of Epstein-Barr Virus (EBV) and of total immunoglobulin levels. Immunoglobulin levels did not differ between patients and controls but increased two weeks postsurgery. Immunoglobulin A (IgA) antibodies to EBV were detected in a small number of patients, and mean titers of IgG antibodies to EBV were lower in the patient group, indicating a lack of association between EBV and tumor formation. An association was noted between the presence of Hepatitis B surface antigen, and depressed antibody titers to EBV in patients with tumors. Of 78 patients studied, 12% were Hepatitis B surface antigen positive.

Rapid bone regeneration subsequent to subtotal mandibulectomy. Report of an unusual case.

An unusual case of rapid bone regeneration after resection of a large portion of the mandible is presented. The possible factors responsible for the bone regeneration are discussed, with emphasis on the age of the patient, preservation of the periosteum, and infection.