Immunohistochemical expression levels of cyclin D1 and CREPT reflect the course and prognosis in oral precancerous lesions and squamous cell carcinoma.

Cyclin D1 is the most essential progressive regulator of the cell cycle, and its transcription is enhanced by CREPT (cell cycle-related and expression-elevated protein in tumour). These molecules regulate cell growth, and their aberrant expression can cause malignant transformation. In this study, the expression of these molecules was explored to investigate the molecular alterations in oral precancerous lesions and squamous cell carcinoma. Cyclin D1 and CREPT expression was examined immunohistochemically in tissue specimens from 55 patients with oral epithelial precursor lesions (OEPLs) and 84 patients with oral squamous cell carcinoma (OSCC). Associations between the results and clinicopathological variables were examined. Cyclin D1 and CREPT expression levels were higher in OSCC than in OEPLs. Furthermore, there were statistically significant differences in cyclin D1 expression among the different grades of OEPLs and OSCC lesions. In OSCC, there were statistically significant differences in CREPT expression according to sex, T stage, and degree of differentiation. In addition, the expression of both molecules was significantly correlated with postoperative metastasis and modes of invasion. The expression of cyclin D1 and CREPT was found to depend upon the state of development and progression of the oral epithelial lesions, and clinicopathological behaviours might be affected by these molecules in OSCC.

Regulatory T cells and M2-polarized tumour-associated macrophages are associated with the oncogenesis and progression of oral squamous cell carcinoma.

Regulatory T cells (Tregs) and tumour-associated macrophages (TAMs) contribute to the tumour microenvironment by inhibiting anti-tumour immune responses. This study was performed to investigate the roles of Tregs and TAMs in oral squamous cell carcinoma (OSCC) and oral epithelial precursor lesions (OEPL). The expression of Treg markers CD25 and FoxP3 and TAM markers CD163 and CD204 was investigated in 82 OSCC and 45 OEPL specimens, and their associations with clinicopathological parameters were analyzed. Correlations were found among CD25, FoxP3, CD163, and CD204 levels (P < 0.001), and these targets were up-regulated in OSCC compared to OEPL (P < 0.001). In OSCC, infiltration of Tregs and/or M2 TAMs was associated with sex and clinicopathological features, such as tumour size, nodal metastasis, tissue differentiation, stromal reaction, invasive behaviour, and invasive depth. In OEPL, CD25, FoxP3, CD163, and CD204 immunoreactivities were significantly associated with sex, postoperative recurrence, and cancerization to OSCC. This study is novel in showing that the infiltration of Tregs and M2 TAMs is significantly associated with the progression of premalignant lesions to OSCC. This suggests that these cells represent prognostic biomarkers for premalignant lesion progression and that immunotherapeutic approaches to control Treg/M2 TAM numbers could protect against progression to malignancy.

Experimental comparison between tractional and compressive stress on temporomandibular joint.

OBJECTIVE: We experimentally compared the effects of compressive and tractional mechanical stress on the temporomandibular joint (TMJ) of rabbits to assess the etiology of progressive condylar resorption. MATERIALS AND METHODS: We performed a cortical osteotomy using custom-made devices that were lengthened by 0.25 mm every 12 h for 1 week after surgery. During this time, the rabbit TMJ was under compressive or tractional mechanical stress. The samples in each group were examined using micro-computed tomography and histological staining. RESULTS: Scores for the area of bone resorption were higher in the compressive group than in the tractional group. Moreover, scores for the depth of bone resorption were higher in the compressive group than those in the tractional group. We observed a significantly higher prevalence of resorption in the subcondylar bone in the compressive group than in the tractional group. There were substantially more cells that were positive for tartrate-resistant acid phosphatase in the compressive group than in the control and tractional groups. CONCLUSIONS: The outcomes here suggest that excessive mechanical stress, particularly compressive mechanical stress, may significantly affect morphological bone change findings in the TMJ.

Diagnostic performance of MR imaging of three major salivary glands for Sjögren's syndrome.

OBJECTIVE: We analyzed the diagnostic performance of the MR imaging findings of the parotid, submandibular, and sublingual glands to discriminate between patients with and without Sjögren's syndrome. METHODS: We retrospectively analyzed the correlation between the MR imaging and histopathological findings obtained from 69 patients with clinically suspected Sjögren's syndrome. We evaluated the heterogeneous signal intensity distribution on T1- and T2-weighted images, the multiple high-signal-intensity spots on MR sialograms, and the volume of the parotid, submandibular, and sublingual salivary glands. RESULTS: The multiple high-signal-intensity spots in the parotid gland showed the highest sensitivity and diagnostic accuracy (82% and 83%, respectively). In addition, the multiple high-signal-intensity spots and the heterogeneous signal intensity distribution in the submandibular gland showed high specificity (100% and 88%, respectively). The volume of the submandibular gland, but not that of the parotid or sublingual gland, was smaller in patients with Sjögren's syndrome. CONCLUSIONS: The presence of multiple high-signal-intensity spots on an MR sialogram in the parotid gland should be considered the best diagnostic indicator for Sjögren's syndrome. The presence of spots, heterogeneity, and the change to smaller volumes in the submandibular gland were also helpful because of their high specificity, particularly in advanced cases.

Carcinoembryonic antigen-related cell adhesion molecules as surrogate markers for EGFR inhibitor sensitivity in human lung adenocarcinoma.

BACKGROUND: Lung adenocarcinoma (LADCA) patients with epidermal growth factor receptor (EGFR) mutations are in general associated with relatively high clinical response rate to EGFR-tyrosine kinase inhibitors (TKIs) but not all responded to TKI. It has therefore become important to identify the additional surrogate markers regarding EGFR-TKI sensitivity. METHODS: We first examined the effects of EGFR-TKIs, gefitinib and erlotinib, upon cell proliferation of lung adenocarcinoma cell lines. We then evaluated the gene profiles related to EGFR-TKI sensitivity using a microarray analysis. Results of microarray analysis led us to focus on carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family, CEACAM 3, 5, 6, 7, and 19, as potential further surrogate markers of EGFR-TKI sensitivity. We then examined the correlation between the status of CEACAM 3, 5, 6, 7, and 19 immunoreactivity in LADCA and clinicopathological parameters of individual cases. RESULTS: In the cases with EGFR mutations, the status of all CEACAMs examined was significantly higher than that in EGFR wild-type patients, but there were no significant differences in the status of CEACAMs between TKI responder and nonresponder among 22 patients who received gefitinib therapy. However, among 115 EGFR mutation-negative LADCA patients, both CEACAM6 and CEACAM3 were significantly associated with adverse clinical outcome (CEACAM6) and better clinical outcome (CEACAM3). CONCLUSION: CEACAMs examined in this study could be related to the presence of EGFR mutation in adenocarcinoma cells but not represent the effective surrogate marker of EGFR-TKI in LADCA patients. However, immunohistochemical evaluation of CEACAM3/6 in LADCA patients could provide important information on their clinical outcome.

Immunohistochemical detection of BH3-only proteins in ameloblastic tumors.

OBJECTIVE: To evaluate expression of BH3-only proteins in odontogenic tumors, expression of Bid, Bim, Bad, Noxa, and Puma was analyzed in ameloblastic tumors as well as in tooth germs. METHODS: Nine tooth germs, 37 ameloblastomas, and five malignant ameloblastic tumors were examined immunohistochemically with antibodies against Bid, Bim, Bad, Noxa, and Puma. RESULTS: Immunohistochemical reactivity for Bid, Bim, Bad, Noxa, and Puma was detected in the cytoplasm of cellular components in normal and neoplastic odontogenic tissues. Expression of these BH3-only proteins was evident in odontogenic epithelial cells near the basement membrane in tooth germs and ameloblastic tumors. Acanthomatous ameloblastomas showed no reactivity for Bid, Bim, Bad, Noxa, or Puma in keratinizing cells, whereas granular cells in granular cell ameloblastomas reacted with these BH3-only proteins. Basal and desmoplastic ameloblastomas and ameloblastic carcinomas showed immunoreactivity for the BH3-only proteins in most neoplastic cells. CONCLUSION: Expression of Bid, Bim, Bad, Noxa, and Puma in tooth germs and ameloblastic tumors suggests that the BH3-only proteins have a role in apoptotic cell death of normal and neoplastic odontogenic epithelium. Distinctive expression patterns of these BH3-only proteins in ameloblastoma variants suggest that the BH3-only proteins might be involved in tumor cell differentiation of ameloblastomas.

Immunohistochemical detection of phosphorylated JNK, p38 MAPK, and ERK5 in ameloblastic tumors.

BACKGROUND: To evaluate roles of mitogen-activated protein kinases (MAPKs) in oncogenesis and cytodifferentiation of odontogenic tumors, expression of phosphorylated JNK (p-JNK), p38 MAPK (p-p38 MAPK), and ERK5 (p-ERK5) was analyzed in ameloblastic tumors as well as in tooth germs. METHODS: Ten tooth germs, 47 ameloblastomas, and 5 malignant ameloblastic tumors were examined immunohistochemically with the antibodies against p-JNK, p-p38 MAPK, and p-ERK5. RESULTS: Immunoreactivity for p-JNK was detected in epithelial or neoplastic cells detached from the basement membrane in 7 tooth germs and 7 ameloblastomas, and the expression levels of p-JNK in ameloblastic tumors were significantly lower than that in tooth germs. Expression of p-p38 MAPK was found in epithelial or neoplastic cells in tooth germs and ameloblastic tumors except for two ameloblastomas, and increased expression was found in keratinizing cells of acanthomatous ameloblastomas. The expression level of p-p38 MAPK in ameloblastomas was significantly higher than the levels in tooth germs and malignant ameloblastic tumors. Immunoreactivity for p-ERK5 was found predominantly in epithelial or neoplastic cells near the basement membrane in tooth germs and ameloblastic tumors. The expression levels of p-ERK5 in ameloblastic tumors were slightly higher than that in tooth germs, and plexiform ameloblastomas showed significantly higher p-ERK5 expression than follicular ameloblastomas. CONCLUSION: Expression of p-JNK, p-p38 MAPK, and p-ERK5 in tooth germs and ameloblastic tumors suggests that these MAPK signaling pathways contribute to cell proliferation, differentiation, or apoptosis in both normal and neoplastic odontogenic tissues. Altered expression of these phosphorylated MAPKs in ameloblastic tumors may be involved in oncogenesis and tumor cell differentiation.

Immunohistochemical detection of uPA, uPAR, PAI-1, and maspin in ameloblastic tumors.

BACKGROUND: To evaluate the roles of extracellular matrix (ECM)-degrading serine proteinase in progression of odontogenic tumors, expression of urokinase-type plasminogen activator (uPA), uPA receptor (uPAR), plasminogen activator inhibitor-1 (PAI-1), and maspin was analyzed in ameloblastic tumors as well as in tooth germs. METHODS: Tissue specimens of 10 tooth germs, 45 ameloblastomas, and 5 malignant ameloblastic tumors were examined immunohistochemically with the use of antibodies against uPA, uPAR, PAI-1, and maspin. RESULTS: Immunohistochemical reactivity for uPA, uPAR, PAI-1, and maspin was detected in normal and neoplastic odontogenic tissues: uPA was recognized predominantly in mesenchymal cells, uPAR was evident in epithelial cells, PAI-1 was found in both epithelial and mesenchymal cells, and maspin was expressed only in epithelial cells. The levels of uPA and uPAR immunoreactivity in ameloblastic tumors were slightly higher than the levels in tooth germs, while PAI-1 reactivity in ameloblastomas tended to be lower than that in tooth germs. The level of maspin immunoreactivity in ameloblastomas was significantly higher than that in tooth germs, and ameloblastic carcinoma showed decreased maspin reactivity. CONCLUSION: Expression of uPA, uPAR, PAI-1, and maspin in tooth germs and ameloblastic tumors suggests that interactions among these molecules contribute to ECM degradation and cell migration during tooth development and tumor progression. Altered expression of the serine proteinase and its associated molecules in ameloblastic tumors may be involved in oncogenesis of odontogenic epithelium.

Immunohistochemical detection of insulin-like growth factors, platelet-derived growth factor, and their receptors in ameloblastic tumors.

BACKGROUND: To evaluate the roles of growth factors in oncogenesis and cytodifferentiation of odontogenic tumors, expression of insulin-like growth factors (IGFs), platelet-derived growth factor (PDGF), and their receptors was analyzed in ameloblastic tumors as well as in tooth germs. METHODS: Tissue specimens of 10 tooth germs, 47 ameloblastomas, and five malignant ameloblastic tumors were examined immunohistochemically with the use of antibodies against IGF-I, IGF-II, IGF-I receptor (IGF-IR), PDGF A-chain, PDGF B-chain, PDGF alpha-receptor, and PDGF beta-receptor. RESULTS: Immunohistochemical reactivity for IGFs, PDGF chains, and their receptors was detected predominantly in odontogenic epithelial cells near the basement membrane in tooth germs and in benign and malignant ameloblastic tumors. The expression levels of IGF-II and PDGF chains were significantly higher in ameloblastic tumors than in tooth germs. Malignant ameloblastic tumors showed higher reactivity for PDGF chains than benign ameloblastomas and higher reactivity for platelet-derived growth factor receptors than tooth germs. The expression levels of PDGF chains were significantly higher in follicular ameloblastomas than in plexiform ameloblastomas. Desmoplastic ameloblastomas showed higher expression of IGFs and IGF-IR when compared with other ameloblastoma subtypes. CONCLUSION: Expression of IGFs, PDGF, and their receptors in tooth germs and ameloblastic tumors suggests that these growth factor signals contribute to cell proliferation or survival in both normal and neoplastic odontogenic tissues. Expression of these molecules in odontogenic tissues possibly affects interactions with the bone microenvironment during tooth development and intraosseous progression of ameloblastic tumors. Altered expression of the ligands and receptors in ameloblastic tumors may be involved in oncogenesis, malignant potential, and tumor cell differentiation.

Immunohistochemical detection of MT1-MMP, RECK, and EMMPRIN in ameloblastic tumors.

BACKGROUND: To evaluate the roles of matrix-degrading proteinase regulators in progression of odontogenic tumors, expression of membrane-bound matrix metalloproteinase (MMP) MT1-MMP, MMP inhibitor RECK and MMP inducer EMMPRIN was analyzed in ameloblastic tumors as well as in tooth germs. METHODS: Tissue specimens of 11 tooth germs, 40 ameloblastomas, and five malignant ameloblastic tumors were examined immunohistochemically with the use of antibodies against MT1-MMP, RECK, and EMMPRIN. RESULTS: Immunohistochemical reactivity for MT1-MMP, RECK and EMMPRIN was detected predominantly in odontogenic epithelial cells near the basement membrane in tooth germs and benign and malignant ameloblastic tumors. The level of immunoreactivity for MT1-MMP was slightly higher in benign and malignant ameloblastic tumors than in tooth germs. RECK expression was lower in ameloblastomas than in tooth germs. Follicular ameloblastomas showed significantly lower expression of RECK than plexiform ameloblastomas, and immunoreactivity for RECK in acanthomatous ameloblastomas was slightly lower than that in other cellular variants. CONCLUSION: Expression of MT1-MMP, RECK and EMMPRIN in tooth germs and ameloblastic tumors suggests that these normal and neoplastic epithelial components control MMP-dependent extracellular matrix (ECM) degradation during tooth development and tumor progression via epithelial-mesenchymal interactions.

Expression of bone morphogenetic proteins and their associated molecules in ameloblastomas and adenomatoid odontogenic tumors.

OBJECTIVE: To further clarify the roles of regulators of embryonic development, bone morphogenetic protein (BMPs) and their associated molecules, in oncogenesis and cytodifferentiation of odontogenic tumors, the expression of these regulator molecules were analyzed in epithelial odontogenic tumors as well as in tooth germs. MATERIALS AND METHODS: Tooth germs, ameloblastomas, adenomatoid odontogenic tumors, and malignant ameloblastomas were examined by RT-PCR and immunohistochemistry for detection of BMP-2, -4, -7, BMP receptors I and II (BMPR-I, BMPR-II), core-binding factor alpha1 (CBFA1), and osterix. RESULTS: mRNA expression of BMPs, BMPRs, CBFA1, and osterix was detected in all odontogenic tissues. Immunohistochemical reactivity for BMPs, BMPRs, and CBFA1 was detected in both epithelial and mesenchymal cells of tooth germs and epithelial odontogenic tumors. BMPs and BMPRs were evidently expressed in odontogenic epithelial cells in tooth germs and epithelial odontogenic tumors. Acanthomatous ameloblastomas showed increased BMP-7 reactivity in keratinizing cells. Nuclear CBFA1 expression was detected scatteredly in odontogenic epithelial cells in normal and neoplastic odontogenic tissues, as well as in some mesenchymal cells in tooth germs and in some stromal cells in epithelial odontogenic tumors. Ameloblastic carcinomas showed low reactivity for BMPs, BMPRs, and CBFA1. CONCLUSION: BMPs and their associated molecules might play a role in cytodifferentiation of normal and neoplastic odontogenic epithelium via epithelial-mesenchymal interactions.

Molecular pathology of odontogenic tumors.

Odontogenic tumors are lesions derived from the elements of the tooth-forming apparatus and are found exclusively within the jawbones. This review represents a contemporary outline of our current understanding of the molecular and genetic alterations associated with the development and progression of odontogenic tumors, including oncogenes, tumor-suppressor genes, oncoviruses, growth factors, telomerase, cell cycle regulators, apoptosis-related factors, regulators of tooth development, hard tissue-related proteins, cell adhesion molecules, matrix-degrading proteinases, angiogenic factors, and osteolytic cytokines. It is hoped that better understanding of related molecular mechanisms will help to predict the course of odontogenic tumors and lead to the development of new therapeutic concepts for their management.

Immunohistochemical detection of beta-catenin and adenomatous polyposis coli in ameloblastomas.

BACKGROUND: To clarify the roles of the Wnt signaling pathway in oncogenesis and cytodifferentiation of odontogenic tumors, expression of beta-catenin and adenomatous polyposis coli (APC) was analyzed in ameloblastomas as well as in tooth germs. METHODS: Tissue specimens of 10 tooth germs, 40 benign ameloblastomas, and five malignant ameloblastomas were examined immunohistochemically with the use of antibodies against beta-catenin and APC. RESULTS: Immunohistochemical reactivity for beta-catenin was detected in the cell membrane and cytoplasm of most odontogenic epithelial cells in tooth germs and ameloblastomas. Nuclear beta-catenin expression was recognized in nine of 40 ameloblastomas and two of five malignant ameloblastomas, but not in tooth germs. APC was evidently expressed in odontogenic epithelial cells neighboring the basement membrane in tooth germs and ameloblastomas, and the reactivity was significantly lower in benign and malignant ameloblastomas than in tooth germs. Follicular ameloblastomas and acanthomatous ameloblastomas tended to show high nuclear beta-catenin expression and low APC reactivity, as compared with other ameloblastoma variants. CONCLUSION: Expression of beta-catenin and APC in tooth germs and ameloblastomas suggests that aberration of the Wnt signaling pathway might play a role in oncogenesis and cytodifferentiation of odontogenic epithelium via deregulation of cell proliferation.

Immunohistochemical analysis of apoptosis-related factors in lining epithelium of radicular cysts.

BACKGROUND: Some studies suggest that apoptosis-related factors are involved in the inflammatory processes of marginal periodontal lesions. However, the role of apoptosis in periapical inflammatory lesions remains unclear. We investigated the possible role of apoptotic cell death in periapical inflammatory lesions by means of immunohistochemical analysis of apoptosis-related factors and use of a cell proliferation marker. METHODS: Paraffin-embedded sections of 19 radicular cysts (RCs), and five residual radicular cysts (RRCs) and control specimens of normal gingivae excised from seven cadavers were prepared and examined immunohistochemically with the use of monoclonal antibodies or polyclonal antisera against single-stranded DNA (ssDNA), p53, Bax, Bcl-2, caspase-3, Fas, Fas ligand (Fas-L), and Ki-67 antigen. RESULTS: Epithelium of gingiva, RCs, and RRCs showed expression of ssDNA in suprabasal and superficial epithelial cells and Ki-67 reactivity in basal and parabasal cells. Expression of Ki-67 and ssDNA in RCs and RRCs was slightly higher than that in gingiva. Both Ki-67 and ssDNA reactivity in RCs with intense inflammatory reactions or with thick lining epithelium were significantly stronger than those in RCs with less inflammatory reactions or with thin lining epithelium. Reactivity for p53 was noted sporadically in epithelium of gingiva, RCs, and RRCs, and p53 expression in RCs was significantly greater than that in gingiva. Ki-67 and ssDNA reactivity in RCs increased parallel to the degree of p53 expression. Bax and Bcl-2 were detected in some basal epithelial cells in RCs and RRCs as well as in gingiva. The ssDNA reactivity significantly increased parallel to Bax expression and slightly decreased parallel to Bcl-2 expression in lining epithelium of RCs. Caspase-3 was detected in superficial epithelial cells of both gingiva and lining epithelium of RCs and RRCs, and the distribution of these cells was compatible with the expression of ssDNA. Expression of Ki-67 and ssDNA in caspase-3-positive fields was significantly higher than that in caspase-3-negative fields in RCs. There was very limited expression of Fas and Fas-L in lining epithelium of RCs and RRCs as well as in gingiva. CONCLUSIONS: These data suggest that apoptosis-related factors are involved in the pathophysiologic activity of periapical inflammatory lesions. Such factors may be affected by the structure of lining epithelium and the degree of inflammatory change.

Adenovirus-mediated CTLA4 immunoglobulin G gene therapy in cardiac xenotransplantation.

BACKGROUND: CTLA4 immunoglobulin (CTLA4 Ig), which binds with high affinity to B7-1 and B7-2, interrupts T-cell activation by inhibiting the costimulatory signal. CTLA4Ig has been used to achieve antigen-specific tolerance induction in cardiac allografts. On the other hand, we have shown that short-term administration of deoxyspergualin (DSG) and daily cyclosporine (CsA) induces long-term survival of cardiac xenotransplants. We hypothesized that the combination therapy of DSG and adenovirus-mediated CTLA4IgG might induce long-term, survival or tolerance in cardiac xenotransplantation. OBJECTIVES: Syrian hamster hearts were transplanted heterotopically into Lewis rats. We compared the survival time and immunopathology of the following five groups: (1) no treatment; (2) DSG (5 mg/kg per day intramuscularly [IM], days -1 to +7) alone; (3) CsA (15 mg/kg per day IM, day 0 to rejection) plus DSG; (4) AdexLacZ (LacZ-adenovirus 1 x 10(9) (PFU intravenously [IV], day -7) plus DSG; and (5) AdexCTLA4IgG (CTLA4IgG-adenovirus 1 x 10(9) PFU IV, day -7) plus DSG. RESULTS: The survival times were: (1) no treatment, 3.7 days; (2) DSG alone, 12.4 days; (3) CyA plus DSG, >100 days; (4) AdexLacZ plus DSG, 11.0 days; and (5) AdexCTLA4IgG plus DSG, 23.6 days. Adenovirus-mediated CTLA4IgG therapy with DSG prolonged survival time significantly compared with DSG alone or AdexLacZ plus DSG, but CTLA4IgG therapy was not as effective as CsA. Immunopathology showed the deposition of C3 and IgM on the endothelium in the AdexCTLA4IgG plus DSG group. CONCLUSIONS: We showed that the effectiveness of adenovirus-mediated CTLA4IgG gene therapy in cardiac xenotransplantation in less than that of CsA. Combination therapy with inhibition of the B7/CD28 constimulatory signal and DSG administration might not be sufficient for long-term survival or tolerance in cardiac xenotransplantation.

PTC gene mutations and expression of SHH, PTC, SMO, and GLI-1 in odontogenic keratocysts.

The Patched (PTC) gene is responsible for basal cell nevus syndrome (BCNS) accompanied by multiple odontogenic keratocysts (OKCs), and its product plays a role in the Sonic hedgehog (SHH) signaling pathway involving smoothened (SMO) and GLI-1. To clarify the role of SHH signaling in OKCs, the expression of SHH, PTC, SMO, and GLI-1 and mutations of PTC were examined in 18 sporadic, 4 BCNS-associated OKCs and 7 control gingivae. SHH, PTC, SMO, and GLI-1 were detected in all OKC and gingiva samples by reverse transcriptase-polymerase chain reaction (RT-PCR). Immunoreactivity for SHH and GLI-1 was markedly higher in epithelial components than in subepithelial cells, while immunoreactivity for PTC and SMO was similar in epithelial components and subepithelial cells in OKCs. The positive rate of PTC and SMO expression in subepithelial cells of OKCs was significantly higher than that in gingivae. The positive rate of GLI-1 expression in subepithelial cells of BCNS-associated OKCs was significantly higher than that in primary OKCs. These results suggest that the SHH signaling might be involved in the pathophysiologic nature of OKCs. While mutations of the PTC gene could not be detected in 4 BCNS-associated OKCs by direct DNA sequencing, 3 of 5 primary and 4 of 4 recurrent OKCs had several mutations of this gene. These results suggest that PTC mutations are probably related not only to BCNS-associated OKCs but also to sporadic OKCs.

Sebaceous adenoma in the retromolar region: report of a case with a review of the English literature.

This paper reports a rare case of sebaceous adenoma on the right mandibular retromolar mucosa in a 73-year-old Japanese man, with a review of the English literature of sebaceous adenomas of salivary gland origin. A painless and yellowish polypoid lesion in the retromolar mucosa was histologically a relatively well-circumscribed neoplastic mass composed of well-differentiated sebaceous cells with cystic and duct-like structures, and was considered to be a true sebaceous gland neoplasm arising from the minor salivary gland tissue.

Intramucosal naevus with pseudoepitheliomatous hyperplasia in the gingiva: a case report.

This article describes the unusual case of an intraoral pigmented naevus with pseudoepitheliomatous hyperplasia of the gingiva. A 62-year-old man presented with an almost coal-black pigmented and partly white, spotted, dome-shaped swelling on the lingual gingiva of the mandible. Histologically, the lesion consisted of clusters of round-shaped naevus cells containing melanin granules, reactive with both S-100 immunohistochemical stain and Masson-Fontana silver stain, and pseudoinvasive squamous nests, reactive with cytokeratin. The pathogenesis of the present lesion and problems encountered in its differential diagnosis are discussed.

Histopathological and immunohistochemical analysis of calcifying odontogenic cysts.

METHOD AND RESULTS: Calcifying odontogenic cysts (COCs) were examined histopathologically and immunohistochemically to characterize the histological and cytological properties of these lesions. Histopathologically, COCs showed thin or thick lining epithelium with ghost cells. COCs were classified according to proliferative type or nonproliferative type lining epithelium, the presence or absence of ameloblastomatous appearance, and the presence or absence of odontoma in the cyst walls. Immunohistochemically, amelogenin protein was expressed chiefly in ghost cells, whereas cytokeratin 19 (CK19) and bcl-2 proteins were expressed chiefly in lining epithelial cells. The proportion of cases positive for bcl-2 protein was slightly higher in COCs with odontoma than in those without odontoma. Lining epithelial cells sporadically showed positive reactions for Ki-67 antigen. Mean Ki-67 labeling index was slightly greater in COCs with proliferative type lining epithelium, COCs with ameloblastomatous appearance of the cyst walls, and COCs with odontoma of the cyst walls than in COCs without these histological features. Our results suggest that ghost cells or lining epithelial cells show ameloblastic cytodifferentiation or odontogenic epithelial characteristics, that bcl-2 protein is associated with survival of lining epithelial cells in COCs, and that high proliferation potential is associated with ameloblastomatous proliferation or combined odontoma. COCs exhibited various histological features with several transitional forms, and immunohistochemical examinations revealed little or no difference in cytodifferentiation and cellular activity among COCs. CONCLUSION: We conclude that COCs with various histological features have neoplastic potential and may not be separate entities within the same histological spectrum.

Immunohistochemical analysis of apoptosis-related factors (Fas, Fas ligand, caspase-3 and single-stranded DNA) in ameloblastomas.

BACKGROUND: To clarify the possible role of apoptotic cell death in oncogenesis and cytodifferentiation of odontogenic epithelium, apoptosis-related factors--Fas, Fas ligand (FasL), caspase-3 and single-stranded DNA (ssDNA)--were analyzed in ameloblastomas as well as in tooth germs. METHODS: Specimens of 5 tooth germs, 29 benign ameloblastomas and 5 malignant ameloblastomas were examined by immunohistochemistry using anti-Fas, FasL, caspase-3 and ssDNA polyclonal antibodies. RESULTS: Immunoreactivity for Fas and FasL was detected in normal and neoplastic odontogenic epithelial cells. Fas expression in ameloblastomas was slightly lower than that in tooth germs, whereas FasL expression was similar in tooth germs and ameloblastomas. Malignant ameloblastomas showed downregulation of Fas expression and upregulation of FasL expression, as compared with benign ameloblastomas, indicating escape from cell death attack by immune cells. Immunoreactivity for caspase-3 was detected chiefly in cells neighboring the basement membrane in tooth germs and ameloblastomas. Expression of caspase-3 and Fas tended to be low in basal cell ameloblastomas and high in desmoplastic ameloblastomas, as compared with other variants of ameloblastomas. Caspase-3 expression was more intense in malignant ameloblastomas than in tooth germs and benign ameloblastomas. Apoptotic bodies reactive with anti-ssDNA antibody were detected in normal and neoplastic odontogenic epithelial cells detached from the basement membrane. Keratinizing cells in acanthomatous ameloblastomas and granular cells in granular cell ameloblastomas showed increased numbers of apoptotic bodies and increased expression of Fas and caspase-3, as compared with other neoplastic cells. Apoptotic reactions in malignant ameloblastomas were less frequent than in benign ameloblastomas, indicating abnormal regulation of cell turnover in odontogenic epithelial cells. CONCLUSION: These apoptosis-related factors were detected in various patterns in normal and neoplastic odontogenic epithelium, suggesting that these factors might be associated with oncogenesis and cytodifferentiation of epithelial odontogenic tumors.