Regional difference in intratumoral lymphangiogenesis of oral squamous cell carcinomas evaluated by immunohistochemistry using D2-40 and podoplanin antibody: an analysis in comparison with angiogenesis

BACKGROUND: Whether tumor cells induce lymphangiogenesis intratumorally or permeate pre-existing lymphatic vessels in the peritumoral area still remains unclear. In this study, we investigated in detail the intratumoral lymphangiogenesis of oral squamous cell carcinomas (SCC) in comparison with tumor angiogenesis. METHODS: Immunohistochemistry with D2-40, podoplanin antibody, and CD34 antibody were used to evaluate the lymphatic vessel density (LVD) and blood microvessel density (MVD). Vascular endothelial growth factor (VEGF) and VEGF-C expressions of oral SCC were also assessed by immunohistochemistry. RESULTS: LVD significantly increased in the superficial area of tumor tissue compared with normal mucosa, whereas it decreased in the deep area of intratumoral tissue near the invasion front, in sharp contrast to MVD, which significantly increased throughout tumor tissue. Consistent with the decreased intratumoral LVD and increased intratumoral MVD, VEGF-C expression of tumor cells was down-regulated in the deep area of tumor tissue, while VEGF expression of tumor cells was up-regulated throughout the tumor tissue. CONCLUSIONS: Lymphangiogenesis in oral SCC varies depending on the region within the tumor tissue. It is not induced in the genuine tumor stroma near the invasion front, probably due to the down-regulation of VEGF-C expression of tumor cells, which is different from VEGF-mediated induction of intratumoral angiogenesis.     

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.     

p53 gene status and expression of p53, MDM2, and p14ARF proteins in ameloblastomas

BACKGROUND: To clarify the roles of the p53-MDM2-p14(ARF) cell cycle regulation system in oncogenesis and cytodifferentiation of odontogenic tumors, p53 gene status and expression of p53, MDM2, and p14(ARF) proteins was analyzed in ameloblastomas as well as tooth germs. METHODS: Paraffin sections of 16 tooth germs and 46 benign and 5 malignant ameloblastomas were examined immunohistochemically for the expression of p53, MDM2, and p14(ARF) proteins. Frozen tissue samples of 10 benign ameloblastomas and 1 malignant (metastasizing) ameloblastoma were analyzed by direct DNA sequencing to detect p53 gene alteration. RESULTS: Immunohistochemical reactivity for p53 was detected in 2 of 13 tooth germs, 13 of 29 ameloblastomas, and 5 of 5 malignant ameloblastomas, and the expression ratio of p53 in tooth germs was significantly lower than those in benign and malignant ameloblastomas. Direct DNA sequencing showed no alteration of p53 gene exons 5-8 in any sample of 10 benign ameloblastomas and 1 metastasizing ameloblastoma. Expression of MDM2 and p14(ARF) was detected in all samples of normal and neoplastic odontogenic epithelium, and the expression ratios in tooth germs tended to be lower than those in benign and malignant ameloblastomas. In ameloblastomas, expression of p53, MDM2, and p14(ARF) was significantly higher in plexiform cases than in follicular cases. Markedly decreased reactivity for p53, MDM2, and p14(ARF) was detected in keratinizing and granular cells in ameloblastoma subtypes. Basal cell ameloblastoma showed slightly higher reactivity for p53, MDM2, and p14(ARF) as compared with other subtypes. CONCLUSION: Elevated expression of p53, MDM2, and p14(ARF) in benign and malignant ameloblastomas suggests that alteration of the p53-MDM2-p14(ARF) cascade is involved in oncogenesis and/of malignant transformation of odontogenic epithelium. p53 gene status implied that p53 mutation might play a minor role in neoplastic changes of odontogenic epithelium. Immunoreactivity for p53, MDM2, and p14(ARF) in ameloblastoma variants suggests that these factors might be associated with tissue structuring and cytodifferentiation of ameloblastomas.     

口腔鳞癌中COX-2的表达与淋巴管生成的关系

目的:检测口腔鳞癌中环氧合酶-2(COX-2)和微淋巴管密度(MLVD)的表达,探讨COX-2与口腔鳞癌淋巴管生成的关系及临床意义.方法:应用免疫组织化学染色(S-P法)检测40例口腔鳞癌组织、14例正常口腔黏膜组织中COX-2的表达情况.应用免疫双重组织化学染色检测肿瘤中的MLVD.结果:COX-2 在口腔鳞癌中的阳性表达率为70.0 %,明显高于对照组(P ＜ 0.01).COX-2的表达与口腔鳞癌颈淋巴结转移、TNM分期相关(P ＜0.05).COX-2表达阳性组的MLVD值为23.3±1.9,显著高于阴性组的MLVD值16.9±2.2( t ＝ 9.295,P ＜ 0.01).结论:COX-2在口腔鳞癌组织中表达明显上调,并与淋巴管生成、颈淋巴结转移及TNM分期等临床病理生物学行为有关,COX-2可能在口腔鳞癌的生长及转移中起重要作用.     

Mutational analysis of Wnt signaling molecules in ameloblastoma with aberrant nuclear expression of β‐catenin

Background: To clarify the genetic background of ameloblastoma, expression of β‐catenin, and mutational status of genes involved in Wnt signaling pathway were investigated. Methods: We analyzed β‐catenin and cyclin D1 in 18 cases of ameloblastoma by immunohistochemical staining, and searched for mutations in CTNNB1 (gene for β‐catenin), APC, AXIN1, and AXIN2 by polymerase chain reaction (PCR) and direct sequencing method. Result: We detected membranous and occasionally cytoplasmic expression of β‐catenin in 16 of 18 cases (89%), and nuclear expression of β‐catenin principally in the peripheral columnar cells in 11 of 18 cases (61%). In nine of the 18 cases (50%), we detected the expression of cyclin D1 principally in the peripheral columnar cells. However, there was no correlation between nuclear expressions of β‐catenin and cyclin D1. No missense mutations were found in CTNNB1, APC, AXIN1, and AXIN2 in all cases except for silent mutation and already‐known single nucleotide polymorphism. Conclusion: Mutations in CTNNB1, APC, AXIN1, and AXIN2 are not implicated in nuclear accumulation of β‐catenin, and that the expression of cyclin D1 is accelerated independently of β‐catenin in ameloblastomas. Other Wnt signaling members or alternative pathways involved in the degradation of β‐catenin should be subject of further investigation.     

Immunohistochemical expression of DNA methyltransferases 1, 3a and 3b in oral leukoplakias and squamous cell carcinomas

Over-expression of DNA methyltransferases DNMT1, DNMT3a and DNMT3b has been reported in various cancers and precancerous lesions.

Objective

To investigate DNMT1, DNMT3a and DNMT3b enzymes in oral squamous cell carcinoma (SCC) and leukoplakia, and their relationship with histopathologic/clinical parameters.

Study design

Immunohistochemistry was carried out to evaluate the three DNMTs in 60 samples of oral SCC and 37 samples of oral leukoplakia.

Results

DNMT3a immunoreactivity in the three groups of oral SCC (39.8%) was significantly higher than in control (22.6%) (ANOVA, Student–Newman–Keuls test, P < 0.05), but not when compared to oral leukoplakia groups (28.2%). For DNMT1 and DNMT3b, there were no statistically significant differences between oral SCC groups (65% and 74.7%), oral leukoplakia groups (68.3% and 70.9%) and control (65.4% and 76.5%). There was a significantly higher mean percentage of DNMT1 immunoreactivity in non-smokers (ANOVA, P = 0.048), and a higher DNMT3a immunoreactivity in alcohol users (ANOVA, P = 0.01).

Conclusions

Higher DNMT3a immunopositivity may be associated with oral SCC and alcohol use, whilst lower levels of DNMT1 may be related with smoking habit. However, there was a significantly higher mean percentage of DNMT1 immunoreactivity in non-smokers (ANOVA, P = 0.048), and a higher DNMT3a immunoreactivity in alcohol users (ANOVA, P = 0.010).     

口腔鳞状细胞癌中血管内皮生长因子-C的表达及其与血管、淋巴管生成、淋巴结转移的关系

目的探讨血管内皮生长因子-C（VEGF-C）在口腔鳞状细胞癌（OSCC）组织中的表达情况及其与血管、淋巴管生成、淋巴结转移之间的关系。方法调查拥有完整临床病理资料的67例口腔鳞癌患者的手术切除标本,采用SP免疫组化技术检测VEGF-C的表达情况并分析其与微血管密度（MVD）、淋巴管密度（LVD）及其他临床病理指标的关系。结果晚期病例、淋巴结转移阳性病例的VEGF-C表达明显升高（P值分别为0.015和<0.001）,而VEGF-C表达与患者性别、肿瘤部位、肿瘤分化程度无关（P>0.05）。VEGF-C高表达组的LVD明显高于VEGF-C低表达组（P=0.001）,但两组间MVD无统计学差异（P=0.125）。此外,淋巴结转移阳性组的LVD明显高于淋巴结转移阴性组（P=0.026）。结论VEGF-C可能主要通过参与诱导口腔鳞癌淋巴管生成促进淋巴结转移。