GSTM1 null polymorphisms and oral cancer risk: a meta-analysis.

Many studies have examined the association between the GSTM1 null gene polymorphism and oral cancer risk in various populations, but their results have been inconsistent. To assess this relationship more precisely, a meta-analysis was performed. The PubMed and Embase databases were searched for case-control studies published up to May 2013. Data were extracted and pooled odds ratio (OR) with 95% confidence intervals (CI) were calculated. Ultimately, 39 studies, comprising of 4,704 oral cancer cases and 7,090 controls, were included. Overall, for null versus present, the pooled OR was 1.29 (95% CI = 1.20-1.40), and the heterogeneity was found in all studies. In the stratified analysis by ethnicity, significant risks were found among Asians (OR = 1.39, 95% CI = 1.27-1.53; P = 0.000 for heterogeneity), but not in Caucasians (OR = 0.99, 95% CI = 0.83-1.18; P = 0.677 for heterogeneity). In conclusion, this meta-analysis demonstrates that the GSTM1 null gene polymorphism may be an increased risk of oral cancer in Asians but not in Caucasians.

Prognostic significance of VEGF immunohistochemical expression in oral cancer: a meta-analysis of the literature.

Vascular endothelial growth factor (VEGF) is considered as a prime mediator of angiogenesis and has been implicated in carcinogenesis and metastasis. Various studies examined the relationship between VEGF protein overexpression with the clinical outcome in patients with oral cancer, but yielded conflicting results. Electronic databases updated to March 2013 were searched to find relevant studies. A meta-analysis was conducted with eligible studies which quantitatively evaluated the relationship between VEGF overexpression and survival of patients with oral cancer. Survival data were aggregated and quantitatively analyzed. We performed a meta-analysis of 17 studies (n = 1,207 patients) that evaluated the correlation between VEGF overexpression detected by immunohistochemistry and survival in patients with oral cancer. Combined hazard ratios suggested that VEGF overexpression had an unfavorable impact on overall survival (hazard ratio [HR] = 1.89; 95 % confidence interval [CI], 1.24-2.55) and disease-free survival (HR = 2.08; 95 % CI, 1.14-3.02) in patients with oral cancer: 1.77 (1.09-1.44) in oral squamous cell carcinoma (SCC) patients and 4.28 (1.35-7.21) in adenoid cystic carcinoma (ACC) and mucoepidermoid carcinoma (MEC) of the salivary glands. No significant heterogeneity was observed among all studies. VEGF overexpression indicates a poor prognosis for patients with oral SCC, ACC, and MEC of the salivary glands.

VEGF +936C/T and +460C/T gene polymorphisms and oral cancer risk: a meta-analysis.

Many studies have examined the association between the VEGF +936C/T (rs833061) and +460C/T (rs3025039) gene polymorphisms and oral cancer risk in various populations, but their results have been inconsistent. To assess this relationship more precisely, we performed a meta-analysis. The PubMed, Embase, Web of Science, and China National Knowledge Infrastructure databases were searched for case-control studies that were published up to January 2013. Data were extracted and pooled odds ratios (ORs) with 95 % confidence intervals (CIs) were calculated. Ultimately, six studies were included, comprising 1006 oral cancer cases and 1016 controls. Overall, the pooled OR for VEGF +936 T allele carriers (TC + TT) versus the wild-type homozygotes (CC) was 1.28 (95 % CI 1.04-1.58; P = 0.228 for heterogeneity), the pooled OR for TT versus CC was 1.64 (95 % CI 1.34-1.98; P = 0.315 for heterogeneity), and the pooled OR for the T allele versus the C allele was 1.42 (95 % CI 1.22-1.76; P = 0.286 for heterogeneity). In the stratified analysis by ethnicity, significant risks were found among Caucasians but not Asians. However, there were no associations between VEGF +460C/T and oral cancer risk in only two of the included studies. In conclusion, this meta-analysis demonstrates that the VEGF +936 T allele may be associated with an increased risk of oral cancer, especially among Caucasian populations.

Gene expression of fibrinolytic factors urokinase plasminogen activator and plasminogen activator inhibitor-1 in rabbit temporo-mandibular joint cartilage with disc displacement.

BACKGROUND: The urokinase plasminogen activator system is believed to play an important role in degradation of the extracellular matrix associated with cartilage and bone destruction; however its precise roles in temporomandibular disorders have not yet been clarified. The aims of this study were to investigate the gene expression of fibrinolytic factors urokinase plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) in the articular cartilage of rabbit temporomandibular joint (TMJ) with disc displacement (DD) and to probe the relationship between fibrinolytic activity and cartilage remodeling. METHODS: Disc displacement of right joints was performed in 36 of 78 rabbits under investigation. The animals were sacrificed at 4 days and 1, 2, 4, 8 and 12 weeks after surgery, respectively. The right joints of these animals were harvested and processed for the examination of mRNA expression of uPA and PAI-1 in articular cartilage using in situ hybridization techniques. RESULTS: The expression of uPA and PAI-1 was co-expressed weakly in the chondrocytes from transitive zone to hypertrophic zone and mineralized zone, while no hybridizing signals were shown in proliferative zone and superficial zone in control rabbits. The most striking was the up-regulation of uPA and PAI-1 mRNA in 4-day rabbits postoperatively at the onset of cartilage degeneration. The strongest hybridizing signals for uPA and PAI-1 were seen in 2-week rabbits postoperatively. After 2 weeks, the expression of uPA and PAI-1 began to decrease and reached nearly normal level at 12 weeks. CONCLUSIONS: The expression of the uPA/PAI-1 system coincides with the pathological changes in condylar cartilage after DD. The uPA/PAI-1 system may be one of the essential mediators in articular cartilage remodeling.

[Experimental study of the mechanism of chondroid metaplasia of the bilaminar zone following anterior disc displacement of temporomandibular joint].

PURPOSE: To investigate the source of the metaplasia chondrocytes in the bilaminar zone following anterior disc displacement (ADD) of temporomandibular joint (TMJ). METHODS: 12 Japanese adult rabbits were randomly divided into A and B groups. Each group contained 4 experimental and 2 control rabbits. The disc of the experimental rabbits was induced forward and fixed into the holes made in the zygomatic arch. Group A was stained by HE and examined for the expression of proliferating cell nuclear antigen (PCNA) and fibroblast growth factor receptor 3 (FGFR3) by immunohistochemical methods. Group B was observed under transmission electron microscopy (TEM). RESULTS: Chondrocytes appeared in the bilaminar zone of each experimental rabbit. Both PCNA and FGFR3 were positive in part of them. Under TEM, some cells took on the double characters of chondrocyte and fibroblast and some others appeared the characters of naive cells. CONCLUSIONS: Following ADD of TMJ, some metaplasia chondrocytes might be proliferated and differentiated from mesenchymal stem cells.

[Effect of disc displacement on mRNA expression of urokinase plasminogen activator and its inhibitor-1 in synovial tissues].

OBJECTIVE: To investigate the effect of anterior disc displacement on the expression of urokinase plasminogen activator and its inhibitor-1 (uPA/PAI-1) in synovial tissues. METHODS: Forty Japanese white rabbits were used in this study. The animals were killed at 4 days, 1, 2, 4, 8 and 12 weeks postoperatively, respectively. In situ hybridization technology was applied to detect the expression of uPA/PAI-1 mRNA in synovial membrane. RESULTS: In normal synovial tissues, synovial lining cells and a few fibrosblasts with mild positive staining were occasionally seen. More synovial lining cells and fibrosblasts with moderate postive signals were found 1 week after operation. Since then, the degree of staining for uPA/PAI-1 increased gradually. By the end of 12 weeks postoperatively, strong signals of uPA/PAI-1 mRNA were detected. CONCLUSION: There is a harmonized uPA/PAI-1 system existing in synovial tissues. The high expression of uPA and PAI-1 mRNA in synovial tissues indicates that the uPA/PAI-1 system may play an important role in the process of synovitis resulted from anterior disc displacement.

[The morphology of the cells in the cartilage of rabbit mandibular condyle].

PURPOSE: To study the tissue layers and their function of the cartilage in mandibular condyle in rabbits. METHODS: Six adult Japanese white rabbits were subjected. Their temporomandibular joints were studied by immunohistochemistry for FGFR3 and PCNA, and in situ hybridization for aggrecan and collagen II mRNA expression, as well as ultrastructure. RESULTS: The upper proliferative cells did not express FGFR3, but the lower proliferative cells expressed FGFR3. Only few cells in the upper proliferative layer were PCNA positive, but all cells in the lower proliferative layer were positive for PCNA. No collagen II mRNA expression was found in the upper proliferative cell, but aggrecan and collagen II mRNA coexpressed in the lower proliferative layer. The cells in both layers were different in ultrastructure. CONCLUSION: The cartilage in mandibular condyle should have the 5 following tissue layer: fibrous layer, proliferative layer, transitional layer, cartilaginous layer and calcified cartilaginous layer. The cells in the proliferative layer are undifferentiated and the cells in the differentiated layer are prechondrocytes.

[The relationship between lymphangiogenesis and cervical lymph node micrometastasis in oral squamous cell carcinoma].

OBJECTIVE: To probe the relationship between lymphangiogenesis and cervical lymph node micrometastasis in oral squamous cell carcinoma. METHODS: The microlymphatic vessel density was detected with enzyme histo-chemical method in 47 cases of oral squamous cell carcinoma and 10 cases of normal oral mucosa; 355 lymphnodes were detected with immunohistochemically using monoantibody AE3. RESULTS: The mean MLVD was 14.04 +/- 6.92 in tumor group, or 5.48 +/- 2.62 in normal group. The difference was (P < 0.001). The percentage of tumor with expression CK was 48.9%. The mean MLVD was 16.94 +/- 5.43 in CK positive group, or 11.26 +/- 5.00 in CK negative group, There was difference significant (P < 0.001). CONCLUSIONS: Lymphangiogenesis plays a key role in cervical lymph node micrometastasis of oral squamous cell carcinoma.

[Disc-like changes and type II collagen mRNA expression in the bilaminar zone of rabbit temporomandibular joint following disc displacement].

OBJECTIVE: To study the adaptive alteration in bilaminar zone of rabbits' temporomandibular joint following disc displacement. METHODS: Twenty-six Japanese white rabbits were used in this study. Among these rabbits,6 were used as controls. The right discs of other 20 rabbits were displaced anteriorly by operation. Four of these rabbits were killedatn 1, 2, 4, 6 and 8 weeks respectively after surgery. The TMJS were studied by HE staining, Alcin bluen staining and in situ detection of type II collagen mRNA expression. RESULTS: There appeared cartilage metaplasia after one week following disc displacement. Typical chondrocytes could be found in the bilaminar zone. The new chondrocytes expressed type II collagen. CONCLUSIONS: The bilaminar zone of TMJ will be remodeled following disc displacement and become a disc-like tissue to function as a disc.

[Expression related to vascular endothelial growth factor C and induced nitride oxide synthesizase in lymph node micrometastasis of oral squamous cell carcinoma].

OBJECTIVE: To investigate the relationship of vascular endothelial growth factor C (VEGF-C) and induced nitride oxide synthesizase (iNOS) expression in lymph node micrometastasis of oral squamous cell carcinoma. METHODS: Samples were obtained from 47 cases of oral squamous cell carcinoma and 15 cases with normal oral mucosa, VEGF-C and iNOS mRNA expression were detected by RT-PCR method. Lymph node micrometastasis of 10 normal lymph nodes and 355 lymph nodes from 47 cases of oral squamous cell carcinoma was detected with immunohistochemical reaction in cytokeratin antibody. RESULTS: The percentages in tumors with higher expression were 57.4% for VEGF-C, 68.1% for iNOS (P < 0.05). They were significantly higher than that of normal groups. Significant positive relationship was found between VEGF-C and iNOS (P < 0.01). The positive rate of cytokeratin (CK) was 48.9%. Significant positive relationship was found between VEGF-C and CK, iNOS and CK (P < 0.01). The expression rates of CK in positive group of VEGF-C and iNOS were 63.0%, 65.6% respectively, and were significant higher than negative groups. CONCLUSION: Expression of VEGF-C and iNOS in lymph node micrometastasis of oral squamous cell carcinoma is significant related.