MDM2/p53 co-expression in oral premalignant and malignant lesions: potential prognostic implications.

The expression of MDM2 protein in betel and tobacco related oral malignancies in Indian population, its relationship to clinicopathological parameters and p53 protein expression was investigated. Sixty five oral squamous cell carcinomas (SCCs), 33 premalignant lesions (leukoplakia) and 30 normal oral tissues were assessed by immunohistochemical analysis. MDM2 protein was overexpressed in 51/65 (78%) oral SCCs and 17/33 (52%) premalignant lesions; 11/23 hyperplastic lesions and 6/10 dysplastic lesions. mdm2 gene amplification is an infrequent event in oral tumorigenesis. Elevation in the level of MDM2 protein not only in oral SCCs but also in premalignant lesions suggests that altered MDM2 expression is an early even in the pathogenesis of oral neoplasia. The hallmark of the study was the significant association of MDM2 expression with the p53 protein accumulation in 16/33 (49%) oral premalignant lesions (p = 0.001) and 39/65 (60%) malignant lesions (p = 0.021), suggesting an active role for MDM2 in binding and inactivating p53 in oral tumorigenesis. Further, significant association of MDM2/p53 co-expression was observed with advanced tumour stage (p = 0.0009), as well as lymph node metastasis (p = 0.0325) features associated with aggressive tumour behaviour and poor prognosis. Discordant MDM2+/p53-phenotype was observed in 12/65 (18%) oral SCCs suggesting a p53-independent role for MDM2 in the pathogenesis of a subset of oral carcinomas. In conclusion, alterations in MDM2 and p53 expression are early events likely to be involved in preinvasive stages in oral tumorigenesis and may be indicative of a 'gain of function' phenotype with more aggressive characteristics.     

Stromelysin-3 expression is an early event in human oral tumorigenesis

Stromelysin-3 (ST3/MMP11) is associated with human tumour progression. To determine the clinical significance of ST3 in oral tumorigenesis, its expression was analysed in different stages of tobacco-associated oral cancer. Immunohistochemical analysis of ST3 expression in 79 oral precancerous lesions, 177 SCCs and 35 histologically normal oral tissues was carried out and corroborated by immunoblotting and RT-PCR. ST3/MMP11 protein expression was observed in 45/79 (57%) precancerous lesions [28/48 (58%) with hyperplasia and 17/31 (55%) with dysplasia] and in 123/177 (70%) oral SCCs. In precancerous lesions, ST3 expression was higher compared to normal oral tissues (p = 0.000) and associated with MVD (p = 0.05), a marker for angiogenesis. ST3 was also expressed in cells cultured from precancerous and cancerous lesions that had undergone epithelial-to-mesenchymal transition. In oral cancer patients, ST3 positivity was associated with lymph node involvement (p = 0.025) and increased intratumoral MVD (p = 0.009). Ninety-eight oral SCC patients were followed up for a period of 94 months (median 22.5 months). Kaplan-Meier survival analysis showed that ST3 expression was not a significant prognostic indicator. ST3 expression in oral hyperplastic and dysplastic lesions suggests its association with progression of phenotypic alterations acquired early during the malignant transformation pathway of oral epithelium and implicates it not only in angiogenesis and invasion but also in tumorigenesis. Thus, ST3 may serve as a potential target for developing molecular therapeutics for early intervention in oral tumorigenesis.     

P‐glycoprotein is positively correlated with p53 in human oral pre‐malignant and malignant lesions and is associated with poor prognosis

P‐glycoprotein (Pgp) encoded by the MDR1 gene, a predictor of chemoresistance, may also serve as a prognosticator of clinical outcome in cancer patients. The mutant tumour‐suppressor p53 protein has been shown to activate the MDR1 promoter, whereas the wild‐type p53 represses this activity in cultured cells. We have described the differential expression of Pgp and p53 proteins in betel‐ and tobacco‐related oral tumorigenesis in the Indian population. Herein, Pgp expression was analysed in relation to p53 protein accumulation in pre‐malignant and malignant oral lesions by immuno‐histochemical and flow‐cytometric analyses. The relationship between Pgp and p53 protein accumulation and clinico‐pathological parameters as well as prognosis was determined. Expression of Pgp was observed in 81% of oral squamous cell carcinomas (SCCs) and 71% of pre‐malignant lesions. Sixty‐five of 75 p53‐positive oral SCCs and 21/24 p53‐positive pre‐malignant lesions showed expression of Pgp. Significant correlation between Pgp and p53 expression was found not only in oral SCCs but also in pre‐malignant lesions. Co‐expression of Pgp and p53 proteins was indicative of poor prognosis. Follow‐up studies of 35 patients showed that 7 of 10 oral SCCs with accumulation of Pgp and p53 proteins also exhibited shorter disease‐free survival (recurrence/metastases). Our findings provide clinical evidence for a significant association between Pgp and p53 protein expression in oral tumorigenesis and may account for the aggressive nature of the tumour and poor prognosis. Int. J. Cancer (Pred. Oncol.) 84:80–85, 1999. © 1999 Wiley‐Liss, Inc.     

Prognostic factors in betel and tobacco related oral cancer

Paucity of well-defined prognostic molecular markers severely hampers prediction of the clinical course of squamous cell carcinoma (SCC) of oral cavity. The aim of the study was to evaluate the prognostic significance of impairments in the expression of proteins involved in cell cycle regulation and locoregional spread in oral SCC of habitual betel and tobacco chewers. A prospective study was performed in 105 betel and tobacco consumers with oral SCCs during the period 1988-1999, to evaluate the prognostic relevance of impairments in the expression of proteins involved in cell cycle regulation and locoregional spread. Alterations in the expression of p53, pRb, p16, MDM2, p21, and Ets-1 proteins were determined by immunohistochemical analysis in formalin fixed, paraffin embedded tissue sections from oral SCCs. Analysis of multiple molecular biological factors showed overexpression of p53 in 69/105 (66%) cases, MDM2 in 72/105 (69%) cases, p21 in 57/105 (54%) cases and Ets-1 in 64/105 (61%) cases. Loss of pRb was observed in 58/105 (55%) cases and p16 loss was observed in 72/105 (69%) cases. Interestingly, multivariate analysis revealed loss of pRb as the most significant predictor of advanced tumour stage [P=0.001; Odd's Ratio (OR)=3.5] and overexpression of Ets-1 protein was an independent risk factor for lymph node metastasis (OR: 10.1; P<10(-6)). Multiple logistic regression models showed that pRb loss [Hazard's Ratio (HR): 3.93] and p53 overexpression (HR: 2.97) may serve as adverse prognosticators for disease free survival of the patients. The data demonstrate multiple impairments in p53/MDM2/p21/Ets-1 and p16/pRb pathways in betel and tobacco related oral tumourigenesis.     

Correlation between p53 gene mutations and circulating antibodies in betel- and tobacco-consuming North Indian population

Alterations in p53 tumour suppressor gene and its expression may be implicated in the pathogenesis of betel- and tobacco-related oral cancer. There is wide regional variation in betel- and tobacco-consuming habits in different parts of the Indian subcontinent. The purpose of this study was to determine the correlations between p53 gene mutations, protein accumulation and serum antibodies in oral precancer and cancer. We analysed 30 potentially malignant oral lesions (leukoplakia) and 30 oral squamous cell carcinomas (SCCs) from northern India because the betel quid-consuming habits are different from those prevalent in other regions of India. p53 mutations were analysed by polymerase chain reaction amplification of genomic DNA and direct sequencing, p53 protein accumulation by immunohistochemical analysis and circulating p53 antibodies by ELISA. p53 gene mutations, analysed within exons 5-9, were observed in five out of 30 (17%) potentially malignant oral lesions and seven out of 30 (23%) oral SCCs. All the mutations were base substitution mutations. Three missense and two nonsense mutations were observed in potentially malignant oral lesions, while six missense and one nonsense mutations were identified in oral SCCs. The probable hot spots for the mutations were identified at codons 126, 136 and 174, which have not been observed thus far. A good correlation was observed between p53 missense mutation, p53 antibodies and p53 protein accumulation in matched potentially malignant and malignant oral lesions. All the potentially malignant and cancerous lesions harbouring missense mutations showed accumulation of p53 protein and the majority of these patients showed circulating p53 antibodies suggesting that serological detection of p53 antibodies may serve as a surrogate marker for p53 alterations in oral lesions.     

Expression of RARalpha and RARbeta in human oral potentially malignant and neoplastic lesions

Retinoids reverse potentially malignant lesions and inhibit the development of second primary cancers in patients with head-and-neck cancer. Many of the effects of retinoids result from modulation of gene expression by 2 distinct classes of nuclear receptor, RARs and RXRs; alterations in their expression can lead to tumorigenesis. To determine whether aberrations in expression of the receptors are related to the development of betel- and tobacco-related oral cancer, we used specific monoclonal antibodies against RARalpha and RARbeta to detect expression of these proteins in 30 histopathologically normal tissues, 45 potentially malignant lesions (leukoplakia) with histological evidence of either hyperplasia (31 cases) or dysplasia (14 cases) and 64 oral squamous-cell carcinomas (SCCs) by immunohistochemistry. Of the 30 normal oral tissues analysed, 8 cases showed detectable levels of RARalpha protein, while 10 cases did not show detectable RARbeta immunoreactivity. Immunostaining for RARalpha protein was observed in 12/31 (39%) hyperplastic lesions, 6/14 (43%) dysplastic lesions and 43/64 (67%) oral SCCs. Expression of RARalpha in oral SCC was significantly associated with the histological differentiation status of tumours (p = 0.016). In contrast, lack of detectable immunoreactivity was observed in 19/31 (61%) hyperplastic lesions, 8/14 (57%) dysplastic lesions and 21/64 (33%) oral SCCs. The hallmark of the study was the significant increase in RARalpha immunopositivity in oral SCCs compared to normal tissue (p = 0.0005) and hyperplastic lesions (p = 0.016). One intriguing feature was the significant decrease in RARbeta immunopositivity in hyperplastic lesions compared with normal oral mucosa (p = 0.05) as well as in oral SCCs compared with normal tissues (p = 0.0008).     

Expression of p53R2, newly p53 target in oral normal epithelium,epithelial dysplasia and squamous cell carcinoma

Recently, the p53R2 gene has been isolated and shown to play a crucial role in DNA repair after DNA damage. The p53R2 gene encodes the p53 inducible ribonucleotide reductase small subunit 2 homologue, which is part of the p53 pathway. However, the function of p53R2 in human cancer is still unclear. We investigated p53R2 mRNA expression in human oral normal epithelium, epithelial dysplasias and squamous cell carcinomas (SCCs). Surgical or biopsy-proven specimens of 10 normal epithelium, 48 epithelial dysplasias and 63 SCCs were collected in our department. Then, p53R2 was identified by in situ hybridization to visualize and localize the expression of specific mRNAs. The authors examined the p53 gene mutation by polymerase chain reaction-single strand conformation polymorphism analysis. p53, mdm2, p21^WAF1/CIP1 and Ki-67 expression was detected by immunohistochemistry. p53R2 expression was detected in none of ten normal epithelium (0%), ten of 48 dysplasias (20.8%) and 33 of 63 SCCs (52.4%). In oral SCC, the expression of p53R2 was significantly associated with tumor size, lymph node metastasis and histological differentiation (P=0.014, 0.046 and 0.022, respectively). p53R2 expression was significantly associated with p53 abnormality in epithelial dysplasia and SCC (P=0.034 and 0.009, respectively). Of 63 patients, 37 received preoperative radiochemotherapy. p53R2 mRNA expression was significantly associated with the pathologic response to radiochemotherapy (P=0.031). This study suggested that p53R2 expression could be associated with oral carcinogenesis. The presence of p53R2 mRNA expression would be a predictive factor for tumor development, tumor cell differentiation and the sensitivity to radiochemotherapy in oral SCC.     

Thrombospondin-1 expression in oral squamous cell carcinomas: correlations with tumor vascularity, clinicopathological features and survival

Thrombospondin-1 (TSP-1) is a 450 kd glycoprotein synthesized and incorporated into the extracellular matrix by numerous cell types and reported to suppress tumor growth and progression by its inhibition of angiogenesis. In order to clarify the biological role of TSP-1 and determine its clinicopathological significance in oral squamous cell carcinomas (SCCs), we identified TSP-1 protein expression in 54 oral SCCs by immunohistochemistry and correlated it with microvessel density (MVD), clinicopathological features and patient's survival. Thirty-two out of 54 carcinomas (59%) were identified as having a low level of TSP-1 expression (TSP-1-L), and 22/54 (41%) carcinomas identified as having a high level of TSP-1 expression (TSP-1-H). The MVD counts (mean±S.D.=9.0±4.9) in TSP-1-H tumors was significantly lower than that (mean±S.D.=12.7±4.4) in TSP-1-H tumors (P=0.0065). The level of TSP-1 expression was not correlated with T category and histologic grade, but inversely correlated with the pattern of tumor invasion (P=0.0136) and with lymph nodal status (P=0.0119). Furthermore, Kaplan–Meier analysis showed that the 5-year survival rate of TSP-1-H group was significantly higher than that of TSP-l-L group. Our results suggested that TSP-1 expression exerts an inhibitory effect on tumor vascularity, and that it has value in assessment of aggressiveness and prognosis of oral SCCs.     

Induction of apoptosis by abrogation of HSP70 expression in human oral cancer cells

We have reported differential expression of 70-kDa heat shock protein (HSP70) in human oral tumorigenesis. The functional significance of elevated levels of HSP70 protein in oral squamous cell carcinomas (SCC) remains to be elucidated. The present study was designed to investigate the role of HSP70 protein in the proliferation and survival of oral tumour cells. Abrogation of HSP70 expression by antisense HSP70 oligonucleotides treatment of human oral carcinoma cells isolated from primary tumours or HSC-2 cells triggered cell death with several characteristic features, including DNA laddering, chromatin condensation and fragmentation. Flow-cytometric analysis showed a hypodiploid DNA peak of propidium iodide-stained nuclei in the antisense oligomer-treated cells. This response was accompanied by a decrease in the percentage of cells in the S phase of the cell cycle, suggesting inhibition of cell proliferation. Treatment of oral cancer cells with HSP70 antisense oligomers resulted in decreased expression of anti-apoptotic signal protein bcl-2. Our results suggest that HSP70 antisense oligomer treatment abrogates the expression of HSP70 protein that may disrupt HSP70-bcl-2 interactions, in turn inhibiting cell proliferation and inducing apoptosis. Conversely, the data suggest that HSP70 is required for proliferation and survival of oral tumour cells.     

Allelic loss on chromosomes 2q, 3p and 21q: possibly a poor prognostic factor in oral squamous cell carcinoma

Loss of heterozygosity (LOH) correlates with inactivate tumor suppressor gene. The aim of this study was to see if LOH on chromosomes 2q, 3p and 21q correlated with a poor prognostic factor in oral squamous cell carcinoma (SCC). We analyzed chromosomes 2q, 3p and 21q for LOH in 40 primary oral SCCs using 30 markers and constructed a deletion map for these chromosome arms. Significant LOH (>20%) occurred at alleles in chromosome bands 2q14–21 (21.7%), 2q32–35 (31.6%), 2q35 (21.1%), 2q36 (36.7%), 3p25 (32.4%), 3p21.3 (23.8%), 21q11.1 (52.4%), 21q21 (21.6%) and 21q22.1 (22.2%). A significant correlation was observed between the number of regions showing LOH at 2q and TNM clinical stage (P=0.0063), consistent with the progressive accumulation of genetic errors during the development oral SCC. The number at more than two LOH loci was significant with a poor prognosis at 2q (P=0.0208). These findings demonstrate that oral SCC exhibits genetic alterations at multiple loci and that allelic loss at more than two locations is indicative of a poor prognosis. This is the first study to demonstrate the prognostic significance of LOH at 2q, 3p and 21q for oral cancer and may help to identify patient who should receive more aggressive treatment.     

Differential expression of 70–kDa heat shock-protein in human oral tumorigenesis

To understand the biological events underlying the multistep process of oral tumorigenesis we have studied the expression of 70–kDa heat-shock protein, HSP70, in human normal, pre-malignant and malignant oral tissues. Expression of HSP70 was assessed in oral-tissue specimens using a mouse monoclonal antibody against HSP70 by immunostaining and immunoblot-ting analysis. Strong nuclear and cytoplasmic HSP70 immunostaining was observed in oral squamous-cell carcinomas (30/ 38). Mild to moderate HSP70 expression was observed in oral dysplastic lesions (19/30) and basal low level of HSP70 was observed in normal oral tissues. The results were corroborated by immunoblotting analysis. The wide variation in HSP70 expression in normal, pre-malignant and malignant oral lesions suggests that it is differentially expressed during oral carcinogen-esis and may be implicated in tumor development. © 1995 Wiley-Liss, Inc.     

Prognostic significance of EGFR and Her-2 in oral cavity cancer in betel quid prevalent area cancer prognosis

Although several studies have found overexpression of epidermal growth factor receptor (EGFR) proteins EGFR and Her-2 in head and neck cancers, the clinical relevance of the finding varies. We examined the expression and clinical association of these molecules with oral squamous cell carcinoma in an area where betel chewing is prevalent. EGFR and Her-2 proteins were measured in 59 paired (grossly normal and cancer) tissues by an enzyme immunoassy method. The cutoff value for gene overexpression was defined as the level of mean expression in normal tissue plus two s.d. A total of 59% of the patients consumed alcohol, 90% smoked tobacco, and 90% chewed betel quid. Of the patients assayed, 34 (58%) and 24 (41%) had EGFR and Her-2 overexpression, with average 3.5- and 1.5-fold elevations. EGFR overexpression has been shown to be statistically associated with T stage, N stage, overall TMN stage, primary tumour depth, lymph node extra-capsular spread, and poor survival. Her-2 overexpression, however, did not demonstrate a similar association with clinicopathological parameters or therapeutic outcome. On multivariant analysis, EGFR overexpression (P=0.041) and N stage (P=0.024) were the only independent factors for overall survival. These results indicate that the molecular targeting therapy to EGFR may be a treatment for oral cavity cancer in the betel quid-chewing prevalent area.     

p53对绝经后HR阳性、HER-2阳性术后乳腺癌患者内分泌药物疗效的预测价值

目的 探讨p53蛋白表达对绝经后激素受体(HR)阳性、HER-2阳性术后乳腺癌患者辅助内分泌药物疗效的预测价值。方法 筛选符合条件的乳腺癌病例172例,经免疫组织化学SP法检测癌组织中ER、PR、HER-2、p53蛋白的表达情况,分析p53蛋白表达与不同临床病理特征之间的关系及其对患者预后的影响。结果 p53蛋白表达与肿瘤大小、淋巴结状态、组织学分级、ER及PR表达均无关。中位随访68个月(4~131个月),Log-rank单因素分析显示,淋巴结状态(χ²=46.602;P＜0.001)、是否放射治疗(χ²=9.617;P=0.002)与乳腺癌患者的无病生存期(DFS)有关,但p53表达与乳腺癌患者DFS无关(χ²=0.002,P=0.968)。Cox多因素分析显示,乳腺癌患者DFS仅与淋巴结转移数目有关(HR=2.121,95%CI:1.630~2.760,P＜0.001)。亚组分析显示,口服他莫昔芬(TAM)组患者中,p53阳性者DFS优于p53阴性者(χ²=4.695,P=0.030);而口服其芳香化酶抑制剂(AI)组患者中,p53阴性者DFS优于p53阳性者(χ²=5.995,P=0.014)。结论 p53蛋白阳性表达是TAM有效治疗的预测因子,而p53蛋白阴性表达是AI有效治疗的预测因子。     

Co-expression of colligin and collagen in oral submucous fibrosis: plausible role in pathogenesis

The high incidence of oral submucous fibrosis (OSF), a potentially malignant condition of the oral cavity, in the Indian subcontinent is causally associated with commonly prevailing habit of chewing areca nut and tobacco. Knowledge of molecular alterations in OSF is meagre. OSF is characterised by progressive accumulation of collagen fibres in lamina propria and oral submucosa. Colligin/HSP47 is a 47KDa stress protein which acts as a chaperone for collagen. We hypothesized that since colligin plays a vital role in folding and assembling collagen it may be involved in the pathogenesis of OSF. The present study was undertaken in tobacco and areca nut chewing Indian OSF patients to investigate the correlation, if any, between the expression of colligin and collagen type I proteins in OSF lesions. Immunohistochemical analysis showed overexpression of colligin and collagen type I proteins in 16/23 (70%) and 15/23 (65%) of OSF cases, respectively. The hallmark of the study was the significant association between the increased expression of type I collagen and its chaperone, colligin, in OSF lesions (P=0.0494). The data suggest that the increased levels of colligin in OSF may contribute to the deposition of collagen and consequent increased fibrosis in the oral submucosa in OSF lesions.     

Overexpression of p53 protein in betel- and tobacco-related human oral dysplasia and squamous-cell carcinoma in India

The aetiological factors for oral cancer are not the same in India and in Western countries. Epidemiological studies have shown a correlation between high incidence of oral cancer and heavy consumption of betel and/or tobacco in the Indian population, while this stud/ indicates an association with a genetic change. The p53 tumour-suppressor gene is the most commonly identified mutated gene in human malignancies. Expression of p53 protein was examined in premalignant and malignant oral lesions from Indian patients who were consumers of betel, areca nut and/or tobacco, using anti-p53 monoclonal antibodies PAb 1801 and PAb 421. Cryosections from normal, premalignant or malignant oral mucosa were used for immunostaining and the observations were confirmed by immunoprecipitation. P53 protein was detected in 55% (15/27) premalignant oral lesions (leukoplakia). Strong p53-positive staining was detected in 75% (24/32) of oral squamous-cell carcinomas. Normal oral mucosa did not show positive p53 staining (0/24). The detection of p53 protein in premalignant oral lesions suggests that p53 aberrations are an early event in the development of oral cancer in India. The high incidence of p53 positivity in leukoplakia may be due to differences in aetiological factors. p53 overexpression in premalignant oral lesions is important in view of the significantly earlier onset of leukoplakia in the Indian population compared to the development of oral malignancy, and may be helpful in identifying lesions that are more likely to progress to malignancy. The frequency of p53 protein overexpression was high in premalignant and malignant oral lesions of patients who were heavy consumers of betel, areca nut and tobacco.     

胃癌组织中miR-320a和CYLD的表达及与临床病理特征及预后的关系

目的 研究miR-320a和头帕肿瘤综合征蛋白(CYLD)在胃癌患者中的表达及其与临床病理特征及预后的关系。方法 选取2013年3月—2014年11月在我院行肿瘤切除术的460例胃癌患者作为研究对象, 分别收集患者肿瘤组织及癌旁非肿瘤胃粘膜组织, 采用荧光定量PCR检测miR-320a和CYLD mRNA表达水平, 采用免疫组织化学染色法检测CYLD蛋白表达, 分析miR-320a和CYLD表达水平及其与临床病理特征及预后的关系。结果 miR-320a和CYLD mRNA在肿瘤组织中的相对表达量为(0.37±0.09)、(0.91±0.23), 在癌旁非肿瘤组织中的相对表达量为(0.86±0.15), (1.56±0.42), miR-320a和CYLD mRNA在肿瘤组织中的相对表达量与非肿瘤组织比较, 差异具有统计学意义(t=60.078, 29.113, P＜0.001);CYLD蛋白在肿瘤组织中的阳性表达率43.48%与癌旁非肿瘤组织73.91%比较, 差异具有统计学意义(χ²=86.624, P=0.003);miR-320a表达水平与患者肿瘤直径和淋巴结转移有关(χ²=25.859, 13.742, P＜0.05);YLD表达水平与患者TNM分期和肿瘤分化程度有关(χ²=37.725, 59.323, P＜0.05)。miR-320a低表达患者中位生存期(20.36±0.56)(95% CI:19.252~21.462)与miR-320a高表达患者中位生存期(28.29个月95% CI:27.158~29.412个月)比较, 差异具有统计学意义(χ²=87.967, P＜0.001);CYLD阴性表达患者中位生存期(17.70个月95% CI:16.599~18.796个月)与CYLD阳性表达患者中位生存期(26.74个月95% CI:25.474~27.997个月)比较, 差异具有统计学意义(χ²=109.887, P＜0.001);miR-320a和CYLD共表达患者中位生存期(29.01个月95% CI:26.831~28.946个月)与非共表达患者中位生存期(17.13个月95% CI:17.214~19.568个月)比较, 差异具有统计学意义(χ²=117.680, P＜0.001)。肿瘤组织miR-320a与CYLD mRNA表达水平呈正相关(r=0.607, P＜0.001);miR-320a低表达、CYLD阴性表达、TNM分期、淋巴结转移及肿瘤分化程度是影响胃癌患者预后的独立危险因素(HR=1.939、2.180、1.561、1.719、1.608, 95% CI:1.141~3.295, 1.252~3.796, 1.014~2.403, 1.115~2.650, 1.097~2.357, P＜0.05)。结论 miR-320a和CYLD在胃癌患者肿瘤组织中表达量明显降低, 与疾病发生发展及不良预后有关, 是潜在的胃癌诊断及治疗新靶点。     

Betel quid and oral cancer: prospects for prevention.

Betel-quid chewing is an ancient and socially accepted practice. The introduction of tobacco reinforced this practice, and now almost all habitual chewers of betel quids include tobacco. It is well established that chewing of betel quid with tobacco causes oral cancer and is largely responsible for the high incidence of oral cancer in several South Asian countries. The feasibility of primary prevention of oral cancer was studied in a population-based prospective intervention study. A cohort of 12,212 betel-quid chewers and smokers was exposed to a programme of health education for stopping chewing and smoking and subjected to annual examinations for detection of oral precancerous lesions. Evaluations after one, five and eight years showed that primary prevention of oral cancer is feasible and practicable. Early detection of oral cancer is an important control measure. In a secondary prevention study, 53 basic health workers were trained in the detection and referral of lesions suspected of being oral cancer. Over one year, they examined more than 39,000 high-risk individuals, resulting in the detection of 20 cases of oral cancer. The sensitivity and specificity of their diagnoses was assessed through a re-examination of a 5% sample: we concluded that it was possible to incorporate a secondary prevention programme into the existing health care system.     

Retinoic acid receptor-alpha as a prognostic indicator in oral squamous cell carcinoma

Retinoids reverse potentially malignant lesions and inhibit the development of second primary tumors in oral cancer patients by binding to nuclear retinoid receptors. Alterations in the expression of retinoid receptor-alpha are implicated in tumor progression. Herein, we hypothesized that increased expression of RARalpha protein in oral squamous cell carcinoma (SCC) is associated with a poor clinical outcome and thus may serve as a prognostic factor. Retrospective immunohistochemical analysis of RARalpha protein expression was carried out in paraffin-embedded tissue sections from 115 patients with completely resected oral SCCs for whom clinical follow-up data were available. Increased expression of RARalpha protein was observed in 67/115 (58%) oral SCCs (weakly positive in 38 patients and strongly positive in 29 patients). Kaplan-Meier analysis showed that patients with RARalpha positivity had significantly shorter disease-free survival time (median time 40 months vs. 86 months, p = 0.0229). Furthermore, disease-free survival time of the 29 patients with strongly positive RARalpha was significantly worse than for the 86 patients with weak or undetectable levels of RARalpha (p = 0.0328). Strong RARalpha expression in oral SCCs was associated with a significantly worse disease-free survival, suggesting that RARalpha may serve as a prognostic indicator of poor clinical outcome. Further studies are warranted to determine its utility in identifying the subset of patients who would benefit from use of retinoids as adjuvant in chemotherapy or chemopreventive approaches.     

Low incidence of p53 mutations in betel quid and tobacco chewing-associated oral squamous carcinoma from India

Mutations of the p53 tumor suppressor gene have been found to be the single most frequent event in human cancers. In India and other southeast Asian countries tobacco chewing with betel quid was attributed to be the major factor in oral carcinogenesis. We have analyzed 72 untreated primary oral squamous cell carcinomas (SCCs) for mutations in the tumor suppressor gene p53 exons 4-9 by PCR-SSCP and DNA sequencing. Sequencing analysis revealed 16 missense mutations, one silent mutation in codon 307 and four A to G substitution polymorphism in codon 213. The incidence of p53 mutation was 21% (15 of 72) excluding the polymorphism and the silent mutation. Eight mutations were clustered in codons 266-282 of exon 8. Of the total mutation events 37.5% were G to A transitions and 31.3% were G to T transversions. These results indicate the possible involvement of tobacco derived nitrosamines and their adducts in the genesis of oral cancer among Indians.     

Promoting activity of betel quid ingredients and their inhibition by retinol

Ingredients of betel quids, which have been linked to the high incidence of precancerous oral lesions and oral cancers, were examined for their promoting activity. Aqueous extracts were tested using the bovine papillomavirus (BPV) DNA transformation assay, which consists of cultured C3H/10T1/2 cells transfected with the plasmid pdPBV-1 as targets, and the frequency of transformed foci as endpoints. Areca nut extracts enhanced the formation of BPV DNA-induced transformed foci approximately tenfold. No promoting activity was detected in two samples of chewing tobacco examined. The addition of retinol to the areca nut extract inhibited its tumour promoting effect in a dose-dependent manner, completely abolishing the promoting activity at a dose of 10(-6) M. The experimental results are compared with epidemiological data on oral cancer incidences among chewers of different areca nut/tobacco mixtures and with the chemopreventive effect of vitamin A administered to betel quid chewers.