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1.  Oesophageal squamous cell carcinoma in high-risk Chinese populations: Possible role for vascular epithelial growth factor A 
Mechanisms involved in wound healing play some role in carcinogenesis in multiple organs, likely by creating a chronic inflammatory milieu. This study sought to assess the role of genetic markers in selected inflammation-related genes involved in wound healing (interleukin (IL)-1a, IL-1b, IL-1 Receptor type I (IL-1Ra), IL-1 Receptor type II (IL-1Rb), tumour necrosis factor (TNF)-α, tumour necrosis factor receptor superfamily member (TNFRSF)1A, nuclear factor kappa beta (NF-kB)1, NF-kB2, inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, hypoxia induced factor (HIF)-1α, vascular endothelial growth factor (VEGF)A and P-53) in risk to oesophageal squamous cell carcinoma (OSCC).
We genotyped 125 tag single nucleotide polymorphism (SNP)s in 410 cases and 377 age and sex matched disease-free individuals from Nutritional Intervention Trial (NIT) cohort, and 546 cases and 556 controls individually matched for age, sex and neighbourhood from Shanxi case–control study, both conducted in high-risk areas of north-central China (1985–2007). Cox proportional-hazard models and conditional logistic regression models were used for SNPs analyses for NIT and Shanxi, respectively. Fisher's inverse test statistics were used to obtain gene-level significance.
Multiple SNPs were significantly associated with OSCC in both studies, however, none retained their significance after a conservative Bonferroni adjustment. Empiric p-values for tag SNPs in VEGFA in NIT were highly concentrated in the lower tail of the distribution, suggesting this gene may be influencing risk. Permutation tests confirmed the significance of this pattern. At the gene level, VEGFA yielded an empiric significance (P = 0.027) in NIT. We also observed some evidence for interaction between environmental factors and some VEGFA tag SNPs.
Our finding adds further evidence for a potential role for markers in the VEGFA gene in the development and progression of early precancerous lesions of oesophagus.
PMCID: PMC4363989  PMID: 25172294
Oesophageal squamous; cell carcinoma; Inflammation; Wound-healing; Genetic marker; Genetics; Inflammation-related events; Vascular endothelial growth factor A; VEGFA
2.  The Aetiological Role of Human Papillomavirus in Oesophageal Squamous Cell Carcinoma: A Meta-Analysis 
PLoS ONE  2013;8(7):e69238.
The aetiological role of human papillomavirus (HPV) in oesophageal squamous cell carcinoma (OSCC) has been widely researched for more than three decades, with conflicting findings. In the absence of a large, adequately powered single case-control study, a meta-analysis of all available case-control studies is the most rigorous way of identifying any potential association between HPV and OSCC. We present the first global meta-analysis of case-control studies investigating the role of HPV in OSCC.
Case-control studies investigating OSCC tissue for presence of HPV DNA were identified. 21 case-control studies analyzing a total of 1223 cases and 1415 controls, met our inclusion criteria. HPV detection rates were tabulated for each study and all studies were assessed for quality. The random effects method was used to pool the odds ratios (OR).
From all OSCC specimens included in this meta-analysis, 35% (426/1223) were positive for HPV DNA. The pooled OR for an HPV-OSCC association was 3.04 (95% CI 2.20 to 4.20). Meta-regression analysis did not find a significant association between OR and any of the quality domains. Influence analysis was non-significant for the effect of individual studies on the pooled estimate. Studies conducted in countries with low to medium OSCC incidence showed a stronger relationship (OR 4.65, 95% CI 2.47 to 8.76) than regions of high OSCC incidence (OR 2.65, 95% CI 1.80 to 3.91).
Uncertainty around the aetiological role of HPV in OSCC is due largely to the small number and scale of appropriately designed studies. Our meta-analysis of these studies suggests that HPV increases the risk of OSCC three-fold. This study provides the strongest evidence to date of an HPV-OSCC association. The importance of these findings is that prophylactic vaccination could be of public health benefit in prevention of OSCC in countries with high OSCC incidence.
PMCID: PMC3722293  PMID: 23894436
3.  Prevalence of human papillomavirus among oesophageal squamous cell carcinoma cases: systematic review and meta-analysis 
British Journal of Cancer  2014;110(9):2369-2377.
Oncogenic human papillomavirus (HPV) has been hypothesised as a risk factor for oesophageal squamous cell carcinoma (OSCC), but aetiological research has been limited by the varying methodology used for establishing HPV prevalence. The aims of this systematic review and meta-analysis were to estimate the prevalence of HPV DNA detected in OSCC tumours and the influence of study characteristics.
Study-level estimates of overall and type-specific HPV prevalence were meta-analysed to obtain random-effects summary estimates.
This analysis included 124 studies with a total of 13 832 OSCC cases. The average HPV prevalence (95% confidence interval) among OSCC cases was 0.277 (0.234, 0.320) by polymerase chain reaction; 0.243 (0.159, 0.326) by in situ hybridisation; 0.304 (0.185, 0.423) by immunohistochemistry; 0.322 (0.154, 0.490) by L1 serology; and 0.176 (0.061, 0.292) by Southern/slot/dot blot. The highest HPV prevalence was found in Africa and Asia, notably among Chinese studies from provinces with high OSCC incidence rates.
Future research should focus on quantifying HPV in OSCC cases using strict quality control measures, as well as determining the association between HPV and OSCC incidence by conducting large, population-based case–control studies. Such studies will provide a richer understanding of the role of HPV in OSCC aetiology.
PMCID: PMC4007246  PMID: 24619077
oesophageal squamous cell carcinoma; human papillomavirus; meta-analysis
4.  Evidence for the aetiology of human papillomavirus in oesophageal squamous cell carcinoma in the Chinese population: a meta-analysis 
BMJ Open  2013;3(11):e003604.
We aimed to conduct a meta-analysis of human papillomavirus (HPV) as a risk factor for oesophageal squamous cell carcinoma (OSCC) in China, using all eligible studies published in the English and Chinese language literature.
The random effect model was used to analyse the pooled OR. The I2 and Q tests were included in the subgroup analyses.
Literature searches of databases including MEDLINE, PUBMED, EMBASE and Chinese National Knowledge Infrastructure (CNKI) and other available resources were performed to retrieve studies investigating OSCC tissue from Chinese participants for the presence of HPV DNA.
Primary outcome measure
A collective analysis of OSCC cases and control specimens was carried out from 15 case–control studies (6 in the English language and 9 in the Chinese language) for HPV prevalence.
Of a total of 1177 OSCC and 1648 oesophageal control samples, 55% (642/1177) of cancer specimens and 27% (445/1648) of control samples were positive for HPV DNA. A positive strong association between HPV DNA and OSCC was observed among the included studies, with a pooled OR of 3.69 (95% CI 2.74 to 4.96). Heterogeneity and publication bias were not observed in the analysis. Subgroup analyses of the included studies also supported the measure of association of causal links between HPV and OSCC.
This meta-analysis provides the strongest evidence until now of an association between HPV and OSCC in the Chinese population. China has a high burden of OSCC, making this an important research finding. A strength and new contribution of this study is combining data from the English and Chinese language literature to analyse all studies conducted in China. These findings may inform the population level use of prophylactic HPV vaccination to reduce the burden of OSCC in China.
PMCID: PMC3831092  PMID: 24240141
5.  Gastric atrophy and oesophageal squamous cell carcinoma: possible interaction with dental health and oral hygiene habit 
British Journal of Cancer  2012;107(5):888-894.
Gastric fundal atrophy has been hypothesised to increase the risk of oesophageal squamous cell carcinoma (OSCC), but studies have shown inconsistent results.
We measured serum pepsinogen I (PGI) and pepsinogen II (PGII) among 293 incident cases and 524 matched neighbourhood controls in a high-risk area of Northern Iran. Conditional logistic regression model was used to estimate odds ratios (ORs) and their 95% confidence intervals (CIs).
After controlling for age, sex, residence area and other potential confounders, gastric atrophy (defined by a validated criterion, PGI <55 μg dl−1) was associated with a two-fold increased risk (OR=2.01, 95% CI: 1.18, 3.45) of OSCC in the absence of nonatrophic pangastritis (defined as PGII <11.8 μg dl−1). Stratification by PGII decreased the misclassification errors due to cancer-induced gastritis. Presence of both poor dental health, indicated by higher than median sum of decayed, missing, and filled teeth (DMFT score), and gastric atrophy further increased the risk of OSCC (OR=4.15, 95% CI: 2.04, 8.42) with relative excess risk due to interaction (RERI) of 1.47 (95% CI: −1.15, 4.1). Coexistence of poor oral hygiene habit with gastric atrophy elevated OSCC risk eight times (OR=8.65, 95% CI: 3.65, 20.46) and the additive interaction index was marginally statistically significant (RERI=4.34, 95% CI: −1.07, 9.76).
Gastric atrophy is a risk factor for OSCC, and poor dental health and oral hygiene habit may act synergistically in increasing the risk.
PMCID: PMC3425966  PMID: 22814581
atrophic gastritis; oesophageal neoplasm; relative risk; dental health; oral hygiene; pepsinogen
6.  Serum ghrelin is inversely associated with risk of subsequent oesophageal squamous cell carcinoma 
Gut  2011;61(11):1533-1537.
Oesophageal cancers rank as the eighth most common cancer and the sixth most common cause of cancer death, worldwide. Gastric atrophy, as determined by a low serum pepsinogen I/II ratio, may be associated with an increased risk of oesophageal squamous cell carcinoma (OSCC). Ghrelin, a hormone which, like pepsinogen, is produced in the fundic glands of the stomach, may be a sensitive and specific marker of gastric atrophy, but its association with OSCC is not known.
To examine the relationship between baseline serum ghrelin concentration and subsequent risk of OSCC, we conducted a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. 82 cases of OSCC were matched (1:1) by age and date of blood draw to controls from the ATBC study. Serum ghrelin was measured by radioimmunoassay. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using conditional logistic regression with adjustment for potential confounders.
For those individuals in the lowest quartile of serum ghrelin, compared to those in the highest, the multivariate odds ratio of subsequent OSCC was 6.83 (95% CI: 1.46, 31.84). These associations were dose dependent (P for trend = 0.005 for both), and independent of the effects of low pepsinogen I/II ratio (a marker of gastric fundic atrophy) and Helicobacter pylori infection. The significance of these associations remained even for individuals developing OSCC up to 10 years after baseline ghrelin measurement, though they become attenuated after 10 years.
Lower baseline concentrations of serum ghrelin were associated with an increase in risk of OSCC. Further studies are needed to confirm this finding in other populations and to explore the role of ghrelin in the aetiology of OSCC.
PMCID: PMC3462270  PMID: 22180062
ghrelin; oesophageal squamous cell carcinoma; atrophy
7.  Clinicopathological and prognostic implications of genetic alterations in oral cancers 
Oncology Letters  2011;2(3):445-451.
This study evaluated the clinicopathological and prognostic implications of genetic alterations characterizing oral squamous cell carcinoma (OSCC). Comparative genomic hybridization was used to identify chromosomal alterations present in primary OSCCs obtained from 97 patients. In this population, tobacco use was a significant risk factor for OSCC. By contrast, the 97 samples were negative for human papillomavirus (HPV) DNA integration, another known risk factor for OSCC in certain populations. Results of the Fisher’s exact test, followed by the Benjamini-Hochberg correction for multiple testing, showed a correlation of 7p gain and 8p loss with node-positive OSCC (p≤0.04 for both genetic alterations) and an association of 11q13 gain with high-grade OSCC (p≤0.05). Univariate Cox-proportional hazard models, also corrected for multiple testing, showed a significant association of 11q13 gain and 18q loss with decreased survival (p≤0.05). The findings were supported by multivariate analysis, which revealed that 11q13 gain and 18q loss together serve as a strong bivariate predictor of poor prognosis. In conclusion, our study identified genetic alterations that correlate significantly with nodal status, grade and the poor survival status of OSCC. These potential biomarkers may aid the current tumor node metastasis system for better prediction of clinical outcome.
PMCID: PMC3085881  PMID: 21546976
oral cancer; comparative genomic hybridization; prognosis; survival analysis; gain of 11q13; loss of 18q
8.  Clinicopathological and prognostic implications of genetic alterations in oral cancers 
Oncology letters  2011;2(3):445-451.
This study evaluated the clinicopathological and prognostic implications of genetic alterations characterizing oral squamous cell carcinoma(OSCC). Comparative genomic hybridization(CGH) was used to identify chromosomal alterations present in primary OSCCs obtained from 97 pateints. In this population, tobacco use was a significant risk factor for OSCC. By contrast, all 97 of our samples are negative for human papillomavirus (HPV) DNA integration, which is another known risk factor for OSCC in certain populations. Results of the Fisher’s exact test followed by Benjamini-Hochberg correction for multiple testing, showed a correlation of 7p gain and 8p loss with node-positive OSCC (p≤0.04 for both genetic alterations) and association of 11q13 gain with high-grade OSCC (p≤0.05). Univariate Cox-proportional hazard models, also corrected for multiple testing, showed significant association of 11q13 gain and 18q loss with decreased survival (p≤0.05). These findings were supported by multivariate analysis which revealed that 11q13 gain and 18q loss together serve as a strong bivariate predictor of poor prognosis. In conclusion, our study has identified genetic alterations that correlate significantly with nodal status, grade, and poor survival status of OSCC. These potential biomarkers may aid the current TNM system for better prediction of clinical outcome.
PMCID: PMC3085881  PMID: 21546976
Oral cancer; CGH; prognosis; survival analysis; gain of 11q13; loss of 18q
9.  Distinct genetic association at the PLCE1 locus with oesophageal squamous cell carcinoma in the South African population 
Carcinogenesis  2012;33(11):2155-2161.
Oesophageal squamous cell carcinoma (OSCC) has a high prevalence in the Black and Mixed Ancestry populations of South Africa. Recently, three genome-wide association studies in Chinese populations identified five new OSCC susceptibility loci, including variants at PLCE1, C20orf54, PDE4D, RUNX1 and UNC5CL, but their contribution to disease risk in other populations is unknown. In this study, we report testing variants from these five loci for association with OSCC in the South African Black (407 cases and 849 controls) and Mixed Ancestry (257 cases and 860 controls) populations. The RUNX1 variant rs2014300, which reduced risk in the Chinese population, was associated with an increased risk of OSCC in the Mixed Ancestry population [odds ratio (OR) = 1.33, 95% confidence interval (CI) = 1.09–1.63, P = 0.0055], and none of the five loci were associated in the Black population. Since PLCE1 variants increased the risk of OSCC in all three Chinese studies, this gene was investigated further by sequencing in 46 Black South Africans. This revealed 48 variants, 10 of which resulted in amino acid substitutions, and much lower linkage disequilibrium across the PLCE1 locus than in the Chinese population. We genotyped five PLCE1 variants in cases and controls, and found association of Arg548Leu (rs17417407) with a reduced risk of OSCC (OR = 0.74, 95% CI = 0.60–0.93, P = 0.008) in the Black population. These findings indicate several differences in the genetic contribution to OSCC between the South African and Chinese populations that may be related to differences in their genetic architecture.
PMCID: PMC3584964  PMID: 22865593
10.  Histological precursors of oesophageal squamous cell carcinoma: results from a 13 year prospective follow up study in a high risk population 
Gut  2005;54(2):187-192.
Background: Oesophageal squamous cell carcinoma (OSCC) has a very poor prognosis, which is largely due to late diagnosis. Successful early detection strategies will require identification of clinically relevant precursor lesions that can be targets for screening and treatment.
Aims: To identify the clinically relevant histological precursors of OSCC.
Subjects: A cohort of 682 endoscoped patients from a high risk rural population in Linxian, China.
Methods: Subjects were endoscoped and biopsied at baseline and followed for 13.5 years. We estimated the relative risk of developing OSCC for each of the initial histological diagnoses using Cox proportional hazards regression models.
Results: A total of 114 (16.7%) patients developed OSCC during the follow up period. After adjusting for potential confounding factors, relative risks (95% confidence intervals) for incidence of this tumour, by initial histological diagnosis, were: normal 1.0 (reference), oesophagitis 0.8 (0.2–3.2), basal cell hyperplasia 1.9 (0.8–4.5), mild dysplasia 2.9 (1.6–5.2), moderate dysplasia 9.8 (5.3–18.3), severe dysplasia 28.3 (15.3–52.3), and carcinoma in situ 34.4 (16.6–71.4).
Conclusions: In this study, squamous dysplasia and carcinoma in situ were the only histological lesions associated with a significantly increased risk of developing OSCC within 13.5 years after endoscopy. There was no evidence that oesophagitis predisposed to this tumour. Increasing grades of dysplasia were strongly associated with increasing risk, indicating that the histological grading was clinically meaningful. The follow up experience of severe dysplasia and carcinoma in situ was equivalent, suggesting that this distinction is not clinically relevant. Documenting these precursor lesions of OSCC should assist in the development of effective prevention, early detection, and treatment strategies for this disease.
PMCID: PMC1774842  PMID: 15647178
oesophageal cancer; precursor lesions; squamous dysplasia; China; follow up study
11.  Fractal analysis of nuclear histology integrates tumor and stromal features into a single prognostic factor of the oral cancer microenvironment 
BMC Cancer  2015;15:409.
The lack of prognostic biomarkers in oral squamous cell carcinoma (OSCC) has hampered treatment decision making and survival in OSCC remains poor. Histopathological features are used for prognostication in OSCC and, although useful for predicting risk, manual assessment of histopathology is subjective and labour intensive. In this study, we propose a method that integrates multiple histopathological features of the tumor microenvironment into a single, digital pathology-based biomarker using nuclear fractal dimension (nFD) analysis.
One hundred and seven consecutive OSCC patients diagnosed between 1998 and 2006 in Calgary, Canada were included in the study. nFD scores were generated from DAPI-stained images of tissue microarray (TMA) cores. Ki67 protein expression was measured in the tumor using fluorescence immunohistochemistry (IHC) and automated quantitative analysis (AQUA®). Lymphocytic infiltration (LI) was measured in the stroma from haematoxylin-eosin (H&E)-stained TMA slides by a pathologist.
Twenty-five (23.4%) and 82 (76.6%) patients were classified as high and low nFD, respectively. nFD was significantly associated with pathological tumor-stage (pT-stage; P = 0.01) and radiation treatment (RT; P = 0.01). High nFD of the total tumor microenvironment (stroma plus tumor) was significantly associated with improved disease-specific survival (DSS; P = 0.002). No association with DSS was observed when nFD of either the tumor or the stroma was measured separately. pT-stage (P = 0.01), pathological node status (pN-status; P = 0.02) and RT (P = 0.03) were also significantly associated with DSS. In multivariate analysis, nFD remained significantly associated with DSS [HR 0.12 (95% CI 0.02-0.89, P = 0.04)] in a model adjusted for pT-stage, pN-status and RT. We also found that high nFD was significantly associated with high tumor proliferation (P < 0.0001) and high LI (P < 0.0001), factors that we and others have shown to be associated with improved survival in OSCC.
We provide evidence that nFD analysis integrates known prognostic factors from the tumor microenvironment, such as proliferation and immune infiltration, into a single digital pathology-based biomarker. Prospective validation of our results could establish nFD as a valuable tool for clinical decision making in OSCC.
Electronic supplementary material
The online version of this article (doi:10.1186/s12885-015-1380-0) contains supplementary material, which is available to authorized users.
PMCID: PMC4435912  PMID: 25976920
12.  Short telomere lengths in peripheral blood leukocytes are associated with an increased risk of oral premalignant lesion and oral squamous cell carcinoma 
Cancer  2013;119(24):10.1002/cncr.28367.
Oral premalignant lesions (OPLs) are precursors of oral squamous cell carcinoma (OSCC). Short telomeres in peripheral blood leukocytes are associated with increased risks of several cancers. However, whether short leukocyte telomere length (LTL) predisposes to OPL and OSCC is unclear.
LTLs were measured in PBLs of 266 patients with OPL (N=174) or OSCC (N=92) at diagnosis and 394 age- and gender-matched control subjects. The association between LTL and OPL or OSCC risk, as well as the interaction of telomere length, cigarette smoking and alcohol drinking on OPL or OSCC risk were analyzed.
The age-adjusted relative LTL was the shortest in OSCC (1.64±0.29), intermediate in OPL (1.75±0.43), and longest in controls (1.82±0.36) (P for trend < 0.001). When dichotomized at the median value in controls, adjusting for age, gender, smoking and alcohol drinking status, the odds ratio (OR) for OPL and OSCC risks associated with short LTL was 2.03 (95% CI = 1.29–3.21) and 3.47 (95% CI = 1.84–6.53), respectively, with significant dose-response effects for both associations. Among 174 OPL patients, 23 progressed to OSCC and the mean LTL was shorter than in progressors than non-progressors (1.66±0.35 vs. 1.77±0.44), although the difference did not reach statistical significance (P=0.258) likely due to the small number of progressors. Interaction analysis shows that short LTL, smoking, and alcohol drinking are independent risk factors for OPL and OSCC.
Short LTL is associated with increased risks of developing OPL and OSCC and likely predisposes to the malignant progression of OPL patients.
PMCID: PMC3855186  PMID: 24105340
Telomere length; peripheral blood leukocyte; oral premalignant lesion; oral squamous cell carcinoma; smoking; alcohol drinking
13.  Prospective Study of Serum Cysteine Levels and Oesophageal and Gastric Cancers in China 
Gut  2011;60(5):618-623.
Cancers of the upper gastrointestinal tract remain a significant cause of morbidity and mortality. Cysteine, known to be involved in a myriad of immuno-modulatory, anti-oxidant, and anti-carcinogenic pathways, has not been investigated in the aetiology of oesophageal or gastric cancers. To examine the relationship between serum cysteine concentration and risk of these cancers we conducted a nested case-cohort study within the General Population Nutrition Intervention Trial in Linxian, China.
498 oesophageal squamous cell carcinomas (OSCC) and 255 gastric cardia adenocarcinomas (GCA) were matched by age and sex to 947 individuals from the wider cohort. We calculated hazard ratios (HR) and 95% confidence intervals (95% CI) using the case-cohort estimator for the Cox proportional hazards models, stratified on age and sex, with adjustment for potential confounders.
Higher concentrations of serum cysteine were significantly associated with a lower risk of both OSCC and GCA. For those in the highest quartile of serum cysteine, compared to those in the lowest, the multivariate HRs were 0.70 for OSCC (95% CI: 0.51, 0.98) and 0.59 for GCA (95% CI: 0.38, 0.91). These associations were dose dependent (P for trend = 0.006 and 0.008, respectively). These inverse associations were not significantly modified by other risk factors, with the exception of age, where a stronger association was noted among persons in the older age strata.
Higher serum concentrations of cysteine were associated with a significantly reduced risk of OSCC and GCA. Cysteine should be further investigated for its potential as a chemopreventive agent for upper gastrointestinal cancers.
PMCID: PMC3428021  PMID: 21242262
oesophageal squamous cell carcinoma; gastric cardia cancer; hazard ratio; cysteine
14.  Interaction between Alcohol Consumption and CYP 2C19 Gene Polymorphism in Relation to Oesophageal Squamous Cell Carcinoma 
PLoS ONE  2012;7(9):e43412.
The purpose of this study is to explore the relationship between the interactions of CYP2C19 gene polymorphisms and several environmental factors and oesophageal squamous cell carcinoma (OSCC).
In a case-control study of OSCC patients (n = 350) and healthy controls (n = 350), we investigated the roles of polymorphism in the CYP2C19 gene by the use of polymerase chain reaction - restriction fragment length polymorphism (PCR – RFLP) analysis.
The CYP2C19*3 AG+AA genotype was significantly more prevalent in OSCC patients (10.0% versus 3.43%; P<0.01). Multiple logistic regression analysis showed drinking (OR: 5.603, 95% CI: 3.431–11.112; P = 0.005) and smoking (OR: 4.341, 95% CI: 3.425–10.241; P = 0.001) was the independent risk factor of OSCC respectively, and there were significant interaction between CYP2C19*3 and drinking (OR: 8.747, 95% CI: 6.321–18.122; P = 0.009).
The CYP2C19*3 polymorphism and OSCC were synergistically and significantly associated in Chinese Han patients.
PMCID: PMC3439450  PMID: 22984423
15.  Elevated Serum Gas6 Is a Novel Prognostic Biomarker in Patients with Oral Squamous Cell Carcinoma 
PLoS ONE  2015;10(7):e0133940.
This study explored the level and clinical significance of serum Gas6 in patients with oral squamous cell carcinoma (OSCC).
A total of 128 OSCC patients and 145 normal controls were selected. Enzyme-linked immunosorbent assay was used to detect Gas6 concentration in sera from the OSCC patients and controls. The correlations of serum Gas6 concentration and clinicopathological characteristics of OSCC patients were assessed, and the prognostic significance of serum Gas6 was evaluated with a Kaplan–Meier curve and log-rank test.
The results showed that serum Gas6 concentration was significantly higher in OSCC patients than in controls (P < 0.05). OSCC patients with late TNM stage (III, IV) had a relatively high serum Gas6 concentration compared with those with early stage (I, II) (P < 0.01) and patients with poorly differentiated tumors had a higher level of serum Gas6 than those with well-differentiated tumors (P < 0.01). Multivariate logistic regression analysis demonstrated that high serum Gas6 was an independent risk factor for lymph nodal metastases in OSCC patients (OR = 2.79, 95% CI: 1.72–4.48). For predicting OSCC development, ROC curve analysis showed a sensitivity of 0.63 with a specificity of 0.92 (AUC = 0.79, 95% CI: 0.74–0.85). Cox analysis revealed that high serum Gas6 was an independent biomarker for predicting poor overall survival in OSCC patients (HR = 2.07, 95% CI: 1.79–3.62). In addition, we found that Gas6 expression was increased in OSCC tissues and it may significantly decrease E-cadherin expression, and increase P-cadherin and N-cadherin expression, in OSCC cells. Further, Gas6 could promote the migratory and invasive ability of OSCC cells in vitro.
Taken together, these results suggest that Gas6 increases the metastatic capacity of OSCC cells and serum Gas6 could be a candidate biomarker for diagnostic and prognostic use in OSCC patients.
PMCID: PMC4514879  PMID: 26207647
16.  A history of allergies is associated with reduced risk of oral squamous cell carcinoma 
Cancer causes & control : CCC  2012;23(12):1911-1919.
A history of allergies is associated with a decreased risk of several types of cancers. Potential mechanisms include enhanced immune surveillance against tumor cells early in disease development and/or carcinogenic infectious agents. We tested whether allergies are inversely associated with oral squamous cell carcinoma (OSCC), accounting for factors that may modify the association, such as tumor site, stage, and HPV infection.
We estimated odds ratios (OR) and 95% confidence intervals (CI) for the association between allergy history (including different types of allergies) and OSCC, adjusted for potential confounders, among 400 cases and 613 controls. Analyses were also stratified by site, stage, and measures of HPV infection.
We observed a weak inverse association between history of any allergy and OSCC (OR=0.81, 95% CI, 0.61–1.08). This association was present only for allergies to airborne allergens (dust/pollen/mold); OR=0.67; 95% CI, 0.48–0.93. The inverse associations with airborne allergies were slightly stronger for oropharyngeal SCC (OR=0.56; 95% CI, 0.35–0.90) than for oral cavity SCC (OR=0.71; 95% CI, 0.49–1.05), and present only for later stage cancers (OR=0.42; 95% CI, 0.26–0.66) as opposed to earlier stage cancers (OR=0.98; 95% CI, 0.66–1.46). Inverse associations were not particularly present or stronger among HPV-16 seropositive individuals or for HPV DNA positive OSCC.
There is an inverse association between history of allergies to dust, pollen or mold and OSCC. Whether the inverse association involves heightened immune surveillance, increased immune response to HPV or other antigen, or other carcinogenic mechanism, remains to be determined in more definitive studies.
PMCID: PMC3499679  PMID: 23011537
allergies; oral squamous cell carcinoma; HPV; HSV
17.  Association of interleukin-6 genetic polymorphisms with risk of OSCC in Indian population 
Meta Gene  2015;4:142-151.
Interleukin-6 (IL-6) encodes a cytokine protein, which causes inflammation, maintains immune homeostasis and plays an essential role in oral pathogenesis. The aim of this study was to evaluate the association between IL-6 (− 174 and − 572) G/C promoter gene polymorphisms and risk of OSCC among Indians.
Single nucleotide polymorphism in IL-6 genes was genotyped in OSCC patients and healthy controls by PCR-RFLP method. Genotype and allele frequencies were analyzed by chi-square test and strength of associations by odds ratio with 95% confidence intervals.
Frequency distribution of IL-6 (− 174) G/C gene polymorphism was significantly associated with OSCC patients in comparison to healthy controls (OR: 0.541, CI: 0.356–0.822; p: 0.004. However, frequency of IL-6 (− 572) G/C gene polymorphism was not significantly associated with OSCC patients (p > 0.05).
The genotype GC and allele C of IL-6 (− 174) G/C gene polymorphism play a significant role in OSCC susceptibility.
•We first demonstrate the IL-6 polymorphism in OSCC patients in Indian population.•We obtained the SNP of IL-6 (-174) is increase the risk of OSCC.•We also obtained the SNP of IL-6 (-572) and risk of OSCC•We evaluate the correlation of these IL-6 polymorphisms and progression of OSCC.•We identified the environmental factors and gene interactions with pathogenesis of OSCC.
PMCID: PMC4436510  PMID: 26005639
OSCC; Inflammation; Immune response; Genotype; PCR-RFLP
18.  The 341C/T polymorphism in the GSTP1 gene is associated with increased risk of oesophageal cancer 
BMC Genetics  2010;11:47.
The Glutathione S-transferases (GSTs) comprise a group of enzymes that are critical in the detoxification of carcinogens. In this study the effects of polymorphisms in these genes on the risk of developing oesophageal squamous cell carcinoma (OSCC) were evaluated in a hospital-based case-control study in two South African population groups. Genetic polymorphisms in GSTs were investigated in 245 patients and 288 controls samples by PCR-RFLP analysis.
The GSTP1 341T variant was associated with significantly increased risk of developing OSCC as observed from the odds ratios for the GSTP1 341C/T and GSTP1 341T/T genotypes (OR = 4.98; 95%CI 3.05-8.11 and OR = 10.9; 95%CI 2.43-49.1, respectively) when compared to the homozygous GSTP1 341C/C genotype. The risk for OSCC in the combined GSTP1 341C/T and T/T genotypes was higher in tobacco smokers (OR = 7.51, 95% CI 3.82-14.7), alcohol consumers (OR = 15.3, 95% CI 1.81-12.9) and those using wood or charcoal for cooking and heating (OR = 12.1, 95% CI 3.26-49) when compared to those who did not smoke tobacco, or did not consume alcohol or user other forms of fuel for cooking and heating. Despite the close proximity of the two GSTP1 SNPs (313A>G and 341C>T), they were not in linkage disequilibrium in these two population groups (D':1.0, LOD: 0.52, r2: 0.225). The GSTP1 313A/G polymorphism on the other hand, did not display any association with OSSC. The homozygous GSTT1*0 genotype was associated with increased risk of OSCC (OR = 1.71, 95%CI 1.18-2.46) while the homozygous GSTM1*0 genotype was associated with significantly decreased risk of OSCC in the Mixed Ancestry subjects (OR= 0.39, 95%CI 0.25-0.62).
This study shows that the risk of developing OSCC in the South African population can be partly explained by genetic polymorphisms in GST coding genes and their interaction with environmental factors such as tobacco smoke and alcohol consumption.
PMCID: PMC2891604  PMID: 20540773
19.  Caspase-8 polymorphisms and risk of oral squamous cell carcinoma 
Caspase-8 (CASP8) is a key controller of apoptosis, and its deregulation is crucially involved in carcinogenesis. The aim of the present study was to evaluate the function of CASP8 polymorphisms in oral squamous carcinoma (OSCC) by evaluating the risk associated with three single-nucleotide polymorphisms (SNPs) in a case-control study in a Han Chinese patient population. A total of 505 individuals with clinically diagnosed OSCC and 507 healthy controls were tested for the three SNPs rs3834129, rs13016963 and rs1045485, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing analysis. After adjusting for other confounders, the genotype frequencies of CASP8 −652 6N ins/del promoter polymorphism (rs3834129) were found to be lower in patients with OSCC compared with normal subjects. No significant difference was detected in the genotype frequencies of rs13016963 between the patients and control subjects. However, the AA genotype frequency of rs1306963 was associated with OSCC as a risk factor among non-smokers and non-drinkers. For CASP8, rs1045485 was not present in any of the patients with OSCC or control subjects. These results suggest that the del allele of rs3834129 may play a protective role in the tumorigenesis of OSCC and may be useful as a genetic susceptibility marker for OSCC in the population studied.
PMCID: PMC4665542  PMID: 26668627
oral squamous carcinoma; caspase-8; single nucleotide polymorphisms; Chinese population
20.  Oesophageal squamous cell carcinoma may develop within a background of accumulating DNA methylation in normal and dysplastic mucosa 
Gut  2006;56(1):13-19.
Oesophageal squamous cell carcinoma (OSCC) often arises from preceding dysplastic lesions in the oesophageal epithelium. However, the molecular changes occurring in premalignant lesions are not well understood. An epigenetic change is an example of OSCC that may occur within the epithelium.
To investigate the methylation status of multiple promoters in cancer‐derived DNA, as well as in the background epithelium of OSCC, including dysplastic lesions and non‐neoplastic mucosa. The normal epithelium from patients without cancer was also examined. The findings were correlated with the mutational status of p53.
Patients and methods
56 patients with advanced OSCC, 21 patients with intraepithelial neoplasia (IEN), 56 patients with a background of non‐neoplastic epithelium, adjacent to the OSCC, and 42 normal control epithelia from healthy volunteers were studied. The promoter methylation status of SFRP1, SFRP2, DCC, APC, p16INK4a, p14ARF, MINT1, MINT2, MINT31, CACNA1G, COX2, DAPK, hMLH1 and MGMT was examined by methylation‐specific single polymerase chain reaction or combined bisulphite restriction analysis. The mutation of p53 by direct sequencing was assessed.
DNA methylation was observed in OSCC and in its background epithelium. The frequency of CpG island methylation increased from a baseline level in the background non‐neoplastic epithelium, through IEN, to advanced OSCC. However, mutations in p53 were almost exclusively observed in IEN and OSCC. More extensive DNA methylation was seen in the neoplastic lesions (OSCC or IEN) having a p53 mutation than in those with wild‐type p53.
DNA methylation is present at low levels in the non‐neoplastic oesophageal epithelium and appears to contribute to the progression of the dysplasia–carcinoma sequence in OSCC carcinogenesis.
PMCID: PMC1856655  PMID: 16785283
21.  Elevated plasma level of visfatin/pre-b cell colony-enhancing factor in male oral squamous cell carcinoma patients 
Objectives: Visfatin, also known as nicotiamide phosphoribosyltransferase or pre-B cell colony enhancing factor, is a pro-inflammatory cytokine whose serum level is increased in various cancers. In this study, we investigated whether plasma visfatin levels were altered in patients with oral squamous cell carcinoma (OSCC). The relationship between plasma visfatin levels and the pretreatment hematologic profile was also explored. Study Design: Plasma visfatin concentrations were measured through ELISA in OSCC patients and control subjects. A total of 51 patients with OSCC and 57 age- and body mass index (BMI)-matched control subjects were studied. All study subjects were male. Results: Plasma visfatin was found to be elevated in patients with OSCC (7.0 ± 4.5 vs. 4.8 ± 1.9 ng/ml, p = 0.002). Multiple logistic regression analysis revealed visfatin as an independent association factor for OSCC, even after full adjustment of known biomarkers. Visfatin level was significantly correlated with white blood cell (WBC) count, neutrophil count, and hematocrit (all p < 0.05). In addition, WBC count, neutrophil count, and visfatin gradually increased with stage progression, and hematocrit gradually decreased with stage progression (all p < 0.05). Conclusion: Increased plasma visfatin levels were associated with OSCC, independent of risk factors, and were correlated with inflammatory biomarkers. These data suggest that visfatin may act through inflammatory reactions to play an important role in the pathogenesis of OSCC.
Key words:Visfatin; oral squamous cell carcinomas; white blood cell count; neutrophil count.
PMCID: PMC3613867  PMID: 23229270
22.  Effects of EZH2 promoter polymorphisms and methylation status on oral squamous cell carcinoma susceptibility and pathology 
American Journal of Cancer Research  2015;5(11):3475-3484.
Oral squamous cell carcinoma (OSCC), which is malignant tumors in oral cavity, is the fourth most common male cancer in Taiwan. EZH2 plays a key role in transcriptional repression through chromatin remodeling and in cancer development. Although the EZH2 expression in OSCC is highly correlated with tumorigenesis, it has not been determined if specific EZH2 genetic variants are associated with OSCC risk. The aim of this study was to investigate the relationship between genetic polymorphisms of EZH2 and susceptibility to OSCC in Taiwan. Here, four SNPs of EZH2 (rs6950683, rs2302427, rs3757441, and rs41277434) were analyzed by a real-time PCR genotyping in 576 patients with oral cancer and 552 cancer-free controls. After adjusting for other co-variants, we found that carrying CC genotype at EZH2 rs6950683 and rs3757441 had a lower risk of developing OSCC than did wild-type carriers. The CCCA or CCTA haplotype among the four EZH2 sites was also associated with a reduced risk of OSCC. Furthermore, OSCC patients who carried CC genotype at EZH2 rs6950683 had a higher methylation than TC genotype. Our results suggest that the two SNPs of EZH2 (rs6950683 and rs3757441) might contribute to the prediction of OSCC susceptibility. Moreover, rs6950683 CC genotype exhibits hypermethylation in EZH2 promoter. This is the first study to provide insight into risk factors associated with EZH2 variants and epigenetic changes in carcinogenesis of OSCC in Taiwan.
PMCID: PMC4697693  PMID: 26807327
EZH2; oral squamous cell carcinoma; single-nucleotide polymorphism (SNP); bisulfite sequencing; methylation
23.  Associations between proteasomal activator PA28γ and outcome of oral squamous cell carcinoma: Evidence from cohort studies and functional analyses 
EBioMedicine  2015;2(8):851-858.
PA28γ was suggested to play a role in malignant progression. This paper aimed to investigate the association between PA28γ and the prognosis of oral squamous cell carcinoma (OSCC) in cohort studies.
The PA28γ expression level was assessed by immunohistochemistry in a total of 368 OSCC patients from three independent cohorts. The Cox proportional hazards regression model was used to determine multivariate hazard ratios for Overall Survival (OS). Model discrimination was measured using C Statistic. Additionally, OS was analyzed in Head Neck Squamous Cell Carcinoma (HNSCC) patients from The Cancer Genome Atlas (TCGA) data set. Functional analyses were conducted both in-vitro and in-vivo.
The median follow-up times of patients in the three studies were 60, 52, and 51 months. High expression of PA28γ was identified in tumors from 179 of 368 patients (48.6%). Compared with low expression, high expression of PA28γ was strongly associated with worse OS, with relative risks of 5.14 (95% CI, 2.51–10.5; P < 0.001), 2.82 (95% CI, 1.73–4.61; P < 0.001), and 3.85 (95% CI, 1.59–9.37; P = 0.003). PA28γ expression was also associated with disease-free survival in all three cohorts (P < 0.005). These findings are consistent with TCGA HNSCC data (P < 0.006). The prediction of all-cause mortality was significantly improved when PA28γ was added to the traditional clinical factors (Model 3, C statistic value: 0.78 VS 0.73, P = 0.016). In functional analyses, we found that PA28γ silencing dramatically inhibited the growth, proliferation and mobility of OSCC cells in vitro and reduced tumor growth and angiogenesis in tumor-bearing mice.
PA28γ overexpression is associated with adverse prognosis in patients with OSCC. The aberrant expression of PA28γ may contribute to the pathogenesis and progression of OSCC.
Research in context
OSCC is one of the most common HNSCC, which have a high lethally rate. However, few prognostic markers have been applied in the clinical practice. We found that PA28γ in OSCC tumor tissues were significantly high expression than those in normal tissues. As the results of the three cohorts from two independent research centers and from an additional validation cohort from a US population in the TCGA dataset, we demonstrate PA28γ is a good predictor of the risk of death in OSCC. Meanwhile, we demonstrate PA28γ have a potential role in OSCC tumorigenesis.
•PA28γ protein over-expressed in a large subset of patients with OSCC•PA28γ was a prognostic factor in OSCC based on the results of three cohorts in China•The analysis of PA28γ mRNA abundance in a US/non-Chinese cohort from TCGA dataset consistent with Chinese-cohort study•PA28γ silencing could affect the tumor biological behavior of OSCC both in vitro and vivo.
PMCID: PMC4563126  PMID: 26425691
PA28γ; OSCC; Prognosis; Carcinogenesis
24.  Integrative analysis of DNA copy number and gene expression in metastatic oral squamous cell carcinoma identifies genes associated with poor survival 
Molecular Cancer  2010;9:143.
Lymphotropism in oral squamous cell carcinoma (OSCC) is one of the most important prognostic factors of 5-year survival. In an effort to identify genes that may be responsible for the initiation of OSCC lymphotropism, we examined DNA copy number gains and losses and corresponding gene expression changes from tumor cells in metastatic lymph nodes of patients with OSCC.
We performed integrative analysis of DNA copy number alterations (CNA) and corresponding mRNA expression from OSCC cells isolated from metastatic lymph nodes of 20 patients using Affymetrix 250 K Nsp I SNP and U133 Plus 2.0 arrays, respectively. Overall, genome CNA accounted for expression changes in 31% of the transcripts studied. Genome region 11q13.2-11q13.3 shows the highest correlation between DNA CNA and expression. With a false discovery rate < 1%, 530 transcripts (461 genes) demonstrated a correlation between CNA and expression. Among these, we found two subsets that were significantly associated with OSCC (n = 122) when compared to controls, and with survival (n = 27), as tested using an independent dataset with genome-wide expression profiles for 148 primary OSCC and 45 normal oral mucosa. We fit Cox models to calculate a principal component analysis-derived risk-score for these two gene sets ('122-' or '27-transcript PC'). The models combining the 122- or 27-transcript PC with stage outperformed the model using stage alone in terms of the Area Under the Curve (AUC = 0.82 or 0.86 vs. 0.72, with p = 0.044 or 0.011, respectively).
Genes exhibiting CNA-correlated expression may have biological impact on carcinogenesis and cancer progression in OSCC. Determination of copy number-associated transcripts associated with clinical outcomes in tumor cells with an aggressive phenotype (i.e., cells metastasized to the lymph nodes) can help prioritize candidate transcripts from high-throughput data for further studies.
PMCID: PMC2893102  PMID: 20537188
25.  Integrative Genomics in Combination with RNA Interference Identifies Prognostic and Functionally Relevant Gene Targets for Oral Squamous Cell Carcinoma 
PLoS Genetics  2013;9(1):e1003169.
In oral squamous cell carcinoma (OSCC), metastasis to lymph nodes is associated with a 50% reduction in 5-year survival. To identify a metastatic gene set based on DNA copy number abnormalities (CNAs) of differentially expressed genes, we compared DNA and RNA of OSCC cells laser-microdissected from non-metastatic primary tumors (n = 17) with those from lymph node metastases (n = 20), using Affymetrix 250K Nsp single-nucleotide polymorphism (SNP) arrays and U133 Plus 2.0 arrays, respectively. With a false discovery rate (FDR)<5%, 1988 transcripts were found to be differentially expressed between primary and metastatic OSCC. Of these, 114 were found to have a significant correlation between DNA copy number and gene expression (FDR<0.01). Among these 114 correlated transcripts, the corresponding genomic regions of each of 95 transcripts had CNAs differences between primary and metastatic OSCC (FDR<0.01). Using an independent dataset of 133 patients, multivariable analysis showed that the OSCC–specific and overall mortality hazards ratio (HR) for patients carrying the 95-transcript signature were 4.75 (95% CI: 2.03–11.11) and 3.45 (95% CI: 1.84–6.50), respectively. To determine the degree by which these genes impact cell survival, we compared the growth of five OSCC cell lines before and after knockdown of over-amplified transcripts via a high-throughput siRNA–mediated screen. The expression-knockdown of 18 of the 26 genes tested showed a growth suppression ≥30% in at least one cell line (P<0.01). In particular, cell lines derived from late-stage OSCC were more sensitive to the knockdown of G3BP1 than cell lines derived from early-stage OSCC, and the growth suppression was likely caused by increase in apoptosis. Further investigation is warranted to examine the biological role of these genes in OSCC progression and their therapeutic potentials.
Author Summary
Neck lymph node metastasis is the most important prognostic factor in oral squamous cell carcinoma (OSCC). To identify genes associated with this critical step of OSCC progression, we compared DNA copy number aberrations and gene expression differences between tumor cells found in metastatic lymph nodes versus those in non-metastatic primary tumors. We identified 95 transcripts (87 genes) with metastasis-specific genome abnormalities and gene expression. Tested in an independent cohort of 133 OSCC patients, the 95 gene signature was an independent risk factor of disease-specific and overall death, suggesting a disease progression phenotype. We knocked down the expression of over-amplified genes in five OSCC cell lines. Knockdown of 18 of the 26 tested genes suppressed the cell growth in at least one cell line. Interestingly, cell lines derived from late-stage OSCC were more sensitive to the knockdown of G3BP1 than cell lines derived from early-stage OSCC. The knockdown of G3BP1 increased programmed cell death in the p53-mutant but not wild-type OSCC cell lines. Taken together, we demonstrate that CNA–associated transcripts differentially expressed in carcinoma cells with an aggressive phenotype (i.e., metastatic to lymph nodes) can be biomarkers with both prognostic information and functional relevance. Moreover, results suggest that G3BP1 is a potential therapeutic target against late-stage p53-negative OSCC.
PMCID: PMC3547824  PMID: 23341773

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