Nebojsa Jovic

Gene hypermethylation in tumor tissue of advanced oral squamous cell carcinoma patients.

Oral squamous cell carcinoma (OSCC) is characterized by high mortality rate and rising incidence. The aim of this study was to examine the methylation of particular tumor suppressor genes promoters in OSCC and to correlate the methylation status with the tumor-host features and patients survival. The genes selected for our investigation are involved in key cellular processes of malignant transformation, including cell cycle control (p16), apoptosis (Death Associated Protein Kinase, DAPK), Wnt signaling (Adenomatous Polyposis Coli, APC), cell-cell adhesion (E-cadherin, E-cad), and DNA repair (O(6)-methylguanine-DNA methyltransferase, MGMT, Werner syndrome gene, WRN). In 77 patients with OSCC, hypermethylation was determined by nested methylation-specific PCR method. Methylation of p16 gene promoter was detected in 58.4% of samples, E-cad in 42.9%, DAPK in 36.8%, MGMT in 33.8%, WRN in 23.8%, and APC in 18.2% of OSCC samples. Patients with E-cad promoter methylation had significantly worse overall survival (p=0.039, log-rank test), while hypermethylation of other genes did not have prognostic significance. Stratified analysis by the lymph node involvement and tumor stage showed that E-cad promoter methylation is associated to poor survival in N positive (p=0.024), and stage III tumors (p=0.027), as an opposite to N0 and stage II tumors, where E-cad methylation did not have prognostic significance (p=0.849, p=0.794, respectively). Our findings indicate that multiple genes are frequently aberrantly methylated in OSCC, and that E-cad promoter methylation should be considered as a potential molecular marker for the poor survival in advanced OSCC.

Prognostic significance of tumor-related genes hypermethylation detected in cancer-free surgical margins of oral squamous cell carcinomas

Oral squamous cell carcinoma (OSCC) is characterized by high mortality rates. High incidence of local recurrences in the normal-appearing surgical margins of OSCC patients indicates the existence molecular alterations, including DNA methylation, which could not be detectable by histopathologic analysis. The objective of our study was to determine correlation of tumor-related genes hypermethylation detected in histopathologically negative surgical margins with clinical and prognostic parameters. The genes selected for methylation analysis covered a wide range cellular processes including cell cycle control (p16), apoptosis (DAPK and RASSF1A), Wnt signaling (APC, WIF1 and RUNX3), cell-cell adhesion (E-cad), and DNA repair (MGMT and hMLH1). All of 47 patients had histologically confirmed negative surgical margins. For each of patient, samples from primary malignant tissue and the two consecutive surgical margins were taken at the time of surgery. DNA methylation was determined by multiplex nested methylation-specific PCR. Twenty-seven patients were margin-positive for promoter hypermethylation of at least one gene under study. The presence of DAPK promoter hypermethylation detected in surgical margins was associated with the decreased overall survival (p=0.004, log rank test). Multivariate analysis revealed that DAPK promoter hypermethylation in surgical margins is an independent prognostic factor for overall survival, HR=4.105 (1.458-11.555, 95% CI, p=0.007). Hypermethylation of other tumor-related genes under study did not have prognostic significance. These results demonstrate that DNA hypermethylation in histologically negative surgical margins is a frequent event. Promoter hypermethylation of DAPK gene detected in surgical margins may be a useful molecular marker for the poor survival in OSCC patients. Further investigation into the therapeutic potential of these findings in OSCC is warranted.

Vitamin D receptor, CYP27B1 and CYP24A1 genes polymorphisms association with oral cancer risk and survival.

BACKGROUND Genetic polymorphisms of vitamin D receptor gene (VDR) and genes involved in vitamin D metabolism pathway, CYP27B1 and CYP24B1, may affect individual susceptibility to oral squamous cell carcinoma. The purpose of this study was to evaluate the associations between VDR, CYP27B1 and CYP24A1 gene polymorphisms with oral cancer risk and survival. METHODS Study cohort consisted of 110 patients with oral cancer and 122 healthy controls. The genotypes of the analysed genes were determined by PCR-RFLP or real-time PCR method. RESULTS The significant decrease of oral cancer risk was observed in individuals with heterozygote genotype of CYP24A1 gene (rs2296241) (odds ratio 0.281, P = 0.000) in comparison with wild type. Patients with VDR FokI ff wild type genotype had significantly worse overall survival (P = 0.012, log rank) compared with heterozygous and mutated genotype combined. A stratified analysis by the lymph node involvement and tumour stage showed that ff is associated with poor survival in groups with and without lymph node involvement (P = 0.025, P = 0.040, respectively) and in stage III tumours (P = 0.026). Multivariate Coxs regression analysis revealed that VDR FokI could be considered an independent prognostic factor. CONCLUSION Our findings indicate that CYP24A1 gene polymorphism might have an influence on the susceptibility to oral cancer. VDR FokI polymorphism was associated with worse survival and could be considered as an independent prognostic marker.

Interaction between the MTHFR C677T Polymorphism and Alcohol—Impact on Oral Cancer Risk and Multiple DNA Methylation of Tumor-related Genes:

Several studies have reported Oral Squamous Cell Carcinoma (OSCC) association with etiological factors, such as smoking and alcohol. The aim of the present study was to establish whether the methylenetetrahydrofolate reductase (MTHFR) C677T genotype and a high alcohol intake, solely or in interaction, have an impact on the oral cancer risk, DNA methylation, or multiple methylation of tumor-related genes. MTHFR C677T genetic polymorphism was determined by the PCR/RFLP method, and DNA methylation was assessed by nested methylation-specific PCR. The risk for multiple methylation was significantly increased in heavy-drinking patients with the TT genotype, compared with CC and CT patients (OR = 10.873; 95% CI, 1.134-104.24). Multiple methylation was significantly associated with tumor stage (p = 0.018), and showed a trend of association with the presence of nodal metastases (p = 0.058). A significant association was found between TT genotype and methylation status of the RASSF1A gene in OSCC patients (p = 0.012). Heavy-drinking individuals with the TT genotype showed increased oral cancer risk compared with the CC genotype (OR = 3.601; 95% CI, 1.036-12.513), and compared with the CC and CT genotypes (OR = 4.288; 95% CI, 1.325-13.877). Our study suggested gene-environment interactions between high alcohol intake and the MTHFR 677TT genotype for elevated oral cancer risk, with a significant impact on multiple methylation of cancer-related genes.

Association of VEGF-A genetic polymorphisms with cancer risk and survival in advanced-stage oral squamous cell carcinoma patients

BACKGROUND Vascular endothelial growth factor (VEGF), a key mediator of angiogenesis, is overexpressed in a wide variety of human cancers, including oral squamous cell carcinoma (OSCC). In this study, we examined whether individual polymorphisms within VEGF-A gene, rs699947 (-2578C/A), rs1570360 (-1154G/A), rs2010963 (-634G/C), rs3025039 (+936C/T) or their haplotypes are associated with an oral cancer risk and survival. METHODS A case-control study was conducted on 114 OSCC patients and control group of 126 individuals without a previous cancer history, all the Caucasian race and the same ethnicity, matched by age and gender. VEGF-A genotypes were analyzed using TaqMan SNP Genotyping Assays, Applied Biosystems. RESULTS The -1154 GG genotype was significantly associated with the decreased overall survival in OSCC patients (p = 0.010, log rank test). Stratified analysis revealed that in patients with nodal metastases and stage III, -1154 GG genotype was related to worse survival, p = 0.009, p = 0.013, respectively. The multivariate analysis revealed that -1154 GG genotype is an independent adverse factor for survival in the OSCC (HR = 1.899, [1.138-3.168], p = 0.014). The +936 CC genotype was associated with advanced staged OSCC (p = 0.050). The three polymorphisms, -2578, -1154 and -634 were in linkage disequilibrium (LD). The CAG haplotype could be associated with an increased oral cancer risk, OR = 7.967, [1.730-36.689], p = 0.008, while CGG haplotype could be associated with a decreased oral cancer risk, OR = 0.561, [0.326-0.964], p = 0.036. CONCLUSIONS VEGF-A -1154 GG genotype could be considered as a prognostic marker of poor survival in advanced-stage OSCC patients. Haplotypes of VEGF-A gene may be associated with susceptibility to OSCC.

Association of TLR2, TLR3, TLR4 and CD14 genes polymorphisms with oral cancer risk and survival

OBJECTIVES The aim of this study is to investigate association between polymorphisms in TLR2, TLR3, TLR4 and CD14 genes or their haplotypes with oral squamous cell carcinomas (OSCC) risk and survival. METHODS The study was conducted on 93 OSCC patients and 104 cancer-free controls. Polymorphisms were genotyped by real-time PCR or PCR-RFLP method. RESULTS Significant increase in oral cancer risk was observed in individuals with mutated genotype of TLR3 rs3775291 polymorphism (OR = 1.096, P = 0.036) compared to wild-type. The heterozygous and mutated genotype of TLR3 rs5743312 polymorphism had worse survival in group of patients with stage III tumours (P = 0.043). Multivariate Cox regression analysis revealed that TLR3 rs5743312 polymorphism could be considered as prognostic marker in advanced III stage OSCC (HR = 2.456, P = 0.007), but not independently of nodal status. TLR3 rs3775291 and rs5743312 polymorphisms were in strong linkage disequilibrium. Haplotype TG was associated with worse prognosis in OSCC patients in comparison with common CG haplotype (HR = 1.717, P = 0.042). Interaction among polymorphisms in TLR2, TLR3 and CD14 genes was observed (P = 0.010). CONCLUSIONS TLR3 rs5743312 polymorphism could be considered as potential predictor of worse overall survival in advanced oral cancer, but not independently of nodal status. Haplotypes in TLR3 gene might be associated with poor prognosis in OSCC patients.

Hypermethylation of RUNX3 but not WIF1 gene and its association with stage and nodal status of tongue cancers

OBJECTIVES Recent studies indicate various molecular abnormalities in oral squamous cell carcinomas (OSCC), including DNA methylation of tumor-associated genes. Although promoter hypermethylation of Wnt pathway antagonists RUNX3 (Runt-related transcription factor 3) and Wnt inhibitory factor 1 (WIF1) has been identified as a common event in a number of carcinomas, methylation status and the role of RUNX3 as a possible tumor suppressor in oral and head and neck cancer are yet controversial. The aim of our study is to determine the occurrence of RUNX3 and WIF1 genes hypermethylation and correlation with tumor and host-related factors and prognosis in tongue carcinomas. MATERIAL AND METHODS In 76 patients with tongue carcinoma, RUNX3 and WIF1 genes promoter hypermethylation analysis was assessed by nested methylation-specific PCR method. RESULTS Hypermethylation of WIF1 and RUNX3 genes promoters was observed in 35% and 25% of carcinomas, respectively. RUNX3 gene promoter hypermethylation was significantly associated with lymph node involvement (P = 0.013) and tumor stage (P = 0.006), but not with the overall survival. Occurrence of RUNX3 and WIF1 genes comethylation was associated with nodal status (P = 0.058) and tumor stage (P = 0.055). CONCLUSIONS Our findings indicate that RUNX3 and WIF1 are frequently aberrantly methylated and that RUNX3 promoter methylation could be considered as a potential prognostic marker in tongue carcinoma.

HMGB1 genetic polymorphisms in oral squamous cell carcinoma and oral lichen planus patients

OBJECTIVES This study examined the single nucleotide polymorphisms (SNPs) in high-mobility group box 1 (HMGB1) gene in patients with oral squamous cell carcinoma (OSCC) and oral lichen planus (OLP). MATERIALS AND METHODS The study was conducted on 93 patients with OSCC, 53 patients with OLP, and 100 controls, all Caucasians of the same ethnicity, matched by age. HMGB1 genotypes for 4 SNPs, 2262G/A (rs1045411), 1177G/C (rs3742305), 3814C/G (rs2249825), and rs4540927, were assessed using TaqMan SNP Genotyping Assays, Applied Biosystems. RESULTS The HMGB1 1177GG genotype was associated with lymph-node metastasis and tumor stage in OSCCs (P = 0.016 and P = 0.030, respectively). Genotype 1177GG resulted in poorer recurrence-free survival (RFS), P = 0.000. The 1177G/C polymorphism was an independent predictor of RFS compared to GG genotype, P = 0.001. The three polymorphisms were in linkage disequilibrium (LD). The AGC and GGC haplotypes were associated with an increased oral cancer risk, determined over the haplotype odds ratios (HOR = 13.316, P = 0.015, and HOR = 5.769, P = 0.029, respectively). The AGC haplotype was related to erosive OLP progression to OSCC (HOR = 12.179, P = 0.001). CONCLUSIONS HMGB1 polymorphism 1177G/C could be associated with tumor progression and recurrence-free survival in patients with OSCC. The haplotypes of HMGB1 gene might be associated with susceptibility to OSCC and OLP progression to OSCC.

Genetic Polymorphisms of ADH1C and CYP2E1 and Risk of Oral Squamous Cell Carcinoma

Objective. Several studies have suggested that the metabolism of alcohol is modulated by the polymorphisms in genes encoding ethanol-metabolizing enzymes, including alcohol dehydrogenase 1C, ADH1C, and cytochrome P450-dependent monooxygenase, CYP2E1. Genetic polymorphisms of ethanol-metabolizing enzymes may affect individual susceptibility to oral cancer. The purpose of this study was to investigate the associations between ADH1C and CYP2E1 gene polymorphisms with oral squamous cell carcinoma in an ethnically homogeneous Caucasian population. Design. Case-control study. Setting. Serbian national general hospital. Subjects and Methods. The study was conducted on 123 oral cancer patients and a control group of 177 individuals of the Caucasian race and the same ethnicity, matched in age and gender, without previous cancer history. The control group consisted of 120 population-based and 57 hospital-based controls of heavy-drinking individuals. Genetic polymorphisms of ADH1C SspI, ADH1C HaeIII, CYP2E1 RsaI, and CYP2E1 Ins were determined by the polymerase chain reaction and restriction fragment length polymorphisms. Results. After adjustment by potential confounders, the significant increase of oral cancer risk, independent of alcohol drinking, was observed in individuals with the variant ADH1C SspI*2/*2 genotype (odds ratio, 3.029; P = .014) and in combined ADH1C SspI*1/*2 and ADH1C SspI*2/*2 genotypes (odds ratio, 2.605; P = .002), compared to the ADH1C*1/1* wild type. The association of other polymorphisms under study was not observed. Conclusion. This study suggested that the ADH1C SspI polymorphism could play a significant role in the etiology of oral cancer, whereas ADH1C HaeIII, CYP2E1 RsaI, and CYP2E1 Ins could have minor influence.

Temporomandibular disorders after orthognathic surgery in patients with mandibular prognathism with depression as a risk factor

OBJECTIVE To examine the prevalence of temporomandibular disorders (TMD) after orthodontic-surgical treatment in patients with mandibular prognathism and analyze psychosocial variables related to TMD. MATERIALS AND METHODS The case-control study comprised 40 patients with mandibular prognathism who underwent combined orthodontic-surgical treatment (orthognathic surgery group). Forty-two patients with untreated mandibular prognathism served as a control group. Research diagnostic criteria for temporomandibular disorders was used in order to assess the clinical diagnosis of TMD (Axis I) and to estimate depression, somatization and patients disability related to chronic pain (Axis II). RESULTS The overall prevalence of TMD was not significantly different between the groups. Myofascial pain was significantly higher, while arthralgia, arthritis and arthrosis was significantly lower in the orthognathic group compared with the controls (90.5% vs 50.0%, 0.0% vs 27.8%, respectively) (p < 0.05). Females in orthognathic surgery group showed higher prevalence of TMD (p < 0.05) and myofascial pain (p < 0.01) and increased level of chronic pain (p < 0.05) in comparison with post-operative males. No significant difference in chronic pain, somatization and depression scores was found between investigated groups. With respect to presence of TMD within the groups depression was higher in untreated subjects with dysfunction (p < 0.05). CONCLUSION Prevalence of TMD immediately after completion of orthodontic-surgical treatment for mandibular prognathism is similar to frequency of dysfunction in untreated subjects, is significantly higher in females and is most commonly myogenic. Furthermore, females show an increased level of chronic pain post-operatively. Somatization and depression levels do not differ between patients with corrected prognathism and untreated prognathic patients.