Effect of ZEB1 Associated with microRNAs on Tumor Stem Cells in Head and Neck Cancer.

Cancer biologists have focused on studying cancer stem cells (CSCs) because of their ability to self-renew and recapitulate tumor heterogeneity, which increases their resistance to chemotherapy and is associated with cancer relapse. Here, we used two approaches to isolate CSCs: the first involved the metabolic enzyme aldehyde dehydrogenase ALDH, and the second involved the three cell surface markers CD44, CD117, and CD133. ALDH cells showed a higher zinc finger E-box binding homeobox 1 (ZEB1) microRNA (miRNA) expression than CD44/CD117/133 triple-positive cells, which overexpressed miRNA 200c-3p: a well-known microRNA ZEB1 inhibitor. We found that ZEB1 inhibition was driven by miR-101-3p, miR-139-5p, miR-144-3p, miR-199b-5p, and miR-200c-3p and that the FaDu Cell Line inhibition occurred at the mRNA level, whereas HN13 did not affect mRNA expression but decreased protein levels. Furthermore, we demonstrated the ability of the ZEB1 inhibitor miRNAs to modulate CSC-related genes, such as TrkB, ALDH, NANOG, and HIF1A, using transfection technology. We showed that ALDH was upregulated upon ZEB1-suppressed miRNA transfection (Mann-Whitney ** p101 = 0.009, t-test ** p139 = 0.009, t-test ** p144 = 0.002, and t-test *** p199 = 0.0006). Overall, our study enabled an improved understanding of the role of ZEB1-suppressed miRNAs in CSC biology.

DNMT3B C46359T and SHMT1 C1420T polymorphisms in the folate pathway in carcinogenesis of head and neck.

Folate is an essential nutrient with important roles in the synthesis, repair, and DNA methylation. Polymorphisms in genes encoding enzymes involved in folate metabolism can change these processes and modulate cancer development. We investigated DNMT3B C46359T (rs2424913) and SHMT1 C1420T (rs1979277) polymorphisms related to folate pathway in head and neck cancer (HNC) risk and the association of the disease with gender, risk factors and clinical histopathological parameters. A case-control study was conducted in 725 individuals (237 patients with HNC and 488 control individuals). Real-time PCR technique was performed for genotyping. Chi square and multiple logistic regression tests were used for statistical analysis. Male gender (OR 1.80; 95 % CI 1.11-2.94; P < 0.02) and tobacco consumption (OR 6.14; 95 % CI 4.13-9.13; P < 0.001) were associated with increased risk for this neoplasia. There were no significant associations between the polymorphisms and risk of disease, however, the tobacco and alcohol habits together showed association with SHMT1 C1420T polymorphism (OR 1.48; 95 % CI 1.08-2.03; P = 0.014). SHMT1 C1420T polymorphism was associated with larynx tumor (OR 0.48; 95 % CI 0.27-0.86; P < 0.05). In conclusion, tobacco habit and male gender can be predictors for HNC risk. SHMT1 C1420T and DNMT3B C46359T polymorphisms are not associated with HNC development in Brazilian population, however, SHMT1 C1420T polymorphism is less frequent in patients with primary site of tumor in larynx and more frequent in individuals who consume tobacco and alcohol together. Further studies involving gene-gene interactions in folate pathway in different populations can contribute to the understanding of the polymorphisms effect on HNC risk.

Association between GSTP1, GSTM1 and GSTT1 polymorphisms involved in xenobiotic metabolism and head and neck cancer development.

Polymorphisms in the glutathione S-transferase superfamily genes that encodes enzymes involved in the phase II xenobiotic metabolism may lead head and neck cancer development. In this study we investigate the association of A313G and C341T GSTP1 polymorphisms, GSTM1 and GSTT1 null genotypes in the head and neck cancer development, interactions between these polymorphisms,the tumor histopathologic parameters and risk factors (smoking and drinking) were also evaluated in the case-control study. 775 individuals (261 patients/514 controls) were included in the study. Molecular analyzes were performed by PCR and PCR-RFLP; and statistical analyzes by Chi square and multiple logistic regression. Chi square test showed that only the genotype frequencies for GSTM1 and GSTT1 were in Hardy-Weinberg disequilibrium in both groups. Significant results with p ≤ 0.05 showed that age ≥ 48 years (OR = 11.87; 7.55-18.65), smoking (OR = 4.25; 2.70-6.69), drinking (OR = 1.59; 1.02-2.46) were possible predictors for the head and neck cancer development and the presence of A313G GSTP1 polymorphism (OR = 0.62; 0.42-0.92) decreased the risk for this disease. Individuals with the 313AG/GG GSTP1 and age ≥ 48 years (OR = 0.59; 0.38-0.91), male gender (OR = 0.54; 0.35-0.83), smokers (OR = 0.63; 0.40-0.99) and drinkers (OR = 0.57; 0.35-0.95); the GSTM1 null genotype and age < 48 years (OR = 2.46; 1.09-5.55); the GSTT1 null genotype and primary anatomical sites of pharynx (OR = 0.37; 0.17-0.79) and larynx (OR = 3.60; 1.93-6.72), can modulate the risk for the disease development. The variables age ≥ 48 years, smoking and drinking can be predictors for head and neck cancer development; moreover, A313G GSTP1 polymorphism, GSTM1 and GSTT1 null genotypes can modulate the risk for this disease.

Relationship of obstructive sleep apnea syndrome with the 5-HT2A receptor gene in Brazilian patients.

BACKGROUND: Serotonin (5-HT) regulates a variety of visceral and physiological functions, including sleep. Polymorphisms in the 5-HT2A receptor gene can alter its transcription, affecting the number of receptors in the serotoninergic system, contributing to obstructive sleep apnea syndrome (OSAS). OBJECTIVE: The aim of this study was to determine the prevalence of the 102T-C and -1438G-A polymorphisms in the 5-HTR2A gene in Brazilian patients with and without OSAS. SUBJECTS AND METHODS: A cross-sectional study performed at the Otorhinolaryngology and Sleep Disorder Out Clinics, São José do Rio Preto Medical School, FAMERP. One hundred patients were examined as index cases and 100 persons as controls, of both genders to both groups. DNA was extracted from peripheral blood leukocytes, and the sites that encompassed both polymorphisms were amplified by PCR-RFLP. RESULTS: There was a significant prevalence of the male gender in index cases compared with the control group gender (p < 0.0001). There was no significant genotypic difference in the 102T-C polymorphism between the case and control groups (p = 1.000). The AA genotype of the -1438G-A polymorphism was more prevalent in the patients with OSAS compared with the controls (OR, 2.3; CI 95% 1.20-4.38; p = 0.01). CONCLUSIONS: There was no difference in the prevalence of the 102T-C polymorphism between patients with OSAS and the control group. Serotoninergic system dysfunction appeared to be related to OSAS. The -1438G-A polymorphism and OSAS are related in this studied Brazilian population.

Molecular pathogenesis of juvenile nasopharyngeal angiofibroma in brazilian patients.

Juvenile nasopharyngeal angiofibroma (JNA) is a vascular tumor of the nasopharynx that accounts for 0.5% of all cancers of the head and neck. It primarily affects males aged 14-25 years. Of the many genes that mediate the development of JNA, GSTM1 has been most frequently associated with this vascular tumor. The loss of expression of GSTM1 (null genotype) is linked to the development of these tumors. The aim of this cross-sectional case study was to examine the prevalence of the GSTM1-null genotype in Brazilian patients with JNA. DNA was extracted from the leukocytes of blood samples from 10 patients. GSTM1 genotypes were analyzed using a PCR-based assay that was designed to identify the wild-type allele of GSTM1. All 10 patients (100%) were males, with a mean age of 17.8 years. The null genotype for GSTM1 was noted in 4 patients (40%)-1 (10%) at Fisch stage I, 1 (10%) at stage III, and 2 (20%) at stage II. No patient with this genotype had stage IV disease. There was no correlation between Fisch classification and GSTM1 genotype (P = .5695). The correlation between age at diagnosis and GSTM1 genotype was not significant (P = .728). The present findings indicate that there is evidence of an association between the GSTM1-null genotype and JNA in this studied Brazilian population.

Q36R polymorphism of KiSS-1 gene in Brazilian head and neck cancer patients.

The KiSS-1 metastasis-suppressor gene (KiSS-1) product (metastin, kisspeptin) is reported to act after binding with the natural ligand of a G-protein coupled receptor and this gene product inhibits chemotaxis, invasion, and metastasis of cells. The aim of this study was to evaluate the Q36R polymorphism of KiSS-1 in patients with head and neck cancer and to compare the results with healthy individuals and its association with clinicopathological parameters. Gender, age, smoking and alcohol consumption were analyzed for 744 individual (252 head and neck cancer patients and in 522 control individuals). The molecular analysis of these individuals was made after extraction of genomic DNA using the SSCP-PCR technique. This study did not reveal any significant differences in genotype frequencies between healthy individuals and patients with head and neck cancer or with the clinical parameters. This study showed an increase frequency of the Q36R polymorphism in pharyngeal cancer.

Polymorphisms and haplotypes in methylenetetrahydrofolate reductase gene and head and neck squamous cell carcinoma risk.

Functional polymorphisms in genes encoding enzymes involved in folate metabolism might modulate head and neck carcinoma risk because folate participates in DNA methylation and synthesis. We therefore conducted a case-control study of 853 individuals (322 head and neck cancer cases and 531 non-cancer controls) to investigate associations among MTHFR C677T and MTHFR A1298C polymorphisms and head and neck squamous cell carcinoma risk. Interactions between these two polymorphisms and risk factors and clinical histopathological parameters were also evaluated. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used to genotype the polymorphisms and Chi-square test and multiple logistic regression were used for statistical analyses. The variables age≥49 years, male gender, tobacco habits and alcohol consumption, MTHFR 1298 AC or CC genotypes, combined genotypes with two or more polymorphic alleles and 677T and 1298C polymorphic alleles were associated with increased risk for this disease (P<0.05). Furthermore, we found that 1298 AC or CC genotypes were associated with age≥49 years, tobacco and alcohol habits (P<0.05). Regarding clinical histopathological parameters, the A1298C polymorphism was more frequent in patients with oral cavity as primary site (P<0.05). MTHFR polymorphisms may contribute for increase risk for head and neck carcinoma and the variables age≥49 years, male gender, tobacco and alcohol habits were associated with MTHFR 1298AC or CC genotypes, confirming that individuals with these variables and MTHFR A1298C polymorphism has higher risk for this disease.

Polymorphisms of the CYP1A1 and CYP2E1 genes in head and neck squamous cell carcinoma risk.

Polymorphisms in genes that encode P450 cytochrome enzymes may increase carcinogen activation or decrease their inactivation and consequently, promote the development of cancer. The aims of this study were to identify the MspI-CYP1A1, PstI-CYP2E1 and DraI-CYP2E1 polymorphisms in patients with head and neck cancer and to compare with individuals without cancer; to evaluate the association of these polymorphisms with risk factors and clinical histopathological parameters. In the study group, 313 patients were evaluated for CYP1A1, 217 for CYP2E1 (PstI) and 211 for CYP2E1 (DraI) and in the control group 417, 334 and 374 individuals, respectively. Molecular analysis was performed by PCR-RFLP technique, and chi-square and multiple logistic regression tests were used for statistical analysis. The result of analysis regarding individuals evaluated for CYP1A1 (MspI) showed that age (OR: 8.15; 95% CI 5.57-11.92) and smoking (OR: 5.37; 95% CI 3.52-8.21) were predictors for the disease; for the CYP2E1 (PstI and DraI), there were associations with age (PstI-OR: 9.10; 95% CI 5.86-14.14/DraI-OR: 8.07; 95% CI 5.12-12.72), smoking (PstI-OR: 4.10; 95% CI 2.44-6.89/DraI-OR: 5.73; 95% CI 3.34-9.82), alcohol (PstI-OR: 1.93; 95% CI 1.18-3.16/DraI-OR: 1.69; 95% CI 1.02-2.81), respectively, with disease development. CYP2E1 (PstI) was less frequent in patient group (OR: 0.48; 95% CI 0.23-0.98). Regarding clinical histopathological parameters, CYP1A1 polymorphism was less frequent in the larynx primary anatomic site (OR = 0.45; 95% CI = 0.28-0.73; P = 0.014). In conclusion, we confirm that age, smoking and alcohol consumption are risk factors for this disease and the polymorphisms investigated have no association with the development of head and neck cancer.

MTHFD1 G1958A, BHMT G742A, TC2 C776G and TC2 A67G polymorphisms and head and neck squamous cell carcinoma risk.

Alterations in folate metabolism may contribute to the process of carcinogenesis by influencing DNA methylation and genomic stability. Polymorphisms in genes encoding enzymes involved in this pathway may alter enzyme activity and consequently interfere in concentrations of homocysteine and S-adenosylmethionine that are important for DNA synthesis and cellular methylation reactions. The objectives were to investigate MTHFD1 G1958A, BHMT G742A, TC2 C776G and TC2 A67G polymorphisms involved in folate metabolism on head and neck cancer risk and the association between these polymorphisms with risk factors. Polymorphisms were investigated in 762 individuals (272 patients and 490 controls) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and Real Time-PCR. Chi-square and Multiple logistic regression were used for the statistical analysis. Multiple logistic regression showed that tobacco and male gender were predictors for the disease (P < 0.05). Hardy-Weinberg equilibrium showed that the genotypic distributions were in equilibrium for both groups in all polymorphisms studied. The BHMT 742GA or AA genotypes associated with tobacco consumption (P = 0.016) increase the risk for head and neck squamous cell carcinoma (HNSCC). The present study suggests that BHMT 742GA polymorphism associated to tobacco modulate HNSCC risk. However, further investigation of gene-gene interactions in folate metabolism and studies in different populations are needed to investigate polymorphisms and HNSCC risk.

Occupational stress and work engagement among primary healthcare physicians: a cross-sectional study.

BACKGROUND: Brazil's Family Health Strategy is based on a primary healthcare model, which is considered to have case resolution capacity, with physicians at its center. OBJECTIVES: To evaluate the levels of occupational stress and work engagement among primary healthcare physicians. DESIGN AND SETTING: Cross-sectional study conducted in 2017, in São José do Rio Preto, São Paulo, Brazil. METHODS: A non-probability sample including 32 physicians from family health teams was used. Three self-applied instruments were used: a scale developed by the researchers seeking sociodemographic and professional variables, the Work Stress Scale and the Utrecht Work Engagement Scale. RESULTS: Female professionals (59.4%), permanent employees (56.3%), workload of 40 hours per week (59.4%) and 3-10 years of acting in primary care (68.8%) were more prevalent. Six professionals (19.4%) exhibited significant stress (score ≥ 2.5). The main stressors were lack of prospects for career growth (2.9 ± 1.3), form of task distribution (2.7 ± 1.0), poor training (2.7 ± 1.2) and insufficient time to perform the job (2.6 ± 1.2). Levels of work engagement ranged from 4.3 to 4.6 and were rated as high in all dimensions. Physicians with occupational stress had average levels of work engagement, whereas those without occupational stress had high levels of work commitment. CONCLUSIONS: A notable percentage of the physicians were experiencing occupational stress. The physicians had high levels of work engagement. Occupational stress was negatively correlated with work engagement, and it significantly compromised physicians' levels of work engagement and interfered with their positive relationship with the work environment.

Treatment effects of the EGFR pathway drugs on head and neck cancer stem cells.

(1) Head and neck cancer (HNC) is the sixth most common cancer worldwide and show low survival rates and drug resistance, which can be due to the presence of cancer stem cells (CSCs), a small cell population with metastatic potential, invasion and self-renewal ability. (2) Here, seven tumor cells were sorted as CD44+/CD117+/CD133+ or ALDH+, considered as HNC stem cells (HNCSCs), and as CD44-/CD117-/CD133- or ALDH-, considered non-HNCSCs after both cells sorted criteria was compared to evaluate cell migration, invasion, and colony forming assays. These subpopulations were treated with Cetuximab, Paclitaxel, or a combination of both drugs and evaluated for cell viability. Quantitative PCR and western blot were performed to evaluate EGFR, TRKB, KRAS and HIF-1α gene and protein expression. (3) HNCSCs presented more colonies and appeared to be more sensitive to the drug combination when compared with non-HNCSCs, regardless cells sorted criteria and primary tumor subsite. The EGFR, TRKB, KRAS and HIF-1α genes and proteins were upregulated in CSCs compared with non-HNCSCs, thus explaining the drug resistance. (4) This study contributes to the better development of specific therapeutic protocols based on Cetuximab and Paclitaxel drugs in the treatment of HNC in the presence of CSCs and cell proliferation biomarkers.

A80G polymorphism of reduced folate carrier 1 (RFC1) gene and head and neck squamous cell carcinoma etiology in Brazilian population.

Reduced folate carrier is an essential folate transporter and the A80G polymorphism in reduced folate carrier 1 gene (rs1051266) has been shown to be associated with alterations in folate metabolism and consequently cancer development. We evaluated the association of this polymorphism with head and neck squamous cell carcinoma risk in a case-control study of 322 head and neck carcinoma patients and 531 individuals without cancer in a Brazilian population and association of this polymorphism with clinical histopathological parameters, and gender and lifestyle factors. The PCR-RFLP technique was used to genotype the polymorphism and multiple logistic regression was used for comparison between the groups and for interaction between the polymorphism and risk factors and clinical histopathological parameters. We observed association between the RFC1 A80G polymorphism and the risk of this disease. Male gender, tobacco habit and RFC1 AG or GG genotypes may be predictors of this disease (P < 0.05). The genotype, 80AG or GG was associated with for >50 years, male gender and non alcohol consumption (P ≤ 0.05). The polymorphism did not show any association with the primary site, aggressiveness, lymph node involvement or extension of the tumor. In conclusion tobacco and male gender are associated with etiology of this disease and our data provide evidence that supports an association between the RFC1 A80G polymorphism and head and neck squamous cell carcinoma risk, male gender, alcohol non consumption and age over 50 years. However, further studies of folate and plasma concentrations may contribute to the better understanding of the factors involved in the head and neck squamous cell carcinoma etiology.

Anti-EGFR treatment effects on laryngeal cancer stem cells.

Laryngeal cancer (LC) is one of the common head and neck neoplasms and is characterized by resistance to conventional therapy and poor prognosis. This may result from the presence of cancer stem cells (CSCs), which form a small population in tumors with metastatic potential, high invasive capacity, self-renewal, and differentiation. This study aimed to evaluate the effectiveness of 5-fluorouracil and cisplatin individually, as well as the combination of cetuximab and paclitaxel in a CSC subpopulation separated with biomarkers related to tumoral growth (CD44, CD117, and CD133). In addition, expression of TrkB, KRAS, HIF-1α, and VEGF-A genes and proteins related to cell proliferation were evaluated in this subpopulation. The CD44, CD133, and CD117 biomarkers were used to analyze the identification and separation of both subpopulations using FACSAria Fusion. Subpopulations positive for CD44, CD133, and CD117 or lacking these biomarkers were classified as laryngeal cancer stem cells (LCSCs) or laryngeal cancer non-stem cells (non-LCSCs), respectively. Matrigel invasion and colony forming assays were performed to confirm CSC presence. Subpopulations were cultured and exposed to 5-fluorouracil, cisplatin, and cetuximab/paclitaxel drugs for 24 h. Cell proliferation was determined using MTS assay. KRAS and TrkB gene expression levels were evaluated using quantitative real time PCR with TaqMan® Assay in both subpopulations. The non-LCSC subpopulation was considered as the control for relative expression. We found that the LCSC subpopulation demonstrated more resistance to cetuximab and paclitaxel combination chemotherapy when compared with the non-LCSC subpopulation of the cell line. These LCSC subpopulations presented up-regulated expression of KRAS, HIF-1α, and VEGF-A genes and proteins and no TrkB gene expression, but TrkB protein expression was up-regulated in the LC cell line when compared to the non-CSC subpopulation. "In conclusion, the combination of CD44, CD133, and CD117 biomarkers has stem cell properties. Moreover, LCSCs, are capable of resisting treatment and present high KRAS, HIF-1α, and VEGF-A gene expression".

Gene Polymorphisms Involved in Folate Metabolism and DNA Methylation with the Risk of Head and Neck Cancer.

BACKGROUND: Folate is essential for DNA synthesis, repair, and methylation. Polymorphisms in genes associated with folate metabolism may alter these processes and, consequently, modulate cancer development. AIM: We aimed to assess DNMT3B -149C/T (rs2424913), DNMT3B -283T/C (rs6087990), DNMT3B -579G/T (rs2424909), DHFR 19-pb ins/del (rs70991108), SHMT1 1420C/T (rs1979277), and TYMS 28-bp tandem repeat (rs34743033) polymorphisms with risk of head and neck cancer. METHODS: A case-control study was conducted in 1,086 Brazilian individuals. Real-time and conventional polymerase chain reactions-PCR were performed for genotyping the polymorphisms. RESULTS: The single nucleotide polymorphism (SNP), DNMT3B -283T/C, revealed a higher risk of head and neck squamous cell carcinoma (HNSCC) when compared with the C group in the codominant (p < 0.001), dominant (p <0.001), and overdominant (p= 0.001) models for T/C and C/C genotypes. DNMT3B -149C/T and DNMT3B -579G/T revealed no association between groups in any model. The DHFR 19-pb ins/del polymorphism protected against HNSCC development compared to the C group by the codominant (p < 0.001), dominant (p < 0.001), and overdominant (p < 0.001) models. In the TYMS, the 3R/3R genotype had a protective effect against HNSCC development compared with the C group by the recessive models (p= 0.009). In contrast, SHMT1 1420 C/T presented no association between the HNSCC and C groups. DHFR 19-pb ins/del polymorphisms protected against oral cavity cancer (p= 0.003), and only TYMS-28 3R/3R decreased the risk of tumor progression (p= 0.023). In the Kaplan-Meier curve, an association was found between DHFR ins/ins and TYMS -28 3R carriers with respect to relapse-free time; further, DNMT3B -579 T and TYMS-28 2R/2R carriers had longer survival times. CONCLUSION: DNMT3B -283T/C is associated with higher risk, whereas DHFR 19-pb ins/del and TYMS 28 3R/3R protect against head and neck cancer. We also highlighted the association of TYMS 3R/3R genotype carriers with relapse-free cancer protection and survival time.

Glutathione S-transferase Polymorphisms in Head and Neck Squamous Cell Carcinoma Treated with Chemotherapy and/or Radiotherapy.

BACKGROUND/AIM: The Glutathione S-transferases (GSTs) are important carcinogen-metabolizing enzymes. Polymorphisms involved in these enzymes can modulate the development and treatment of head and neck cancer. To investigate the association of GSTs polymorphisms with head and neck cancer and risk factors, clinical-pathological features, and survival time of the patients treated with chemotherapy and/or radiotherapy. METHODS: The GST gene polymorphisms were evaluated in 197 cases and 514 controls by PCR-RFLP-Polymerase Chain Reaction Restriction Fragment Length Polymorphism. RESULTS: The GSTP-313 was associated with a decreased risk for HNSCC (p=0.050). The GSTP1 haplotype analysis revealed a higher frequency of the AC and AT haplotypes in the case group than in the control group (p=0.013 and p=0.019, respectively), and the opposite for G-C haplotype (p = 0.015). Yet, the different combinations between the genotypes were associated with an increased risk of cancer. The study showed no association between the polymorphisms and primary tumor site, clinical-pathological characteristics, treatment (chemotherapy and/or radiotherapy) and survival time of the patients. CONCLUSION: The GST polymorphisms combination showed an increased risk for carcinogenesis, and studies with larger casuistry can contribute to the clarification of the role in individual patient differences for the response to chemotherapy and/or radiotherapy and identify biomarkers of susceptibility.

Polymorphisms in MTHFR, MTR, RFC1 and CßS genes involved in folate metabolism and thyroid cancer: a case-control study.

INTRODUCTION: Polymorphisms in genes coding enzymes involved in folate metabolism may cause alterations in this metabolic pathway and contribute to carcinogenesis, because folate is essential for DNA synthesis, methylation and repair. The objective of this study was to investigate the association of MTHFR 677C>T (rs1801133), MTR 2756A>G (rs1805087), RFC1 80A>G (rs1051266) and CßS 844ins(68) (no rs#) polymorphisms and thyroid cancer development. The association of these polymorphisms with demographic risk factors and clinical histopathological parameters was also evaluated. MATERIAL AND METHODS: The study is a case-control analysis with a total of 462 individuals (151 patients and 311 controls). Polymerase chain reaction-restriction fragment length polymorphism technique was used for genotyping. The χ2 and multiple logistic regression were utilized for statistical analysis. RESULTS: The polymorphisms analysis revealed an association between the MTHFR 677C>T polymorphism (OR = 2.87, 95% CI: 1.50-5.48, p < 0.01, codominant model), (OR = 1.76, 95% CI: 1.18-2.64, p < 0.01, dominant model), (OR = 2.37, 95% CI: 1.28-4.39, p < 0.01, recessive model) and thyroid cancer. RFC1 80A>G polymorphism also was associated with thyroid cancer under recessive mode of inheritance (OR = 1.55; 95% CI: 1.02-2.38; p = 0.04); however, this polymorphism showed Hardy-Weinberg disequilibrium in the control group (χ2 = 24.71, p < 0.001). Furthermore, alcohol (OR = 1.56, 95% CI: 1.36-1.89, p < 0.01) and tobacco consumption (OR = 1.97, 95% CI: 1.28-3.04, p < 0.01) were associated with increased risk for thyroid cancer. The MTR 2756A>G polymorphism showed an association with tumor extent (OR = 2.69, 95% CI: 1.27-5.71, p < 0.01) and aggressiveness (OR = 4.51, 95% CI: 1.67-12.1, p < 0.01). CONCLUSIONS: MTHFR 677C>T is significantly associated with increased risk for thyroid cancer and MTR 2756A>G is associated with tumor extent and aggressiveness. In addition, alcohol and tobacco consumption were associated with increased risk of thyroid cancer. These results may contribute to a better prognosis for thyroid cancer.

Screening of the mitochondrial A1555G mutation in patients with sensorineural hearing loss.

UNLABELLED: The A1555G mitochondrial mutation is the main alteration associated with aminoglycoside-induced deafness. AIM: to investigate the prevalence of the A1555G mutation in patients sensorineural hearing loss patients with and without aminoglycosides antibiotic use. MATERIAL AND METHOD: a study of 27 cases with deafness as the sample, and 100 neonates with normal hearing as the control group. DNA was extracted from blood leukocyte samples, and specific oligonucleotide primers were designed to amplify the cytochrome b gene and the region which encloses the A1555G mutation of the mitocondrial DNA using the polymerase chain reaction and restriction fragment length polymorphism. DESIGN: a cross-sectional case study. RESULTS: a region of the cytochrome b gene was amplified and the presence of the mtDNA was confirmed in all of the 127 cases. The A1555G mutation was not found in any of the 27 patients with hearing loss or the control group with 100 neonates. CONCLUSION: the results agree with studies stating that the A1555G mutation is not prevalent in the Americas. There is interest in establishing the real prevalence of this mutation and to investigate other mutations that may cause hearing loss, associated or not with the use of aminoglycosides, in the Brazilian population.

Epidemiologic evaluation of head and neck patients in a university hospital of Northwestern São Paulo State.

UNLABELLED: Head and neck cancer accounts for nearly 200.000 new cases worldwide. A mean of 13.470 new cases of cancer in the oral cavity for 100.000 inhabitants is observed in Brazil. AIM: To analyze clinical and epidemiological aspects in patients consulted in the Otorhinolaryngology and Head and Neck Surgery ward in a University hospital of Northwestern São Paulo, Brazil. MATERIALS AND METHODS: A total of 427 patients consulted in the hospital in the period from 2000 to 2005 were investigated. The variables analyzed included: age, gender, occupation, skin color, tobacco and alcohol consumption, primary site of the tumor, clinical staging, degree of histological differentiation and outcome. The data was analyzed by descriptive and exploratory statistics. RESULTS: Prevalence was found among men (86%), white color (90%), smokers (83.37%), and alcoholics (65.80%); the average age was 61 years, 24.25% of men were farmers and 60% of women, housekeepers. Primary site of tumor was usually in the oral cavity (35.37%), with histological squamous cell. The incidence of deaths was 164. CONCLUSION: This study has provided the profile of the patients assisted in this hospital; moreover, it has contributed to outline further programs for preventing this disease.

Candidate Biomarkers for Oral Squamous Cell Carcinoma: Differential Expression of Oxidative Stress-Related Genes

Background: Alteration in the biotransformation of exogenous compounds can result in production of reactive oxygen species (ROS), which can predispose cells to malignant transformation in the head and neck. This study aimed to evaluate the expression of genes involved in antioxidant metabolism in the oral squamous cell carcinoma (OSCC). Methods: The expression of eighty-four genes was evaluated in OSCC and non-tumor tissues by quantitative real-time polymerase chain reaction using the TaqMan Gene Expression Array. The biological mechanisms related to the differentially expressed genes were investigated using Gene ­ NCBI, KEGG, UNIPROT and REACTOME databases. Results: Twenty-one genes encoding enzymes involved in antioxidant metabolism were differentially expressed in the OSCC case. Four genes (ATOX1, PRDX4, PRNP, and SOD2) were up-regulated, and seventeen (ALOX12, CAT, CSDE1, DHCR24, DUOX1, DUOX2, EPHX2, GLRX2, GPX3, GSR, GSTZ1, MGST3, PRDX1, OXR1, OXSR1, SOD1, and SOD3) were down-regulated. We identified 14 possible novel biomarkers for OSCC. The differentially expressed genes appeared related to important biological processes involved in carcinogenesis, such as inflammation, angiogenesis, apoptosis, genomic instability, invasion, survival, and cell proliferation. Conclusions: Our study identified novel biomarkers which might warrant further investigation regarding OSCC pathogenesis since the altered expression in the genes can modulate biological processes related to oxidative stress and predispose cells to malignant transformation in the oral cavity.

Rhinoseptoplasty in children.

INTRODUCTION: Untreated septal and/or nasal pyramid deviation in children should be corrected as soon as possible, because they can result in esthetic or functional problems years later. OBJECTIVE: To report the surgical experience in treating children with nasal septum and/or nasal pyramid deviation. METHODS: Review of medical records of 202 children, 124 (61.4%) males and 78 (38.6%) females, between 4 and 16 years of age (M=11 years) who underwent rhinoplasty and/or septoplasty in a Pediatric Otolaryngology Service of the Dept. of Otolaryngology and Head and Neck Surgery between January 1994 and January 2010. RESULTS: Septoplasty performed in 157 cases (77.7%); rhinoseptoplasty in 23 cases (11.4%), and rhinoplasty in 22 cases (10.9%). CONCLUSION: Nasal changes should be corrected in children, in order to provide harmonious growth, and prevent severe sequelae found in mouth breathers.