Comparative Evaluation of SMAD-2 Expression in Oral Submucous Fibrosis and Reactive Oral Lesions

Background: The event of fibrosis encompasses involvement of definite immunological and molecular mechanisms. As quite a lot of pro-fibrotic pathways are concerned, a multipronged approach is obligatory to cognize the fibrotic events. SMAD signaling pathway hasn’t been studied oral fibrotic events.In the progression of cramming the SMAD signaling pathway in OSMF, the first initiator protein of the pathway was considered for evaluation in the present study. Materials and Methods: A total of 100 subjects consisting of 20 controls, 40 patients with reactive lesions such as Traumatic Fibroma, Epulis Fissuratum and Gingival Hyperplasia and 40 patients with Oral Submucous Fibrosis were recruited for the study. Tissue homogenates were assayed by quantitative sandwich enzyme immunoassay technique using Human Mothers Against Decapentaplegic Homolog 2 (Smad2). Results: SMAD 2 expression values showed significant difference between control and OSMF group. However, the difference between reactive lesions with control and OSMF were not statistically significant. Conclusion: Graded increase of SMAD 2 expression from control,reactive lesions and OSMF were observed accentuating the role of SMAD signalling pathway in fibro genesis. Further this can be validated to generate effective antifibrotic targets.     

Pentoxifylline Therapy in the Management of Oral Submucous Fibrosis

Objectives: Oral submucous fibrosis is a common premalignant condition in the Indian subcontinent andis caused by chewing areca nut and other irritants in various forms. Its medical treatment is not yet fullystandardized. In this study we compared the efficacy of Pentoxifylline as compared to placebo. Materials andmethods: 75 patients suffering from oral submucous fibrosis were randomly divided into two groups A and B.Group A patients received placebo, while Group B patients received 400 mg. Pentoxifylline for a period of 7months. Treatment outcome was evaluated on the basis of improvement in symptom and sign scores. Student’s‘t’ test was applied for comparing the results. Results: The improvement in total (i.e. symptoms + sign) scorewas 25% in group A and 49.15% in group B. This difference was found to be statistically significant. (p < 0.05)Conclusion: Treatment regimen of group B was more effective. No significant side effects were seen. A follow upstudy is required to assess long term outcome of this therapy.     

Genetic Polymorphisms of CYP2E1 and GSTM1 in a Thai Population

Cytochrome P450 2E1 and GSTM1 play major roles in metabolic activation and detoxification of many carcinogensand polymorphisms in the encoding genes have been reported to be individually associated with increased susceptibilityto certain cancer. In the present study, we investigated the RsaI, PstI and DraI polymorphisms of the CYP2E1 geneand the null GSTM1 genotype in a Thai population. DNA samples from 485 individuals were analysed by polymerasechain reaction with restriction fragment length (PCR/RFLP). The frequency of RsaI and PstI predominanthomozygous alleles (c1/c1) was 73.2%, heterozygous allele (c1/c2) was 25.6% and rare homozygous allele (c2/c2)was 1.2%. For the DraI polymorphism, the frequency of the predominant allele (DD) was 59.6%, heterozygous (CD)was 40% and rare allele (CC) was 0.4%. The frequency of GSTM1 null genotype was 62.7%. The distribution andfrequencies of these alleles showed different pattern from those found in Caucasian and some other Asian populations.With the large population in this study, we believed that our results are reliable estimates of the frequencies of thepolymorphic CYP2E1 and GSTM1 alleles in Thai population and should provide a base for further epidemiologicalstudies on their links with cancer development.     

Tetra Primer ARMS PCR Optimization to Detect Single Nucleotide Polymorphisms of the CYP2E1 Gene

Single nucleotide polymorphism (SNP) detection has been used extensively for genetic association studies of diseases including cancer. For mass, yet accurate and more economic SNP detection we have optimized tetra primer amplification refractory mutation system polymerase chain reaction (ARMS PCR) to detect three SNPs in the cytochrome P450 2E1 (CYP2E1) gene locus; i.e. rs3813865, rs2070672 and rs3813867. The optimization system strategies used were (1) designing inner and outer primers; (2) determining of their optimum primer concentration ratios; and (3) determining of the optimum PCR annealing temperature. The tetra primer ARMS PCR result could be directly observed using agarose gel electrophoresis. The method succesfully determined three SNPs in CYP2E1 locus, the results being consistent with validation using DNA sequencing and restriction fragment length polymorphisms (RFLP).     

CYP2D6 and CYP2E1 Gene Polymorphisms and their Association with Cervical Cancer Susceptibility: A Hospital Based Case-Control Study from South-Western Maharashtra

Background: In last few years several studies all over the world discovered the genetic polymorphisms in different cytochrome P450 genes associated with risk of various cancers, but contradictory outcomes were evidenced in case of cervical cancer risk.  In this case-control study we aimed to see whether the polymorphism of CYP2D6 or CYP2E1 genes may or may not be associated with cervical cancer risk in women of rural Maharashtra. Methods: In this case-control study, the association of CYP2D6 and CYP2E1 gene polymorphism with cervical cancer risk was studied by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The study was conducted with 350 clinically confirmed cervical cancer patients and 350 healthy women in a population of South-Western Maharashtra. The Odds ratio (OR) with 95% confidence interval and p-value were evaluated, where p ≤0.005 was considered as statistically significant. Results: After the analysis of SNP (rs389209) of CYP2D6 and SNPs (rs2031920, rs6413432, rs6413420) of CYP2E1, we noticed that variant allele A of CYP2E1*6 showed significant increase in cervical cancer cases (OR=4.81; 95% CI: 1.57- 14.77; p=0.005). The genotypic distribution of heterozygote G/A genotype of CYP2D6*4 showed negative association with cervical cancer development when age of cancer occurrence (OR=0.41; 95% CI: 0.27- 0.61; p<0.0001) and tobacco history (OR=0.35; 95% CI: 0.20- 0.59; p=0.0001) was considered. Conclusion: The findings from this study supported that rs6413432 SNP of CYP2E1*6 increased cervical cancer risk in the studied rural women population.     

CYP1A1 Gene Polymorphisms: Modulator of Genetic Damage in Coal-Tar Workers

Aim: It is well known that polycyclic aromatic hydrocarbons (PAHs) such as benzo (a) pyrene have carcinogenicproperties and may cause many types of cancers in human populations. Genetic susceptibility might be due tovariation in genes encoding for carcinogen metabolizing enzymes, such as cytochrome P-450 (CYP450). Our studyaimed to investigate the effect of genetic polymorphisms of CYP1A1 (m1 and m2) on genetic damage in 115 coaltarworkers exposed to PAHs at their work place. Methods: Genetic polymorphisms of CYP1A1 were determinedby the PCR-RFLP method. Comet and buccal micronucleus assays were used to evaluate genetic damageamong 115 coal tar workers and 105 control subjects. Results: Both CYP1A1 m1 and CYP1A1 m2 heterozygousand homozygous (wt/mt+mt/mt) variants individually as well as synergistically showed significant association(P<0.05) with genetic damage as measured by tail moment (TM) and buccal micronuclei (BMN) frequencies incontrol and exposed subjects. Conclusion: In our study we found significant association of CYP1A1 m1 and m2heterozygous (wt/mt)+homozygous (mt/mt) variants with genetic damage suggesting that these polymorphismsmay modulate the effects of PAH exposure in occupational settings.     

Evaluation of Gustatory Function in Oral Submucous Fibrosis Patients and Gutka Chewers

Aim: The aim of the study is to assess and compare taste perception among Oral submucous fibrosis (OSMF)patients, Gutka chewers without OSMF and healthy subjects. Materials and methods: Ninety subjects (30 OSMF,30 Gutka chewers without OSMF and 30 controls) were enrolled in the study for assessing taste perception by filterpaper strips impregnated with different taste qualities. Taste perception assessment was also done in stage I, II and IIIOSMF subjects. The obtained data were analyzed using SPSS 20.0 software. Results: The gustatory defect was relatedto sweet, sour, bitter and salt, with significant changes in sour (33.3% showed hypoguesia) taste in OSMF subjects and13.3%showed hypoguesia to all tastants in gutka chewers and hypoguesia to salt, sour and bitter to grade III comparedin grade I and II. Conclusion: This study proved that there is significant alterations to taste perception with sour, salt,and bitter and then to sweet in OSMF subjects.     

Polymorphisms of CYP2D6 Gene and Gefitinib-Induced Hepatotoxicity

IntroductionGefitinib induces severe hepatotoxicity in approximately a quarter of Japanese patients with epidermal growth factor receptor (EGFR) mutation–positive non–small-cell lung cancer (NSCLC). Gefitinib is metabolized by cytochrome P450 (CYP) enzymes—including CYP3A4/5, CYP1A1, and CYP2D6—in the liver. We hypothesized that polymorphisms of the CYP2D6 gene may account for gefitinib-induced hepatotoxicity.Patients and MethodsPolymorphisms of the CYP2D6 gene were analyzed in 55 patients with NSCLC who experienced grade ≥ 2 transaminase elevation from gefitinib. The distribution of the CYP2D6 genotype was compared with that of the healthy Japanese population. The correlations between the nonfunctional allele *5 or the reduced-function allele *10 and hepatotoxicity-related clinical factors were also examined.ResultsThe distribution of the CYP2D6 genotype in the study participants was not different from that of the general Japanese population, reported previously. Existence of allele *5 or *10 did not correlate with clinical factors such as onset of hepatotoxicity within 2 months, grade ≥ 3 serum transaminase elevation, and tolerability to dose reduction or rechallenge of gefitinib. However, in 7 patients taking CYP3A4-inhibitory drugs, rechallenge of gefitinib again caused hepatotoxicity in 4 patients with allele *5 or *10 but not in 3 patients with normal alleles (P = .029). Moreover, switching to erlotinib did not cause hepatotoxicity in any of 17 patients with allele *5 or *10 but did in 3 of 8 patients without these alleles (P = .024).ConclusionReduced function of CYP2D6 may partly account for gefitinib-induced hepatotoxicity when CYP3A4 is inhibited. Erlotinib could be safely used in patients with decreased CYP2D6 activity even after they experienced gefitinib-induced hepatotoxicity.     

Estimation of Superoxide Dismutase and Glutathione Peroxidase in Oral Submucous Fibrosis,Oral Leukoplakia and Oral Cancer - A Comparative Study

Present study was undertaken to estimate and compare erythrocyte superoxide dismutase (E-SOD) andGlutathione peroxidase (GPx) levels in oral submucous fibrosis, oral leukoplakia and oral cancer patients andage/sex matched healthy subjects, 25 in each group. Statistically significant (P<0.001) decrease in E-SOD andGPx levels were observed in OSF, oral leukoplakia and oral cancer groups as compared to the control group.Oral leukoplakia group showed lower levels in comparison with OSF (P>0.05). Oral cancer group had the lowestlevels amongst the study groups. Imbalance in antioxidant enzyme status may be considered as one of the factorsresponsible for the pathogenesis of cancer and may serve as a potential biomarker and therapeutic target toreduce the malignant transformation in oral premalignant lesions/conditions.     

CYP2E1基因多态性与肺癌易感性关系的研究进展

肺癌是最常见的恶性肿瘤,其发生发展与吸烟、大气污染、危险因素暴露及基因变异等多种因素有关,由细胞色素P450(CYP450)基因家族所编码的细胞色素P450酶系(Cytochrome P450s)所组成的Ⅰ相酶介导氧化代谢,具有重要的解毒功能.CYP2E1是CYP450基因家族重要成员之一,大量研究表明其基因多态性与肺癌易感性密切相关,但研究结果不一致.     

The Relationship between Aryl Hydrocarbon Hydroxylase and Polymorphisms of the CYP1A1 Gene

We examined the relationship between aryl hydrocarbon hydroxylase (AHH) and the frequency of a Msp I mutation in the 3'-flanking region of cytochrome P450 (CYP) 1A1 (Mspl polymorphism) and another mutation in exon 7 (Ile-Val polymorphism) in 84 healthy male subjects in Fukuoka, Japan. AHH inducibility (3-methylcholanthrene (MC)-induced AHH activity/non-induced AHH activity) was correlated with the MspI polymorphism (P<0.0001) and age class (P=0.015), whereas no correlation was found for the Ile-Val polymorphism (P=0.509). Age-adjusted AHH inducibility (mean±SE) of the predominant homozygote (genotype A), the heterozygote (genotype B) and a homozygote rare allele (genotype C) genotypes was 4.89±0.36, 4.82±0.29 and 13.61±1.44, respectively. The genotype C showed much higher AHH inducibility than genotypes A and B (P<0.001), while no significant difference was observed between genotypes A and B. Non-induced AHH activity was also correlated with these polymorphisms. The AHH activity of a homozygous mutant Val/Val genotype (0.076±0.010 pmol/min/10⁶ cells) was significantly higher (P<0.05) than that of the wild-type homozygous Ile/Ile (0.044±0.004 pmol/min/10⁶ cells) and heterozygous Ile/Val (0.047±0.007 pmol/min/10⁶ cells) genotypes. Our study suggests that the genotypes C and Val/Val, which are more frequent in smoking-related lung cancer, are closely related with high AHH inducibility and high non-induced AHH activity, respectively. Thus, the positive relationship between AHH inducibility and lung cancer is supported by our study. If our results are confirmed and the assessment of genotype becomes feasible on a population basis, identification of smokers who have genetically high susceptibility to lung cancer (genotype C or Val/Val) may become important for the prevention of lung cancer.     

A Digital Cephalometric Study on The Morphometric Evaluation of Soft Palate in Oral Submucous Fibrosis

Objective: Oral submucous fibrosis (OSMF) is a chronic precancerous condition affecting the oral cavity, which is progressive and characterised by burning sensation and fibrotic change leading to restriction of mouth opening. This study evaluated the morphology of soft palate in different stages of OSMF patients using digital lateral cephalogram and compare it with healthy individuals. Methods: The study included 60 subjects, who were grouped as 30 OSMF and 30 healthy subjects from the same geographic population. Digital lateral cephalograms were taken with Planmeca Proline XC (Oy, Helsinki, Finland). Soft palate morphology was evaluated using Lateral Cephalogram, and the results were analysed statistically. Results: Leaf-shaped (Type 1) soft palate was commonly seen in the control group and stage I and II OSMF. Stage III OSMF patients presented with a butt-shaped (Type 3) soft palate. As the disease progressed, there was a conversion of Type 1 variety of soft palate to Type 3 variety. There was a gradual reduction in the length of the soft palate in the anteroposterior direction in OSMF patients compared to the control group. Conclusion: Early cephalometric diagnosis of soft palate changes may play a pivotal role in the overall management of OSMF.     

CYP2E1*5B,CYP2E1*6, CYP2E1*7B,CYP2E1*2, and CYP2E1*3 Allele Frequencies in Iranian Populations

Background: CYP2E1 encodes an enzyme which is mainly involved in bioactivation of potential carcinogenssuch as N-nitrosamines. Polymorphisms in the gene have been reported to be associated with cancer. The aim ofthis study was to evaluate genotype distributions and allele frequencies of five CYP2E1 polymorphisms in IranMaterials and Methods: Two hundred healthy individuals of an Iranian population from the southwest wereincluded in this study. PCR-restriction fragment length polymorphism and Tetra-ARMS PCR methods wereapplied for CYP2E1 genotyping. Results: The allele frequencies for *5B, *6, *7B, *2, and *3 were calculated tobe 1.5%, 16%, 28.5%, 0%, and 2.75% respectively. Results of this study showed that no significant differencesin genotype and allele frequencies of five single nucleotide polymorphisms with respect to the gender andtribes. The chi-square test showed that the genotype frequencies of CYP2E1*5B were similar to Caucasians,but the distribution of CYP2E1*6 genotypes was similar to Asians. The frequencies of CYP2E1*2 (0%) andCYP2E1*3 (2.75%) alleles were within the range for Caucasians and Orientals. In the case of CYP2E1*7B, thedata werelimited. Accordingly, the results were only compared with Europeans and the comparison showedsignificant differences. Conclusions: In conclusion, ethnic and geographic differences may explain discrepanciesin the prevalence of CYP2E1 polymorphisms.     

Mutation Analysis of the Dimer Forming Domain of the Caspase 8 Gene in Oral Submucous Fibrosis and Squamous Cell Carcinomas

Background: Missense and frame-shift mutations within the dimer forming domain of the caspase 8 genehave been identified in several cancers. However, the genetic status of this region in precancerous lesions, likeoral submucous fibrosis (OSMF), and well differentiated oral squamous cell carcinomas (OSCCs) in patientsfrom southern region of India is not known, and hence the present study was designed to address this issue.Materials and Methods: Genomic DNA isolated from biopsy tissues of thirty one oral submucous fibrosis andtwenty five OSCC samples were subjected to PCR amplification with intronic primers flanking exon 7 of thecaspase 8 gene. The PCR amplicons were subsequently subjected to direct sequencing to elucidate the status ofmutation. Results: Sequence analysis identified a frame-shift and a novel missense mutation in two out of twentyfive OSCC samples. The frame-shift mutation was due to a two base pair deletion (c.1225_1226delTG), whilethe missense mutation was due to substitution of wild type cysteine residue with phenylalanine at codon 426(C426F). The missense mutation, however, was found to be heterozygous as the wild type C426C codon was alsopresent. None of the OSMF samples carried mutations.Conclusions: The identification of mutations in OSCClesions but not OSMF suggests that dimer forming domain mutations in caspase 8 may be limited to malignantlesions. The absence of mutations in OSMF also suggests that the samples analyzed in the present study maynot have acquired transforming potential. To the best of our knowledge this is the first study to have exploredand identified frame-shift and novel missense mutations in OSCC tissue samples.     

Morphometric Analysis in Potentially Malignant Head and Neck Lesions: Oral Submucous Fibrosis

Objective: The objective of this study is to analyze cases of oral submucous fibrosis (OSMF) Grade I, II, IIIand IV morphometrically with regard to epithelium, vasculature and fibrosis and determine any correlationwith histological grading after Pindborg and Sirsat. Materials and methods: Eighty three oral submucous fibrosiscases were analyzed morpometrically using an interactive image analysis system in the Department of Pathology,M.L.N Medical College, Allahabad, U.P, India. Paraffin embedded sections of 3-4 μm thickness were stainedwith hematoxylin/eosin, Van Gieson’s picric acid and acid fuchsin stain and Masson’s trichrome stains. Imageanalysis was performed with specific software (Image –Pro Plus 6.0) and data obtained were finally transportedto Excel sheets for calculation of average values for each parameter. Results:With the grading criteria applied,9 cases of OSMF were grade I, 32 grade II, 39 grade III and 3 grade IV. Clinical trismus was most frequent inGrade IV followed by Grade III, II and I respectively. OSMF Grade I cases did not show any measurableamount of collagenization, whereas it showed a significant increase with OSMF I and II grades [Pearson’s χ2test= 85.72; p= 0.051] and OSMF-III and IV [Pearson’s χ2test=188.74; p< 0.001]. Numbers of endothelial cellsper low power field consistently decreased with the increasing grade. Conclusions: We concluded that meanblood vessel area and the mean vessel diameter showed a marked increase in grade II and a marker decrease ingrade IV and the grade III, collagen thickness (μm) increases according to increasing grade while density ofendothelial cells decreases .     

Lymphocyte subpopulations B,T and null—In Oral Submucous Fibrosis

The circulating T, B and null cell populations were quantified in Oral Submucous Fibrosis (O.S. M.F.), a disease found almost exclusively in Indians. The absolute null count was significantly increased (Sem=8.0122, n=32) while the absolute T lymphocytes were significantly decreased (Sem=3.6250, n=32). The B-cell populations were within normal limits.     

Four Polymorphisms in the Cytochrome P450 1A2 (CYP1A2) Gene and Lung Cancer Risk: a Meta-analysis

Background: Previous published data on the association between CYP1A2 rs762551, rs2069514, rs2069526,and rs2470890 polymorphisms and lung cancer risk have not allowed a definite conclusion. The present metaanalysisof the literature was performed to derive a more precise estimation of the relationship. Materials andMethods: 8 publications covering 23 studies were selected for this meta-analysis, including 1,665 cases and 2,383controls for CYP1A2 rs762551 (from 8 studies), 1,456 cases and 1,792 controls for CYP1A2 rs2069514 (from 7studies), 657 cases and 984 controls for CYP1A2 rs2069526 (from 5 studies) and 691 cases and 968 controls forCYP1A2 rs2470890 (from 3 studies). Results: When all the eligible studies were pooled into the meta-analysisfor the CYP1A2 rs762551 polymorphism, significantly increased lung cancer risk was observed in the dominantmodel (OR=1.21, 95 % CI=1.00-1.46). In the subgroup analysis by ethnicity, significantly increased risk of lungcancer was observed in Caucasians (dominant model: OR=1.29, 95%CI=1.11-1.51; recessive model: OR=1.33,95%CI=1.01-1.75; additive model: OR=1.49, 95%CI=1.12-1.98). There was no evidence of significant associationbetween lung cancer risk and CYP1A2 rs2069514, s2470890, and rs2069526 polymorphisms. Conclusions: Insummary, this meta-analysis indicates that the CYP1A2 rs762551 polymorphism is linked to an increased lungcancer risk in Caucasians. Moreover, our work also points out the importance of new studies for rs2069514associations in lung cancer, where at least some of the covariates responsible for heterogeneity could be controlled,to obtain a more conclusive understanding about the function of the rs2069514 polymorphism in lung cancerdevelopment.     

Breast Cancer Association with CYP1A2 Activity and Gene Polymorphisms - a Preliminary Case-control Study in Tunisia

The aim of the present study was to evaluate the relative contribution of CYP1A2 isoforms (-3860 G/A,-2467T/delT and -163C/A) in control subjects and breast cancer patients to the metabolism of caffeine in humanliver. Restriction fragment length polymorphism analysis of PCR-amplified Fragments (PCR-RFLP) was usedfor the genotyping of CYP1A2 SNPs and HPLC allowed the phenotyping through the measurement of CYP1A2activity using the 17X + 13X + 37X/137X urinary metabolite ratio (CMR) and plasma caffeine half life (T1/2).The CYP1A2 -3860A genotype was associated with a decreased risk of breast cancer. In contrast, distributionsof the CYP1A2 -2467T/delT or -2467delT/delT and -163A/C or A/A genotypes among breast cancer patients andcontrols were similar. When the genotype and phenotype relationship was measured by comparing the meanCMR ratios and caffeine half life within the genotype groups between subjects and breast cancer patients, therewere no significant differences except for -3860 A, most of them being homozygous for the -3860 G/G SNP andhad a significant higher mean CMR ratio and half life than those with -3860 G/A (P=0.02). The results of thispreliminary study show a significant association between CP1A2 -3860 G variant and CYP1A2 phenotype whichmust be confirmed by further large-size case-control studies.