Rama Devi Mittal

Impact of Toll-like receptors [TLR] 2 (−196 to −174 del) and TLR 4 (Asp299Gly, Thr399Ile) in cervical cancer susceptibility in North Indian women

OBJECTIVE(S) Targeting the Toll-like receptor (TLR) signaling pathway in elucidating the cellular and molecular mechanisms of human diseases, including cervical cancer, is gaining tremendous importance. The aim of our study was to identify the role of TLR 2(-196 to -174 del) and TLR 4(Asp299Gly and Thr399Ile) gene polymorphisms in cervical cancer susceptibility in North Indian women. METHODS For the study, blood samples were collected from histopathologically confirmed patients of cervical cancer (n=150) and unrelated, healthy female controls of similar ethnicity (n=150). Genomic DNA was extracted from peripheral blood leukocytes using salting-out method. TLR 2 and TLR 4 genotyping was done using Polymerase Chain Reaction and Restriction Fragment Length Polymorphism followed by 10% polyacrylamide gel electrophoresis. RESULTS TLR 2 del allele showed significant association (p=0.048, OR=1.6 [95%CI=1.00-2.51]) with cervical cancer susceptibility, while no significant association was found with TLR 4 (Asp299Gly and Thr399Ile). However, TLR 4 Thr/Ile genotype was found to be significantly associated with early stage (Stage II) of cervical cancer (p=0.044, OR=2.51 [95%CI=1.03-6.12]). Furthermore, TLR 2 ins/del genotype showed strong association (p=0.015, OR=1.95 [95%CI=1.14-3.33]) with tobacco usage in women with cervical cancer. CONCLUSION(S) Our study highlighted the involvement of TLR 2 (-196 to -174 del) and TLR 4 (Thr399Ile) gene polymorphisms in cervical cancer susceptibility. The TLR gene polymorphisms, upon further evaluation, may be helpful in elucidation of immunobiological mechanisms associated with cervical cancer susceptibility.

Genetic polymorphism of glutathione S‐transferase genes (GSTM1, GSTT1 and GSTP1) and susceptibility to prostate cancer in Northern India

To examine the association of glutathione‐S‐transferase (GST) gene polymorphisms in patients with sporadic prostate cancer, in a North Indian population, as GSTs are active in detoxifying a wide variety of endogenous or exogenous carcinogens, and genetic polymorphisms of GSTM1, GSTT1 and GSTP1 have been assessed to evaluate the relative risk of various cancers.

Investigative Role of Pre-MicroRNAs in Bladder Cancer Patients: A Case–Control Study in North India

MicroRNAs (miRNA) are a class of small noncoding RNA molecules that have been implicated in a wide variety of cellular functions through post-transcriptional regulations on target genes. Common genetic variants (single-nucleotide polymorphisms, SNPs) in pre-miRNA genes may alter their expression and/or maturation effecting thousands of target mRNAs, resulting in varied functional consequences. Three common SNPs (hsa-mir-146a G>C rs2910164, hsa-mir-196a2 C>T rs11614913, and hsa-mir-499 T>C rs3746444) in pre-miRNAs were investigated to evaluate their association with urinary bladder cancer risk. The hospital-based case-control study comprised of 212 histologically confirmed patients with urinary bladder cancer and 250 healthy controls who were unrelated, of similar ethnicity, and age and gender matched. Genotyping was done using polymerase chain reaction-restriction fragment length polymorphism methodology. Our results showed that the heterozygous genotype of rs11614913 was higher in cases than controls but the results were marginally significant (p = 0.055; odds ratio, 1.44). Smoking had no impact in modulating the effect of any of the three miRNA SNPs studied. No association was observed with either the tumor stage or grade in patients with bladder cancer. Even though there was no association between the individuals carrying the variant genotypes of the three miRNA studied and bladder cancer risk, marginal significance of heterozygousity in rs11614913 suggested further characterization of miRNA SNPs in a large cohort of varied ethnicity. This could further provide new prospects for understanding the underlying mechanisms between miRNAs and disease etiology.

Role of Oxalobacter formigenes in Calcium Oxalate Stone Disease: A Study from North India

OBJECTIVE The present study was performed to detect the presence of an oxalate degrading bacteria Oxalobacter formigenes in the GI tract of calcium oxalate stone patients and normal individuals from North India. Furthermore, the possible relationship of this bacterium with number of stone episodes in this part of the world was also studied. The correlation of the presence or absence of O. formigenes with the urinary oxalate levels was evaluated. METHODS DNA was extracted from the stool samples of 63 calcium oxalate stone formers and 40 normal individuals. Polymerase chain reaction (PCR) was performed using genus specific primers for O. formigenes. The presence of which was confirmed by Southern blotting. Urinary oxalate levels were tested in each patient. RESULTS As shown by PCR and Southern blotting, O. formigenes was present in 65% of normal individuals and in 30% of calcium oxalate stone formers. In patients with three or greater than three stone episodes colonies were present only in 5.6% of patients. Oxalate excretion was less in patients colonized with O. formigenes as compared to those with no colonization. CONCLUSION In North Indian population the absence of O. formigenes can lead to a significant increase in the risk of absorptive hyperoxaluria and resultant recurrent calcium oxalate stone episodes.

Polymorphism of GSTM1 and GSTT1 genes in prostate cancer: A study from North India

The present study was conducted (1) to examine whether the GSTT1- and GSTM1-null genotypes are risk factors for bladder cancer, and (2) to study possible association of tobacco usage and age strata with genotype of these patients. This case control study was undertaken over a period of 19 months and included 106 bladder cancer patients and 182 controls; both patients and controls originated from northern part of India. The GSTT1 and GSTM1 genotypes were identified by multiplex PCR in peripheral blood DNA samples. Genotype frequencies among patients and controls were assessed and the association of the genotypes with smoking habits and gender of the patients were statistically determined by the χ2 test. Frequencies of null genotypes in GSTT1 and GSTM1, were 16% (29/182) and 30% (54/182), respectively, in control individuals. The frequencies of GSTT1- and GSTM1-null genotypes in bladder cancer patients were 26% (28/106) and 40% (42/106), respectively. In conclusion, our study demonstrated that the null genotypes of GSTT1 and GSTM1 were substantially at higher risk for bladder carcinoma compared to the normal healthy controls. The GSTT1- and GSTM1-null genotypes did not show significant association with tobacco usage in bladder cancer patients. However, the null genotypes were statistically significant in female relative to male bladder cancer patients.

Association of interleukin (IL)-4 intron-3 and IL-6 −174 G/C gene polymorphism with susceptibility to end-stage renal disease

Earlier studies suggest that end-stage renal disease (ESRD) is associated with inflammatory state and have become a major cause of morbidity and mortality worldwide. This study speculated the role of interleukins (IL)-2, -4, and -6 cytokines gene polymorphism with risk of susceptibility to ESRD. Polymorphism in IL-2 (−330 T/G, polymerase chain reaction [PCR]-restriction fragment length polymorphism), IL-4 (intron-3, variable number of tandem repeat, variable number tandem repeats analysis), and IL-6 (-174 G/C, amplification refractory mutation system, i.e. ARMS-PCR) were genotyped in 193 ESRD patients and 180 controls. Significant difference was observed in genotype frequencies of IL-4 and IL-6 between ESRD patients and control group (p < 0.001 and p = 0.032, respectively). Patients had higher frequency of homozygous B2B2 genotype (IL-4) than controls (62.7% vs 46.7) and GG genotype of IL-6 (73.1% vs 60.6%). The genotypic frequencies of IL-2 were comparable in patients and controls (p = 0.102). Significant association of IL-4 was also observed in patients with glomerulonephritis (p = 0.001). Combination of low IL-4 and high IL-6 genotypes were significantly associated with ESRD showing the highest risk, i.e. >threefolds risk (odds ratio=3.48, 95%CI=1.88–6.42; p < 0.001) among the four possible combinations taking high IL-4 and low IL-6 as reference. Our study suggests that polymorphism in IL-4 and IL-6 may be associated with susceptibility to ESRD. Further, combined analysis implicated a higher risk in ESRD patients with low IL-4 and high IL-6 producing genotypes. This study provided the basis for defined anti-inflammatory approaches to limit renal disease progression.

Role of Xenobiotic-Metabolizing Enzyme Gene Polymorphisms and Interactions with Environmental Factors in Susceptibility to Gastric Cancer in Kashmir Valley

BackgroundKashmir Valley has elevated incidence rate of gastric cancer (GC) and several environmental, host genetic factors have been suspected for it. Xenobiotic carcinogen exposure and interindividual differences in its cellular metabolism may modulate susceptibility to GC.Aim of the StudyThe aim of this study is to investigate the role of genetic variants of xenobiotic-metabolizing genes with susceptibility to GC in Kashmir Valley.MethodsA case–control study was performed in 303 subjects (108 GC and 195 healthy controls) to analyze the association of polymorphisms in GSTM1, GSTT1, GSTP1, GSTM3, CYP1A1, and CYP2E1 genes in susceptibility to GC in Kashmir Valley. All subjects were genotyped through polymerase chain reaction–restriction fragment length polymorphism.ResultsGSTM1null and CYP2E1c1c2 genotypes imparted risk for GC (odds ratio [OR] = 1.98, 95% confidence interval [95%CI] = 1.22–3.21, P = 0.006 and OR = 2.56, 95%CI = 1.25–5.25, P = 0.010, respectively). GSTM3AB genotype/B allele was found to be associated with low risk for GC. Smokers and high salted tea consumers themselves were at higher risk for GC (OR = 8.98, 95%CI = 5.16–15.62, P = 0.0001 and OR = 14.78, 95%CI = 8.02–27.23, P = 0.0001, respectively). Cancer risk was further enhanced in smokers with the GSTM1null genotype.ConclusionThe results suggest that GSTM1null, GSTM3AB, and CYP2E1c1c2 genotypes modulate the risk of GC whereas GSTM1null genotypes enhance the risk of GC for smokers in the Kashmir population.

Base excision repair pathway genes polymorphism in prostate and bladder cancer risk in North Indian population

PURPOSE Carcinogens causes DNA damage, including oxidative lesions that are removed efficiently by the base excision repair (BER) pathway. Variations in BER genes may reduce DNA repair capacity, leading to development of urological cancers. METHODS This study included 195 prostate cancer (PCa) and 212 bladder cancer (BC) patients and 250 controls who had been frequency matched by age, sex, and ethnicity. We genotyped XRCC1 Exon 6 (C>T), 9 (G>A), 10 (G>A), OGG1 Exon 7 (C>G) and APE1 Exon 5 (T>G) genes polymorphism using PCR-RFLP and ARMS. RESULTS GA of XRCC1 Exon 9 demonstrated increased risk with PCa as well as in BC (p=0.001; p=0.006). Similarly variant containing genotype revealed association with PCa (p=0.031). Haplotype of XRCC1 also associated with significant risk for PCa and BC. The APE1 GG genotype showed a decreased risk of BC (OR=0.25; p=0.017). Variant genotype GG of OGG1 demonstrated significant risk with BC (p=0.028). CONCLUSIONS Our observations suggested increased risk for PCa and BC in case of GA genotype for XRCC1, and variant GG in case of OGG1. However APE1 GG genotype conferred a protective association with BC susceptibility. Larger studies and the more SNPs in the same pathway are needed to verify these findings.

Association of Xenobiotic Metabolizing Enzymes Genetic Polymorphisms With Esophageal Cancer in Kashmir Valley and Influence of Environmental Factors

The Kashmir Valley has an elevated incidence rate of esophageal cancer (EC). Several environmental and genetic factors have been suspected for development of EC. A case-control study was performed in 135 EC patients and 195 healthy controls to analyze association of polymorphisms in glutathione S-transferase (GST) mu (GSTM1), GST theta (GSTT1), GST pi (GSTP1), GSTM3, Cytochrome P450 (CYP)1A1, and CYP2E1 genes with susceptibility to EC as well as their interaction with environmental factors such as smoking and high consumption of salted tea in Kashmir valley. All subjects were genotyped through polymerase chain reaction restriction fragment length polymorphism. Data was statistically analyzed using the chi-square test and logistic regression model. Results showed that GSTP1313 val/val and CYP2E1c1c2 genotypes imparted risk for esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma [EADC; odds ratio (OR) = 3.24, 95% confidence interval (CI) = 1.30–8.05; OR = 4.20, 95% CI = 1.65–10.70], respectively. GSTM3AB genotype/B allele was found to be associated with low risk for EC. Tobacco smoking through hukka (water pipe) and consumption of salted tea itself were high risk factors for developing EC (OR = 21.44, 95% CI = 11.63–39.54; OR = 14.86, 95% CI = 8.41–26.24), and the risks were modulated through the interaction of GSTM3AB, GSTP1val/val genotypes. In conclusion, GSTP1val/val and CYP2E1c1c2 genotypes/c2 allele increased the risk of ESCC and EADC, respectively, in the Kashmiri population; whereas GSTM3AB genotype imparted lower risk for both ESCC and EADC.

Do DNA repair genes OGG1, XRCC3 and XRCC7 have an impact on susceptibility to bladder cancer in the North Indian population?

OBJECTIVE Polymorphisms in DNA repair genes may be associated with altered DNA repair capacity, thereby influencing an individuals susceptibility to smoking-related cancers such as bladder cancer. Therefore, we sought to examine the correlation between single nucleotide polymorphisms in DNA repair genes and bladder cancer. METHODOLOGY We undertook a case-control study of 212 urothelial bladder cancer (UBC) cases and 250 controls to investigate the association between OGG1 (C1245G rs1052133), XRCC3 (C18067T, rs861539) and XRCC7 (G6721T, rs7003908) polymorphisms and bladder cancer susceptibility by PCR-RFLP and the ARMS method. We also investigated gene-environment interactions. RESULTS The OGG1 GG genotype was associated with an elevated risk of urothelial bladder cancer (UBC) (OR, 2.10; p, 0.028). XRCC7 + 6721 GG was also associated with increased susceptibility to UBC (OR, 4.45; p, 0.001). In a recessive model, the OGG1 GG genotype showed an increased risk of TaG(2,3) + T1G(1-3) tumors. Additionally, the OGG1 GG genotype in non-smokers represented a 2.46-fold greater risk (OR, 2.46; p, 0.035) in bladder cancer patients. Subsequent analysis demonstrated more pronounced association of XRCC7 with smokers (OR, 4.39; p, 0.001). XRCC7 also showed increased association with TaG(2,3) + T1G(1-3) tumors and muscle invasive tumors (OR, 3.16; p, 0.001 and OR, 4.24; p, 0.001, respectively). Multiple Cox regression analysis in non-muscle invasive bladder tumor (NMIBT) patients demonstrated an association of the OGG1 GG polymorphism with a high risk of recurrence in patients on cystoscopic surveillance (HR, 4.04; p, 0.013). Subsequently, shorter recurrence-free survival (log rank p, 0.024; CC/GG, 42/24) was observed. CONCLUSION Our data suggest association of a variant (GG) genotype of OGG1 with increased UBC susceptibility and a high risk of tumor recurrence in NMIBT patients on cystoscopic surveillance. XRCC7 G allele carriers (TG+GG) are also at an elevated risk for susceptibility to UBC as evidenced by a high odds ratio throughout the analysis.