Dil Afroze

Role of TP53 Arg72Pro polymorphism in urinary bladder cancer predisposition and predictive impact of proline related genotype in advanced tumors in an ethnic Kashmiri population

Among various polymorphic variants of TP53 gene, codon 72 polymorphism (Arg72Pro) has been found to be associated with cancer susceptibility, but only few studies have investigated their effect on bladder cancer risk. A case-control study was conducted and we observed the genotype distribution of TP53 Arg72Pro SNP, to elucidate the possible role of this SNP as risk factor in urinary bladder cancer (UBC) development and to examine its correlation with the clinicopathologic variables of UBC cases. Using the polymerase chain reaction-restriction fragment length polymorphism approach, we tested the genotype distribution of 108 bladder cancer patients in comparison with 138 cancer-free controls from the same geographical region. We observed significant differences between the control and bladder cancer patients with odds ratio = 2.9 and 95% confidence interval = 1.5-4.5 (P = 0.00001). Interestingly, the proline form was abundantly observed in advanced tumors (P < 0.05). We also found a significant association of the variant allele (GC+CC) with male subjects and ever smokers (P = 0.001). Thus, it is evident from our study that Arg72Pro SNP is implicated in bladder cancer, and that the rare, proline-related allele is connected with higher susceptibility to bladder cancer.

Promoter Methylation Status of DNA Repair Gene (hMLH1) in Gastric Carcinoma Patients of the Kashmir Valley

Cancer is a multi-factorial disease and variation in genetic susceptibility, due to inherited differences in the capacity to repair mismatches in the genome, is an important factor in the development of gastric cancer (GC), for example. Epigenetic changes, including aberrant methylation of 5/CpG islands in the promoter regions of mismatch repair (MMR) genes like hMLH1, have been implicated in the development of various types of GC. In the present study we evaluated the role of hMLH1 promoter hypermethylation in Kashmiri GC patients and controls, and assessed correlations with various dietary and lifestyle factors. The study included 70 GC patients (56 males and 14 females; age (mean ± S.D) 50 ± 11.4 years). Distinction between methylated and unmethylated was achieved with MS-PCR and DNA band patterns. The Chi-square test was applied to assess the risk due to promoter hypermethylation. We found a strikingly high frequency of promoter hypermethylation in GC cases than in normal samples (72.9% (51/70) in GC cases vs 20% (14/70) in normal samples (p=0.0001). We also observed a statistically significant association between methylated hMLH1 gene promoter and smoking, consumption of sundried vegetables and hot salted tea with the risk of GC. This study revealed that hMLH1 hypermethylation is strongly associated with GC and suggested roles for epigenetic changes in stomach cancer causation in the Kashmir valley.

Study of TLR4 and IL-8 Gene Polymorphisms in H.pylori-Induced Inflammation in Gastric Cancer in an Ethnic Kashmiri Population

Background: TLRs play an essential role in the initial handling of H. pylori and determine the clinical outcomes that range from simple asymptomatic gastritis to peptic ulcer disease and gastric cancer. Asp299Gly and Thr399Ile polymorphisms in TLR4 have been associated with a variety of inflammatory and infectious conditions including gastric cancer. The T-251A polymorphism in the promoter region of IL-8 gene has been found to be associated with changing the in vitro levels of IL-8 production. IL-8 exhibits angiogenic activity and is responsible for tumor-associated angiogenesis in several cancers. Materials and methods: 130 gastric cancer patients and 200 healthy controls were included in this study. DNA extraction was followed by PCR detection of H. pylori infection, PCR-RFLP for the TLR 4 polymorphism and PCR-CTPP for IL-8 gene polymorphism. Results: The adjusted OR for gastric cancer risk was 1.15 (95% CI, 0.8357–1.3463); 1.39 (0.6964-2.781) and 1.43 (0.954–2.1515) for Asp299Gly, Thr399Ile and IL-8 T_251A respectively. Odds Ratio analysis showed CT genotype and AT and AA genotypes as risk factors for the development of gastric cancer. We found the Asp299Gly polymorphism carrier to be significantly associated (p value 0.03)with the development of tumours in the distal part of the stomach and Thr399Ile polymorphism to be significantly associated(p value 0.008) with the development of well-differentiated gastric adenocarcinoma.The IL-8 T-251A polymorphism was not found to be associated with any of the clinicopathological characteristics. Discussion: No correlation was found between the appearance of disease and HP infection or the presence of TLR4 and IL-8 gene polymorphisms and HP infection.

Serum Leptin Levels, Leptin Receptor Gene (LEPR) Polymorphism, and the Risk of Systemic Lupus Erythematosus in Kashmiri Population

The study is conducted to evaluate relationship between LEPRQ223R (Gln > Arg) polymorphism, serum leptin levels, soluble leptin receptor (SOb-R) levels and SLE risk in Kashmiri population.LEPR genotyping was done by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method in 100 unrelated SLE patients and equal number of healthy control subjects. Leptin and SOb-R levels were measured by ELISA assays. The present study showed higher frequency of variant genotype (AG + GG) in cases compared to controls [OR = 2.52, CI = 1.18–5.35, p = 0.03]. Moreover the rare (G) allele was significantly more predominant in cases than controls [OR = 1.49, p = 0.04]. Interestingly a positive association between the variant genotype and the development of arthritis [OR = 11.8, CI = 1.6–85.1, p = 0.002] and an inverse association with cardiac disorder [OR = 0.09, CI = 0.02–0.46, p = 0.001] was observed in this study. Furthermore the study showed significant differences of leptin levels in SLE patients and controls (23.9 ± 19.5 vs 14.8 ± 10.4, p < 0.001). SLE patients in the highest quartile leptin levels (≥32.5 ng/mL) were significantly more likely to have higher BMI (p = 0.001) and increased risk of developing arthritis (p = 0.02). Furthermore positive association was observed between the variant genotype(AG + GG) and leptin levels (p = 0.001) in SLE patients. Thus, it is evident from our study that LEPRQ223R polymorphism and elevated leptin levels are associated with increased susceptibility of SLE in Kashmiri population.

C242T polymorphism of the NADPH oxidase p22PHOX gene and its association with endothelial dysfunction in asymptomatic individuals with essential systemic hypertension

Vascular oxidative stress is an important factor in hypertension-associated vascular damage and is mediated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation. The C242T polymorphism at the p22PHOX gene affects binding of p22PHOX to heme, leading to variants of NADPH oxidase that produce different levels of reactive oxygen species (ROS). Specific variations in ROS are associated with an altered risk of developing cardiovascular disease. In the present study, 140 permanent Kashmiri-resident individuals were recruited (75 with essential systemic hypertension and 65 normotensive controls). Endothelial function was assessed non-invasively using high-resolution ultrasonography of the brachial artery. Endothelium-dependent vasoreactivity was expressed in terms of flow-mediated dilation. The TT genotype was identified in 2% of hypertensive and 7% of normotensive individuals. Frequency of the T-allele was not observed as significantly different between hypertensive and normotensive individuals (P=0.24; OR=0.4; 95% CI, 0.07-2.2). Blood pressure or the prevalence of hypertension did not vary between C242T p22PHOX genotypes or in the presence or absence of the T-allele.

WITHDRAWN: Single nucleotide polymorphisms, haplotype association and tumour expression of the vascular endothelial growth factor (VEGF) gene with lung carcinoma.

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Trp homozygotes at codon 64 of ADRB3 gene are protected against the risk of type 2 diabetes in the Kashmiri population.

The prevalence of type 2 diabetes mellitus has reached epidemic proportions worldwide. Type 2 diabetes is a consequence of complex interactions among multiple genetic variants and environmental risk factors. Polymorphisms in various candidate genes confer susceptibility to diabetes. This study was undertaken to analyse a single nucleotide polymorphism Trp64Arg (C↔T) in the ADRB3 gene and elucidate its effects on type 2 diabetes and its associated risk factors. The study included 200 type 2 diabetes patients and 300 age and gender matched healthy controls belonging to the ethnic Kashmiri population. Polymerase chain reaction-restriction fragment length polymorphism technique was used for genotyping and the results were validated by direct sequencing assay. Genotypes for Trp64Arg polymorphism were in Hardy-Weinberg equilibrium (χ(2)=0.48, p=NS). Frequency of the Arg64 allele was 40% and 10.2% in cases and controls, respectively (p<0.05; odds ratio 5.89; 95% CI; 3.69-9.39). The Arg64 allele was directly related to higher body mass index, waist-to-hip ratio, dyslipidemia and uncontrolled disease status. The study signifies that the Arg64 allele of the ADRB3 gene is a genotypic risk factor and confers susceptibility to type 2 diabetes, whereas the homozygous Trp64 genotype exerted a protective effect in our population.

Mutational spectrum of conserved regions of TP53 and PTEN genes in Kangri cancer (of the skin) in the Kashmiri population

Kangri cancer is a unique, thermally induced squamous cell carcinoma (SCC) of the skin that develops due to persistent use of a Kangri (a brazier) by the Kashmiri people to combat the cold temperature during winter. Unlike classical UV-induced SCC of the skin, Kangri cancer appears on the legs and abdomen. Its common features are erythematous patches, recurrence and metastasis. In the absence of any molecular etiology, we made a preliminary attempt to estimate the nature and frequency of mutations in the TP53 and PTEN genes in Kangri cancer patients from Kashmir. PCR-SSCP analysis followed by direct sequencing revealed that TP53 mutations account for 40% (12/30) of sporadic Kangri cancer patients and that PTEN mutations account for only 6.6% (2/30). There were 16 mutations in TP53 exons 5 and 7, found in 12 patients. They consisted of 11 substitutions (7 transitions, 3 transversions and 1 double-base) and 5 insertions. The 11 substitutions represent 8 distinct missense mutations, 3 of which were silent mutations. The mutations detected in the PTEN gene consisted of one insertion and one C>T transition. This high percentage of TP53 mutations (especially A>G) showed a statistically significant association with age and positive lymph node status. Our results indicate that TP53 is a predominant target of chronic hyperthermia in the development of Kangri cancer in the moderate risk Kashmiri population. The differences in the TP53 mutation spectrum of UV-induced SCC of the skin and Kangri cancer are probably due to the nature of the respective environmental carcinogens. The study also suggests that TP53 may function as a potential molecular marker and prognostic tool, at least in a subset of sporadic Kangri tumors.

Genetic Variation of ApoE Gene in Ethnic Kashmiri Population and Its Association with Outcome After Traumatic Brain Injury

The outcome from traumatic brain injury (TBI) is variable and only partly explained by known prognostic factors. Genetic factors may influence the brain’s susceptibility to injury or capacity for repair and regeneration. ApoE has been implicated in modifying neurological outcome after TBI, although the mechanisms by which this occurs remain poorly defined. Apolipoprotein E is an apparently multifunctional protein involved in the response of the brain to injury and in subsequent repair processes. Several studies have shown that patients with APOE e4 have a poorer outcome after TBI. This study was aimed to analyse the genotypes of ApoE in Kashmiri population and to examine the association of APOE genotype with outcome after TBI. A total of 450 subjects (300 healthy controls and 150 TBI patients) were recruited for the study. Genotyping was done by PCR-restriction fragment length polymorphism (RFLP).Our study indicated Apoe3/e3 to be the most common genotype in this study group. The allele frequency of the Apo E gene in these study subjects was observed to be 0.07 for the e2 allele, 0.82 for the e3 allele and 0.11 for the e4 allele. However, no association between the presence of APOe4 allele and outcome after head injury was observed in this study [p = 0.92]. Thus, genotype containing the e4 allele (e4/e3 and e4/e4) was not associated with unfavourable outcome after TBI in Kashmiri population.

SNP and Haplotype Analysis of Vascular Endothelial Growth Factor (VEGF) Gene in Lung Cancer Patients of Kashmir

Vascular endothelial growth factor (VEGF) is a major mediator of angiogenesis involving tumor growth and metastasis. In this large case-control study, we investigated whether functional polymorphisms (+405C>G, +936C>T) in the VEGF gene are associated with the risk of lung cancer. The study investigates the association between variants of VEGF gene and lung cancer. We performed single nucleotide polymorphism (SNP), haplotype and linkage disequilibrium studies on 100 patients and 128 healthy controls with 2 SNPs in the VEGF gene. The results were analyzed using logistic regression models, adjusted for age and sex. No Significant association was detected between individual SNPs and lung cancer using all the models of inheritance (codominant, dominant, recessive, over dominant and additive) for finding an association between genotypes and the cancer risk. The P values obtained for two markers were non-significant (P>0.05). Haplotype analysis produced additional support for the non-association of individual haplotypes/all haplotypes with the cancer risk (Global association P=0.56). Our findings suggest the non-involvement of genetic variants (+405C>G, +936C>T) of the VEGF gene in the etiology of lung cancer.