Strong association of interleukin-6 -174G/C promoter single nucleotide polymorphism with a decreased risk of colorectal cancer in ethnic Kashmiri population: A case control study.

Chronic inflammation increases the risk of development of various cancers, including colorectal cancer. Interleukin-6 has been described as a key regulator of colorectal cancer development and is important in the process of colorectal tumorigenesis largely through the regulation of tumor-promoting inflammation. Several studies have reported the association of various polymorphisms in human interleukin-6 gene including IL-6 -174G/C single nucleotide polymorphism with various cancers, including colorectal cancer, but the results are mixed and inconclusive. The aim of this study was to analyze the association of IL-6 -174G/C promoter single nucleotide polymorphism with colorectal cancer risk and also to evaluate the modifying effects of possible IL-6 -174G/C single nucleotide polymorphism genotypes on different risk factors of colorectal cancer or the reciprocal effect in ethnic Kashmiri population through a case control setup. The genotype frequencies of IL-6 -174G/C promoter single nucleotide polymorphism were compared between 142 colorectal cancer patients and 184 individually matched healthy controls by using polymerase chain reaction-restriction fragment length polymorphism method. The association between the IL-6 -174G/C single nucleotide polymorphism and colorectal cancer risk was examined through conditional logistic regression models adjusted for multiple possible confounding (third) variables. The possible effect measure modification of the association between the relevant single nucleotide polymorphism genotypes and colorectal cancer risk by various colorectal cancer risk factors including age, gender, and smoking status was also evaluated. Furthermore, the associations between these single nucleotide polymorphisms and various clinicopathological parameters, demographic variables, and environmental factors within the case group subjects with regard to colorectal cancer risk were also analyzed. The overall association between the IL-6 -174G/C single nucleotide polymorphism and the modulation of colorectal cancer risk was found to be highly significant (p = 0.001). The variant genotype (CC) was significantly associated with a decreased risk of colorectal cancer (odds ratio, 0.15 (95% confidence interval, 0.04-0.54); p = 0.004). Furthermore, the less common IL-6-174C allele was associated with a decreased risk of colorectal cancer (odds ratio, 0.49 (95% confidence interval, 0.33-0.73); p = 0.0006). The combined variant genotype (GC + CC) was also significantly associated with a decreased risk of colorectal cancer (odds ratio, 0.54 (95% confidence interval, 0.33-0.89); p = 0.015). This study demonstrates that there is a strong and highly significant association between the IL-6 -174G/C promoter single nucleotide polymorphism and a decreased risk of colorectal cancer in ethnic Kashmiri population. However, in order to substantiate our findings, this study needs to be replicated with larger sample size and with other ethnically defined populations with comparable colorectal cancer incidence.

Analysis of molecular aberrations of Wnt pathway gladiators in colorectal cancer in the Kashmiri population.

The development and progression of colorectal cancer (CRC) is a multi-step process, and the Wnt pathways with its two molecular gladiators adenomatous polyposis coli (APC) and ß-catenin plays an important role in transforming a normal tissue into a malignant one. In this study, we aimed to investigate the role of aberrations in the APC and ß-catenin genes in the pathogenesis of CRC in the Kashmir valley, and to correlate it with various clinicopathological variables. We examined the paired tumour and normal-tissue specimens of 86 CRC patients for the occurrence of aberrations in the mutation cluster region (MCR) of the APC gene and exon 3 of the ß-catenin gene by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and/or PCR-direct sequencing. Analysis of promoter hypermethylation of the APC gene was also carried out using methylation-specific PCR (MS-PCR). The overall mutation rate of the MCR of the APC gene among 86 CRC cases was 12.8 per cent (11 of 86). Promoter hypermethylation of APC was observed in 54.65 per cent (47 of 86) of cases. Furthermore, we found a significant association between tumour location, tumour grade and node status and the methylation status of the APC gene (p ≤ 0.05). Although the number of mutations in the APC and ß-catenin genes in our CRC cases was very low, the study confirms the role of epigenetic gene silencing of the pivotal molecular gladiator, APC, of the Wnt pathway in the development of CRC in the Kashmiri population.

SMAD4--molecular gladiator of the TGF-beta signaling is trampled upon by mutational insufficiency in colorectal carcinoma of Kashmiri population: an analysis with relation to KRAS proto-oncogene.

BACKGROUND: The development and progression of colorectal cancer has been extensively studied and the genes responsible have been well characterized. However the correlation between the SMAD4 gene mutations with KRAS mutant status has not been explored by many studies so far. Here, in this study we aimed to investigate the role of SMAD4 gene aberrations in the pathogenesis of CRC in Kashmir valley and to correlate it with various clinicopathological variables and KRAS mutant genotype. METHODS: We examined the paired tumor and normal tissue specimens of 86 CRC patients for the occurrence of aberrations in MCR region of SMAD4 and exon 1 of KRAS by PCR-SSCP and/or PCR-Direct sequencing. RESULTS: The overall mutation rate of mutation cluster region (MCR) region of SMAD4 gene among 86 patients was 18.6% (16 of 86). 68.75% (11/16) of the SMAD4 gene mutants were found to have mutations in KRAS gene as well. The association between the KRAS mutant genotype with SMAD4 mutants was found to be significant (P = or < 0.05). Further more, we found a significant association of tumor location, tumor grade, node status, occupational exposure to pesticides and bleeding PR/Constipation with the mutation status of the SMAD4 gene (P = or < 0.05). CONCLUSION: Our study suggests that SMAD4 gene aberrations are the common event in CRC development but play a differential role in the progression of CRC in higher tumor grade (C+D) and its association with the KRAS mutant status suggest that these two molecules together are responsible for the progression of the tumor to higher/advanced stage.

Promoter methylation and Ile105val polymorphism of GSTP1 gene in the modulation of colorectal cancer risk in ethnic Kashmiri population.

BACKGROUND: Glutathione-S-transferases (GSTs) are the most important phase II enzymes of the xenobiotic pathway responsible for the detoxification of carcinogens. GSTP1 gene polymorphisms are mostly associated with a lack or an alteration of enzymatic activity toward several substrates thus resulting in increased cancer susceptibility. GSTP1 promoter methylation is also frequently associated with tumor development or poor prognosis in a wide range of tumors. AIM: In this study, we examined the role of genetic polymorphism and promoter methylation of GSTP1 gene in the context of modulation of risk of colorectal cancer (CRC) in Kashmiri population. METHODS: This study used tissue tumor samples (114) and blood samples from (160) patients with CRC and 200 blood samples from healthy donors. GSTP1 polymorphism was studied using polymerase chain reaction (PCR)-restriction fragment length polymorphism and methylation using methylation-specific PCR. RESULTS: There was no significant association between GSTP1 I105V genotypes and the CRC (P>0.05). However, we found a significant association of the Val/Val variant genotype with the dwelling and smoking status (P-value < 0.05). Overall, the homozygous variant Val/Val genotype was associated with a modestly elevated risk for CRC (OR = 1.57; 95% CI = 0.67-3.57). Methyl-specific-PCR analysis revealed 25.4% methylation of the GSTP1 promoter in CRC cases and was not found to be statistically significantly associated with clinicopathological parameters of the CRC cases (P>0.05). Also, no significant associations of any of the three genotypes with promoter hypermethylation were observed. CONCLUSION: We conclude that promoter hypermethylation in homozygous GSTP1 mutants did not elevate the risk of CRC in Kashmiri population.

Interleukin-10 -592C/A, but not -1082A/G promoter single nucleotide polymorphism, is associated with a decreased risk of colorectal cancer in an ethnic Kashmiri population: a case-control study.

Chronic inflammation influences the development of various cancers including colorectal cancer (CRC). Interleukin-10 (IL-10), an anti-inflammatory cytokine, plays a vital role in several homeostatic physiological processes occurring in the human gastrointestinal tract including intestinal inflammation and is a key regulator of several gastrointestinal tract pathophysiological processes such as inflammatory bowel diseases that are associated with an increased predisposition to CRC. Several studies have reported the association of various polymorphisms in the human IL-10 gene including IL-10 -592C/A and IL-10 -1082A/G single nucleotide polymorphisms (SNPs) with various cancers including CRC, but these SNPs are yet to be studied in a Kashmiri population with respect to CRC risk. The aim of this study was to analyze the association of IL-10 -592C/A and IL-10 -1082A/G promoter SNPs with CRC risk in an ethnic Kashmiri population through a case-control design. The genotype frequencies of IL-10 -592C/A and IL-10 -1082A/G promoter SNPs were compared between 142 CRC patients and 184 individually matched healthy controls using the PCR and restriction fragment length polymorphism method. The association between the IL-10 -592C/A and IL-10 -1082A/G SNPs and CRC risk was examined through conditional logistic regression models adjusted for multiple possible confounding (third) variables. The possible effect measure modification of the association between the relevant SNP genotypes and CRC risk by various CRC risk factors including age, sex, and smoking status was also evaluated. Further, the associations between these SNPs and various clinicopathological parameters, demographic variables, and environmental factors in the case group patients with respect to CRC risk were also analyzed. The overall association between the IL-10 -592C/A SNP and the modulation of CRC risk was found to be significant (P=0.001). The variant genotype (AA) was significantly associated with a decreased risk of CRC (odds ratio: 0.25; 95% confidence interval: 0.11-0.61; P=0.002). Further, the less common IL-10 -592A allele was associated with a decreased risk of CRC (odds ratio: 0.64; 95% confidence interval: 0.46-0.88; P=0.0092). The overall association between the IL-10 -1082A/G SNP and the modulation of CRC risk was not found to be significant (P=0.141). This study has shown that there is a significant association between the IL-10 -592C/A promoter SNP and a decreased risk of CRC in an ethnic Kashmiri population, but the association between IL-10 -1082A/G SNP and the risk of CRC in the population under study is not significant. However, to substantiate our findings, this study needs to be replicated with a larger sample size and with other ethnically defined populations with comparable CRC incidence.

Matrix metalloproteinase (MMP) -2, -7 and -9 promoter polymorphisms in colorectal cancer in ethnic Kashmiri population - A case-control study and a mini review.

Matrix metalloproteinases (MMPs) are proteolytic enzymes that play a pivotal role in the transformation and progression of tumors at all stages, especially during the invasion and metastasis. The aim of this study was to determine the genetic association of MMP2, MMP7 and MMP9 promoter polymorphisms with colorectal cancer (CRC) susceptibility and development risk in ethnic Kashmiri population. The genotype frequencies of MMP2-1306C/T, MMP7-181A/G and MMP9-1562C/T SNPs were compared between 142 CRC patients and 184 healthy controls by using PCR-RFLP method. The association between all the three MMP promoter polymorphisms and the modulation of risk of CRC was found to be significant (p≤0.05). The heterozygous genotype (CT) of MMP2-1306C/T SNP and variant genotype (GG) of MMP7-181A/G SNP showed a significant association with decreased risk for the development of CRC [OR, 0.61 (95%CI, 0.37-1.01); p=0.05 and OR, 0.43 (95%CI, 0.20-0.90); p=0.02, respectively] whereas the heterozygous genotype (CT) of MMP9-1562C/T SNP showed a significant association with increased risk for the development of colorectal cancer [OR, 1.88 (95%CI, 1.11-3.18); p=0.02]. Further, the less common MMP9-1562T allele was found to be significantly associated with an increased risk of colorectal cancer [OR, 1.74 (95%CI, 1.15-2.62); p=0.007]. Our results suggest that these MMP2, MMP7 and MMP9 promoter polymorphisms play a role as one of the key modulators of the risk of developing colorectal cancer in Kashmiri population.

Tumor necrosis factor-α (TNF-α)-308G/A promoter polymorphism in colorectal cancer in ethnic Kashmiri population - A case control study in a detailed perspective.

BACKGROUND: Inflammation constitutes one of the important components of colorectal cancer (CRC) pathogenesis. Tumor necrosis factor-α (TNF-α), a cytokine and an important inflammatory mediator plays a pivotal role in the malignant cellular proliferation, angiogenesis, tissue invasion and metastasis in CRC. The studies on association of various polymorphisms in human TNF-α gene including TNF-α-308G/A single nucleotide polymorphism (SNP) are limited, mixed and inconclusive. MATERIALS AND METHODS: The aim of this study was to analyze the association of TNF-α-308G/A promoter SNP with colorectal cancer (CRC) susceptibility and development risk and also to evaluate the modifying effects of possible TNF-α-308G/A genotypes on different risk factors of CRC in ethnic population of Kashmir, India through a case-control setup. The genotype frequencies of TNF-α-308G/A promoter SNP were compared between 142 CRC patients and 184 individually matched healthy controls by using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method. The associations between the TNF-α-308G/A SNP and CRC risk were examined through conditional logistic regression models adjusted for multiple possible confounding (third) variables. Further, the associations between this SNP and various clinico-pathological parameters, demographic variables and environmental factors within the case group subjects with regard to CRC risk were also evaluated. RESULTS: The association between the TNF-α-308G/A SNP and the modulation of risk of CRC was not found to be significant (p value = 0.156). The effect of less common TNF-α-308A allele on the risk of colorectal cancer was also not found to be significant (p value = 0.175). The variant genotype (AA) was nonexistent in the study population. Further, we found no significant effect modulation of CRC risk by wild and heterozygous TNF-α-308G/A SNP genotypes in presence of different possible risk factors (p > 0.05). We also found no significant association of TNF-α-308G/A SNP with the subsets of various characteristics of the case group subjects under study (p > 0.05). CONCLUSIONS: This study indicates that there is no significant association between the TNF-α-308G/A promoter SNP and the risk of developing CRC in ethnic Kashmiri population. However, in order to substantiate our findings, this study needs to be replicated with bigger sample size and should involve other ethnically defined populations with high CRC risk.

Polymorphism of the DNA Repair Gene XRCC1 (Arg194Trp) and its role in Colorectal Cancer in Kashmiri Population: a Case Control Study.

BACKGROUND: Genetic polymorphisms in DNA repair genes may influence individual variation in DNA repair capacity, which may be associated with risk of developing cancer. For colorectal cancer the importance of mutations in mismatch repair genes has been extensively documented. MATERIALS AND METHODS: In this study we focused on the Arg194Trp polymorphism of the DNA repair gene XRCC1, involved in base excision repair (BER) and its role in colorectal cancer in Kashmiri population. A case-control study was conducted including 100 cases of colorectal cancer, and 100 hospital-based age- and sex-matched healthy controls to examine the role of XRCC1 genetic polymorphisms in the context of colorectal cancer risk for the Kashmiri population. RESULTS: Genotype analysis of XRCC1 Arg194Trp was conducted with a restriction fragment length polymorphism (RFLP) method. The overall association between the XRCC1 polymorphism and the CRC cases was found to be significant (p<0.05) with both the heterozygous genotype (Arg/Trp) as well as homozygous variant genotype (Trp/Trp) being moderately associated with the elevated risk for CRC [OR=2.01 (95% CI=1.03-3.94) and OR=5.2(95% CI=1.42-19.5)] respectively. CONCLUSIONS: Our results suggest an increased risk for CRC in individuals with XRCC1 Arg194Trp polymorphism suggesting BER repair pathway modulates the risk of developing colorectal cancer in the Kashmiri population.

XRCC3 Thr241Met gene polymorphism and risk of colorectal cancer in Kashmir: a case control study.

XRCC (X-ray cross-complementing group) genes contribute to important DNA repair mechanisms that play roles in the repair of single strand breaks (SSBs) induced by a variety of external and internal factors, including ionizing radiation, alkylating agents and reactive oxygen species. These repair genes have a pivotal role in maintaining genomic stability through different pathways of base excision repair (BER). The aim of this study was to investigate the XRCC3 Thr241Met gene polymorphism in colorectal cancer (CRC) in Kashmir. We investigated the genotype distribution of XRCC3 gene in 120 CRC cases in comparison with 150 healthy subjects and found a significant association between XRCC3 genotypes and CRC (p≤0.05). Both heterozygous genotype (Thr/Met) as well as homozygous variant genotype (Met/Met) were moderately associated with elevated risk of CRC [OR=2.53; OR=2.29 respectively]. Also, Thr/Met and Met/Met genotypes demonstrated a significant association with the risk of CRC (p=0.003). This study displayed a significantly elevated risk for CRC in individuals with XRCC3 Thr/Met and Met/Met Genotype of about 2.5 times that with the Thr/Thr wild genotype.

Arg399Gln polymorphism of XRCC1 gene and risk of colorectal cancer in Kashmir: A case control study.

The aim of this study was to investigate the role of the XRCC1 Arg399Gln polymorphism in the susceptibility of a Kashmiri population to colorectal cancer (CRC). We investigated the genotype distribution of the XRCC1 gene in 130 CRC cases in comparison with that of 150 healthy subjects. There was no direct significant association between the XRCC1 genotypes and CRC; however, the Arg/Gln genotype was associated with an elevated risk of CRC (OR>1.47) and the Gln/Gln variant genotype was associated with an increased risk of CRC in various clinicopathological parameters. This study suggests that the XRCC1 polymorphism is associated with an increased risk of CRC.

Cyclin D1 G870A polymorphism and risk of colorectal cancer: a case control study.

The present study aimed to analyse the role of cyclin D1 A870G polymorphism in modulating the susceptibility to colorectal cancer (CRC) in the Kashmiri population. The genotype distribution of the cyclin D1 gene in 130 CRC cases in comparison with 160 healthy controls was investigated. No direct significant association between cyclin D1 genotypes and CRC was observed; however, the AG and AA genotypes were found to be associated with an increased risk of CRC compared to the GG genotype, with an almost 2-fold increase in OR. This study suggests that the cyclin D1 polymorphism is associated with an increased risk of CRC in the Kashmiri population.

DNA repair gene 8-oxoguanine DNA glycosylase Ser326Cys polymorphism and colorectal cancer risk in a Kashmiri population.

8-Oxoguanine DNA glycosylase (OGG1) is one of the important base excision repair enzymes that repair 8-oxoguanine lesion incorporated within the DNA of an individual by reactive oxygen species. The aim of this study was to detect the role of OGG1 Ser326Cys polymorphism in susceptibility to colorectal cancer (CRC) in a Kashmiri population. We investigated the genotype distribution of the OGG1 gene in 114 CRC cases in comparison with 200 healthy subjects. There was no significant association between OGG1 Ser326Cys polymorphism and CRC, but the homozygous Cys/Cys variant genotype was associated with an increased risk of colon cancer (p<0.05). This study suggests that the OGG1 polymorphism is not associated with the risk of development of CRC in the Kashmiri population in general but modulates the risk of cancer development in colon via interaction with many dietary factors.

The blues of P(16)INK(4a): aberrant promoter methylation and association with colorectal cancer in the Kashmir valley.

Hypermethylation of the promoter region of the p16INK4a (p16) gene plays a significant role in the development and progression of colorectal cancer (CRC). The aim of the present study was to establish the role of the methylation status of the p16 gene in 114 CRC cases and to correlate it with the various clinicopathological parameters. Analysis of p16 promoter methylation was performed by methylation-specific PCR. Forty-eight (42.1%) of the CRC cases were found to be methylated for the p16 gene in our population. The methylation status was found to be associated with the gender, lymph node status, tumour stage, smoking status and tumour grade of the CRC patients. p16 plays a pivotal role in tumour development and progression to advanced stages.

A Rare Case of FAP in Kashmir Valley.

Familial adenomatous polyposis (FAP) is the commonest form of inherited form of CRC. It comprises of about 5% of all the colorectal cancers (CRCs). FAP patients have a family history of CRC that suggests a genetic contribution, common exposures among family members, or a combination of both. This case report gives a glimpse of the phenotypic manifestation of FAP and the underlying molecular mechanism which leads to FAP, in addition it also sheds a light on the management of FAP in early stages of life.

Squamous cell carcinoma of rectum presenting in a man: a case report.

BACKGROUND: Primary squamous cell carcinomas of the colorectum are very uncommon. Until now, to the best of our knowledge, only 114 cases of squamous cell carcinoma in the colorectum exist in the reported literature. Here we report a case of squamous cell carcinoma of the rectum in the ethnic Kashmiri population in northern India. CASE PRESENTATION: The case of a 60-year-old male patient (Asian) with a pure squamous cell carcinoma of the rectum is presented here. The patient underwent a curative surgery with concomitant chemotherapy. Two years after the initial curative resection of the tumor he is still alive. CONCLUSION: The prognosis for squamous cell carcinoma of the colorectum is worse than for that of adenocarcinoma, because of the delayed diagnosis. The etiopathogenicity of squamous cell carcinoma of the colorectum is discussed. Surgical resection of the lesion seems to be the treatment of choice. Chemotherapy also helps in improvement of the prognosis.

Mutational profile of the CAV-1 gene in breast cancer cases in the ethnic Kashmiri population.

The role of caveolae and the caveolin proteins in cancer has been the subject of extensive research. It has been suggested that Caveolin-1 may contribute to certain steps of carcinogenesis in various types of cancer. Therefore in our study we focused on the potential clinical relevance of Caveolin-1 in 130 malignant breast tissue specimens along with their adjacent normal tissues. Using allele specific PCR we were able to rule out the mutation status of all the samples and then we did the conventional PCR-SSCP and sequencing of the mutated samples along with the normal adjacent tissues. Caveolin-1 was identified in a screen for genes involved in breast cancer progression and we demonstrated 29.2% mutational status in our Kashmiri ethnic population. We were able to detect 38 mutations out of which 22 were missense, 4 were nonsense, and 12 were frame shifts. Ten novel Cav-1 mutations (missense and frameshift). We conclude that the gene encoding CAV-1 plays an important role in the promotion of mammary tumorigenesis in Kashmir.

Caveolin-1 promotes mammary tumorigenesis: mutational profile of the Kashmiri population.

BACKGROUND: The role of caveolae and the caveolin proteins in cancer has been the subject of extensive research. It has been suggested that caveolin-1 (Cav-1) may contribute to certain steps of carcinogenesis. In the present study we focused on its potential clinical relevance in mammary malignancies. METHODS: We investigated 130 breast cancer samples along with adjacent normal tissues using allele specific PCR for the mutation status and then conventional PCR-SSCP and sequencing of mutated samples along with the normal adjacent tissues. RESULTS: Caveolin-1 was identified in a screen for genes involved in breast cancer progression and we demonstrated 29.2% mutational status in our Kashmiri ethnic population. We were able to detect 38 mutations out of which 22 were missense, 4 were nonsense, and 12 were frame shifts amongst these 38 we were also able to detect ten novel Cav-1 mutations (missense and frameshift mutations). CONCLUSION: We conclude that our study suggests that the gene encoding Cav-1 plays an important role in the promotion of mammary tumorigenesis and are associated with the development and progression of breast cancer.