Nidda Syeed

Molecular Gate Keepers Succumb to Gene Aberrations in Colorectal Cancer in Kashmiri Population, Revealing a High Incidence Area

Background/Aim: Colorectal cancer (CRC) is one of the leading malignancies worldwide and has been reported to show geographical variation in its incidence, even within areas of ethnic homogeneity. The aim of this study was to identify p53 and K-ras gene mutations in CRC patients in a Kashmiri population, and to assess whether these mutations are linked with clinicopathological parameters. Materials and Methods: Paired tumor and normal tissue samples from a consecutive series of 53 patients undergoing resective surgery for CRC were prospectively studied for p53 and K-ras gene mutations by PCR/single strand conformation polymorphism (SSCP). Results: Less than half (45%, 19/42) of the patients presented mutations in the p53 gene. Twenty eight mutations were found in the p53 gene, which comprised of 23 substitutions (17 transitions + 6 transversions), and five insertions. The 23 substitutions constituted 18 missense mutations, two nonsense mutations, and three silent mutations. Of the 28 mutations (7.14%) observed in this study, 2 were not previously reported for CRC samples and were identified as novel p53 mutations. A few patients (22.64%, 12/53) presented with mutations in K-ras, constituting 13 missense mutations, out of which 11 were G→A transitions, one was a G→C transversion, and one a G→T transversion. More than half (61.5%) of the mutations occurred in codon 12 whereas a few (38.5%) occurred in codon 13. One tumor contained missense mutations in both codons. Comparison of the mutation profiles of our patients with those of other ethnic populations and regions reflected both differences and similarities, indicating co-exposure to a unique set of risk factors. Conclusion: Mutations of the p53 and K-ras genes are some of the most common genetic changes in the development of human CRC. The high frequency of p53 gene mutations implicates p53 as a predominant factor for CRC in the high-risk ethnic Kashmiri population.

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

BackgroundThe 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.MethodsWe 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.ResultsThe 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 =< 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 =< 0.05).ConclusionOur 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.

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

BackgroundPrimary 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 PresentationThe 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.ConclusionThe 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.

5`-CpG Island Promoter Hypermethylation of the CAV-1 Gene in Breast Cancer Patients of Kashmir

BACKGROUND Caveolin-1 (CAV-1), encoding the structural component of cellular caveolae, is a suggested tumor suppressor gene involved in cell signalling. Aberrant promoter methylation of CAV-1 is associated with inactivation of expression. We previously observed CAV-1 mutations in breast cancers and therefore devised this study to examine the hypermethylation status of the promoter region of CAV-1 with reference to breast cancer progression and development. METHODS Hypermethylation status of CAV-1 was analyzed by methylation specific PCR. Loss of expression of the CAV-1 gene was further evaluated by semi-quantitative rt-PCR. RESULTS 28/130 (21.5%) breast cancer cases showed promoter hypermethylation with reduced CAV-1 expression levels when compared with adjacent normal breast tissue. CAV-1 gene hypermethylation was significantly related to menopausal status, histopathological grade and age. CONCLUSION The rationale of our study is that CAV-1 gene is transcriptionally repressed in breast cancer cells due to hypermethylation. Our results reveal that promoter hypermethylation and loss of expression of the CAV-1 gene is an important alternative mechanism for inactivation of CAV-1 leading to complete gene silencing.

Polymorphic analysis of MHClinked Heat Shock Protein 70 genes: Their susceptibility and prognostic implication in Kangri cancer cases of Kashmiri population

Kangri cancer is a unique thermally-induced squamous cell carcinoma (SCC) of skin that develops due to persistent use of Kangri (a brazier), used by Kashmiri people, to combat the chilling cold during winter months. We designed a large scale case-control study to characterize the frequency of two polymorphisms within the MHC class III-linked HSP70genes, Hsp70-2 and Hsp70-hom, in order to find any association of these genotypic variants for predisposition to and clinical outcome of Kangri cancer patients from Kashmir valley in North India. Polymerase Chain Reaction and restriction enzymes were utilized to characterize the frequency of two polymorphisms with in Hsp70-2 and Hsp70-hom genes in 118 Kangri carcinoma cases and 95 healthy controls from the same population of Kashmir. Association of high frequency allelic variants of Hsp70genes with various clinicopathological features of prognostic significance was assessed by Chi-square test using SPSS software. In this study, allelic frequency of Hsp70-2 A/G heterozygote (0.87) (P = 0.012) was found to be significantly high in Kangri cancer cases compared to control (0.736) with a Relative Risk of 2.45 fold. Conversely, the allelic frequency of Hsp70-2 A/A allele in homozygous condition was significantly low in Kangri cancer cases and worked out to be 0.084 (Vs 0.252 in control) with P is equal to 0.001, implicating it as a protective allele against Kangri cancer in subjects with this genotype. Similarly, significantly high frequency of 0.50 (Vs 0.29 in control) of Hsp70-homC/C allele was found in homozygous condition in Kangri cancer cases suggestive of a positive relative risk associated with this genotype (RR is equal to 2.47) (P is equal to 0.002). The overall allele frequency data analysis of Hsp70-2 and Hsp70-hom genes was significant (χ2 is equal to 12.38, P is equal to 0.002; and χ2 is equal to 12.21, P is equal to 0.002). The study also reveals considerable association of high frequency alleles of HSP70 genes, especially of Hsp70-2 A/G or G/G in Kangri tumors with clinico-pathological features of poor prognosis. These results indicate that the relative risk of Kangri cancer associated with Hsp70-2 and Hsp70- hom gene polymorphisms is confined to Hsp70-2 A/G or G/G and Hsp70homC/C haplotype in our population. The study, therefore, suggests Hsp70-2 A/G or G/G and Hsp70homC/C genotypes as potential susceptibility markers and independent prognostic indicators in Kangri carcinoma patients in Kashmiri population.

P53- The Molecular Guardian Crashes in Gastric Adenocarcinomas - A Study in an Ethnic Kashmiri Population

Genetic instability underlies the etiology of multistep gastric carcinogenesis. The p53 mutations observed in tumors represent the expression of such instability by allowing the accumulation of genetic alterations caused by multiple mechanisms. The present study was conducted to investigate the nature and frequency of TP53 mutations in patients with gastric adenocarcinomas of Kashmir valley. Tumor samples from 30 patients with primary gastric adenocarcinomas undergoing radical gastrectomy were evaluated. The mutational status of the p53 (exons 5 to 8) was screened by PCR-SSCP analysis followed by direct sequencing. Of all 30 gastric adenocarcinomas including ten intestinal types and twenty diffuse types, 20% patients (6/30) harbored mutations in the p53 gene. Overall, twenty-one mutations were found in TP53 in 30 patients included in this study. Mutations were found at codon 142 (3 cases) of exon 5, codon 144 (1 case) in exon 5, codon 147 (1 case) in exon 5, codon 157 (1 case) in exon 5, codon 169 (2 cases) in exon 5, codon 170 (3 cases) in exon 5, codon 172 (1 case) in exon 5, codon 173 (3 cases) in exon 5, codon 179 (3 cases) in exon 5, codon 180 (1 case) in exon 5, codon 213 (1 case) in exon 6, the insertional mutation was between codon 216 & 217 (1 case) in exon 6 and codon 287 in exon 8 (1 case). The mutation pattern comprised of 12 insertions, 6 substitutions (all transversions) and 3 deletions. All the twelve insertions represented frame-shift mutations. The six single-base substitutions leading to aminoacid substitution included four missense mutations and a single silent mutation. The mutation effect data was found to be significant (p< 0.05). This study exhibited signifi cant amount of mutation in exon 5 (OR=90.25 and p<0.05 within the CI of 12.47-652.89) of TP53 in the gastric adenocarcinoma patients from Kashmir valley. Comparison of mutation profi le with other ethnic populations and regions refl ected both differences and similarities indicating co-exposure to a unique set of risk factors. The differences could be due to exposure to explicit environmental carcinogens, different lifestyle, dietary or cultural practices of Kashmiris being an ethnic population that need further investigations. The direct sequencing results, therefore, shall help in understanding the molecular events associated with progression and metastasis in gastric carcinoma. Conclusions: p53 gene mutation incites the pathogenesis of human gastric adenocarcinomas.

Molecular Enhancers; Remote Controls the Differential Gene Expression during Development

Enhancers are the DNA elements, which belong to class of regulatory sequences that can influence the transcriptional output independently of their location, distance or orientation with respect to the promoter of the genes they control. These regulatory DNA elements throughout the genome monitor the spatial and temporal expression patterns of specific sets of genes during the course of development. In the recent past, various studies suggest that the discrete chromatin characteristics of enhancer sequences are involved in directing the varied signalling molecules to distinct DNA regions that drive the differential gene expression program during the development. These diverse chromatin features contribute to the differential epigenetic patterning of enhancers which is regulated by the complex interaction between the DNA methylation status, the binding of specific transcription factor to enhancers and existing histone modifications. Herein, we present insights into the epigenetic mechanisms of enhancer functions, which eventually contribute to the repertoire of cellular mechanisms to facilitate the altered patterns of gene expression and cell differentiation choices during developmental processes.

ACE gene polymorphism in breast cancer patients of ethnic Kashmiri population

Background: The mitogenic and angiogenic effect of angiotensin II has been shown in breast cancer. Angiotensin II is converted from its inactive form to active form by the angiotensin I converting enzyme (ACE). Materials and Methods: To evaluate the effect of ACE gene in breast cancer patients and its effect on healthy control subjects, we studied 130 breast cancer patients and 220 healthy controls. Results: During our study, we found, the ACE genotype distribution in breast cancer patients were as follows: 62 (47.6%) had Deletion (DD), 43 (33.07%) had ID, and 25 (19.23%) had II (Insertion) genotypes, whereas in controls, 96 (43.63%) had DD, 107 (48.63%) had ID, and 25 (7.7%) had II genotypes. Conclusion: We conclude that our results implicate that ACE level/activity has been suggested to be protective against breast cancer, and therefore renin-angiotensin system may serve as a curative target for breast cancer detection, treatment, and prevention. Impact: Our study is the first report from India on Kashmiri population, suggesting that ACE activity can be a protective tool against breast cancer.

Role if ATM IVS10-6T'G Polymorphism in Breast Cancer; A Case-control Study in High-risk Kashmiri Population

The provenance of ATM candidacy as a susceptible breast cancer gene stems from two sources. The main task of ATM being that the ATM protein is a fundamental participant in mediating cellular responses to DNA damage, including cellular signaling, DNA double-strand break repair and leading to cell-cycle arrest and apoptosis. From the genetic standpoint, ATM is a gene mutated in ataxia-telangiectasia (AT), an autosomal recessive disorder phenotypically characterised by chromosomal instability and an increased risk for lymphoproliferative tumors in homozygotes. Numbers of studies have suggested that heterozygous carriers of ATM mutations are at increased risk of breast cancer and ATM IVS10-6T→G SNP has been reported to significantly increase the breast cancer risk. In order to shed further light on the putative contribution of ATM to breast cancer risk, we performed haplotyping of the ATM locus in high-risk Kashmiri population. The ATM IVS10-6T→G polymorphism was studied in 130 breast cancer patients and 220 female healthy controls using a PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) and conformation by DNA Sequencing. The PCR-RFLP analysis revealed that 68.4% (89 of 130) breast cancer patients were homozygous for T/T variant, 21.5% (28 of 130) patients were heterozygous for T/G variant and 10% (13 of 130) patients were homozygous for GG variant. The present study concludes that the ATM IVS10-6T→G polymorphism is associated with sufficiently high risk of breast cancer and among the breast cancer cases and controls the heterozygous T/G variant determines the higher risk for initiating and developing breast cancer.

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.