Elevated homocysteine level is an independent risk factor for ischemic stroke, thrombotic and cardiovascular diseases. The enzyme methylenetetrahydrofolate reductase (MTHFR) plays a crucial role in regulating the levels of homocysteine. A C677T mutation in this gene results in reduced activity. Sixty-nine patients with arterial stroke, six patients with venous stroke (confirmed by computed tomography and/or magnetic resonance imaging) with hyperhomocysteinemia were selected for the study. Forty-nine subjects with no past history of stroke served as controls. MTHFR genotypes were determined by PCR using specific primers, followed by restriction digestion and gel analysis. The prevalence of the mutated homozygous and heterozygous C677T MTHFR genotype in the patients with arterial stroke was 1.4% (one of 69) and 31.88% (21 of 69), respectively. There frequency was 16.6% (one of six) and 33.3% (two of six) in venous stroke. The genotyping results from controls showed that there was only one heterozygote out of the 49 studied (2.08%). There was a significant difference between the control and the patient groups. Odds ratio for the probability of the C677T MTHFR gene mutation in the patients versus control group was 22.29 (95% CI 4.89-98.8). This indicates that C677T MTHFR mutation is strongly associated with arterial stroke especially in young adults. MTHFR allele evaluation will help in preventing/reducing morbidity caused by stroke.

Esophageal cancer has been associated with tobacco and alcohol consumption, gastric reflux, exposure to nitrosamines from food or other environmental sources, and diets lacking folate. Susceptibility to esophageal cancer may be modified by functional polymorphisms in genes along the folate metabolic pathway, such as methylenetetrahydrofolate reductase (MTHFR). The C677T polymorphism is the most common functional variant, leading to a reduction in enzyme activity. We report a pooled analysis of 5 studies on the association of MTHFR C677T polymorphism and esophageal cancer, including 725 cases and 1531 controls. A significant association between the MTHFR 677 TT genotype and esophageal cancer was observed (OR = 2.63, 95% CI: 1.75–3.94), although there was significant heterogeneity between studies. A sensitivity analysis excluded one study; the association between TT genotype and esophageal cancer was still present, although of reduced magnitude (OR = 1.57, 95% CI: 0.96–2.56). A significant interaction between smoking and TT genotype on esophageal cancer risk was observed, while no interaction was observed between alcohol consumption and genotype.

Cancer development is associated with genetic instability. Identification of specific loci altered during carcinogenesis in a particular tissue gives scope for early detection and predicting the progressive nature of the tissue pathology. Instability at microsatellite loci is widely attributed to mismatch repair errors due to epigenetic alterations. Using three dinucleotide markers, D3S1313, D9S171, D17S250 and two mononucleotide markers BAT25, BATRII, we evaluated MSI in 97 cases enrolled for endoscopy of upper GI tract with symptoms of dyspepsia, reflux or dysphagia. We aimed at evaluating markers that reflect instability in esophageal malignancies, examine the prevalence of MSI in cancers and other pathologies of the esophagus, and determine the methylation status of hMLH1 gene in relation to MSI. 42% (21/50) cancers and 15.4%(2/13) precancers exhibited MSI where 85.7% cancers and 50% precancers with MSI, showed a hypermethylated hMLH1 promoter. Increased number of cases with repair gene methylation were seen with increasing severity of the esophageal pathology suggesting epigenetic progression parallels histologic changes. BAT25 and D3S1313 markers exhibited instability frequently and cases with MSI using these markers showed an abnormal hMLH1 promoter. Thus these markers were useful in identifying the mismatch repair phenotype. These two markers may be useful to screen cases for early cancer related changes, after validation on a larger sample.

The aim of the study was to evaluate the expression of tumor suppressor genes p53, fragile histidine triad gene (FHIT), and an oncogene insulin-like growth factor 2 (IGF2) as prognostic markers in the etiology of esophageal cancer. Immunohistochemistry (IHC) was performed in 39 archival tissue samples of different esophageal pathologies for the three genes. Abnormal p53 expression was maximum in all the cases of squamous cell carcinoma, while IGF2 expression was enhanced in squamous cell carcinoma (81%), adenocarcinoma (100%), and dysplasia of squamous epithelium (75%) samples when compared with normals (50%). To our surprise, 75% of normal tissues did not show FHIT expression, which was also not seen in 40% of dysplasias of squamous epithelium, 33.3% of adenocarcinoma, and 41% of squamous cell carcinoma. To the best of our knowledge, this is the first study evaluating IGF2 by IHC, as well as, correlating it with the expression of the two tumor suppressor genes, p53 and FHIT, in esophageal tissue. p53 expression was threefold higher than normal in dysplasias of squamous epithelium and adenocarcinoma, while it was eightfold higher in squamous cell carcinoma. IGF2 expression was low in normal and dysplasia tissue but was increased 1.97-fold in both types of malignancy. FHIT and p53 expression were well correlated in squamous cell carcinoma, supporting the observation that FHIT regulates and stabilizes p53. Altered/lowered FHIT levels may be a result of exposure to various exogenous agents; however, this could not be assessed in the present study as it was carried out on archival samples. A larger prospective study is warranted to establish the role of exogenous factors in FHIT expression.

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