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The association of TP53 codon 72 polymorphism with cancer susceptibility remains uncertain and varies with ethnicity. Northeast India represents a geographically, culturally, and ethnically isolated population. The area reports high rate of tobacco usage in a variety of ways of consumption, compared with the rest of Indian population. A total of 411 cancer patients (161 lung, 134 gastric, and 116 oral) and 282 normal controls from the ethnic population were analyzed for p53 codon 72 polymorphism by polymerase chain reaction-restriction fragment length polymorphism. No significant difference in genotypic distribution of p53 between cases and controls was observed. Results suggested betel quid chewing as a major risk factor for all the three cancers (odds ratio [OR] = 3.54, confidence interval [CI] = 2.01-6.25, p < 0.001; OR = 1.74, CI = 1.04-2.92, p = 0.03; and OR = 1.85, CI = 1.02-3.33, p = 0.04 for lung, gastric, and oral cancers, respectively). Tobacco smoking was associated with risk of lung and oral cancers (OR = 1.88, CI = 1.11-3.19, p = 0.01 and OR = 1.68, CI = 1.00-2.81, p = 0.04). Interactions between p53 genotypes and risk factors were analyzed to look for gene-environment interactions. Interaction of smoking and p53 genotype was significant only for oral cancer. Interactions of betel quid with p53 genotypes in lung cancer showed significant increase for all the three genotypes, indicating a major role of betel quid (OR = 5.90, CI = 1.67-20.81, p = 0.006; OR = 5.44, CI = 1.67-17.75, p = 0.005; and OR = 5.84, CI = 1.70-19.97, p = 0.005 for Arg/Arg, Arg/Pro, and Pro/Pro, respectively). In conclusion, high incidence of these cancers in northeast India might be an outcome of risk habits; further, tissue- and carcinogen-specific risk modification by p53 gene is probable. [ABSTRACT FROM AUTHOR]

Background and Aim: Microsomal epoxide hydrolase 1 ( EPHX1) is involved in the metabolism of environmental and tobacco carcinogens. Tobacco smoking, betel quid chewing, and alcohol consumption are the major known risk factors for esophageal cancer. The present case-control study evaluated the influence of EPHX1 genetic variations on esophageal cancer susceptibility in 142 patients and 185 healthy controls from a high-incidence region of India where tobacco use and alcohol consumption are widespread and the users of these two substances are also betel quid chewers. Methods: EPHX1 polymorphic alleles (exon 3, Tyr113His and exon 4, His139Arg) were genotyped by polymerase chain reaction-restriction fragment length polymorphism method and direct sequencing. The results were analyzed using logistic regression to calculate odds ratios (OR) and confidence intervals (CI). Results: Patients with exon 4 genotypes (139His/Arg, 139Arg/Arg) and the 139Arg allele were significantly associated with a risk of esophageal cancer (ORHis139Arg 1.887, 95% CI = 1.112-3.201, P = 0.019; ORArg139Arg 7.140, 95% CI = 1.276-393.953, P = 0.025 and ORArg 1.83, 95% CI = 1.19-2.82, P = 0.003). The 139His/Arg genotype was a significant risk factor for esophageal cancer in tobacco chewers and betel quid chewers. Patients with the 139Arg/Arg genotype were at significantly higher risk for developing a well-differentiated and moderately-differentiated grade of tumor. In contrast, the 113His/His genotype of exon 3 was a significant protective factor for esophageal cancer in tobacco smokers (OR 0.291, 95% CI = 0.138-0.616, P = 0.001), betel quid chewers (OR 0.434, 95% CI = 0.236-0.797, P = 0.007), and alcohol users. Conclusion: EPHX1 exon 4 139His/Arg, and 139Arg/Arg genotypes were associated with a higher risk of esophageal cancer in a high-risk area of India. [ABSTRACT FROM AUTHOR]

The IL-1β -511 C/T polymorphism is associated with increased IL-1 production and with increased risk of developing cancers. In this study, 251 patients (125 with gastric cancer [GC] and 126 with oral cancer [OC]) and 207 normal controls from northeast (NE) India were genotyped for the IL-1β -511 C/T polymorphism by PCR–restriction fragment length polymorphism (RFLP) and sequencing. Analysis of results showed betel-quid chewing to be a major risk factor (OR = 2.01, 95% CI = 1.05–3.87; P = 0.035) for OC. Inheritance of the IL-1β –511 CT or TT resulted in a 2.6- to 3.05-fold increase in the risk of developing OC relative to that of participants who possessed the reference genotype (OR = 2.57, 95% CI = 1.06–6.22; P = 0.036 and OR = 3.05, 95% CI = 1.22–7.63; P = 0.017), after adjusting for potential confounders. The dominant genetic model also confirmed the presence of the T allele as a significant risk factor for OC (OR = 2.72, 95% CI = 1.15–6.42; P = 0.02). In GC, interaction of the CT genotype with tobacco and betel-quid chewing habits conferred a significant 78% and 89% reduced risk of cancer, respectively. In conclusion, for the NE Indian population, the IL-1β –511 CC and CT genotypes were significantly associated with increased risk of OC. However, the interaction of the CT genotype with risk habits may play a preventive role for GC but not for OC. [Copyright &y& Elsevier]