L Sadeghi-Amiri - Department of Basic Sciences, Sari Agricultural Sciences and Natural Resources University, Sari, Iran.
N Nikbakhsh-Zati - Department of Surgery, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran.
A Barzegar - Department of Basic Sciences, Sari Agricultural Sciences and Natural Resources University, Sari, Iran.
P Mehraban - Department of Basic Sciences, Sari Agricultural Sciences and Natural Resources University, Sari, Iran.

Introduction and aim: Gastric cancer is one of the most common malignancies in northern Iran with high usage of agricultural pesticides. CYP1A1, as one of the most important prototype of cytochrome P450 detoxifying enzyme superfamily, is epigenetically regulated. Recent studies have remarked the correlation between the methylation of individual CpGs present in the cis-acting elements of certain gene. Method: Paired tissue samples of turmeric as well as its surrounding normal gastric tissues was dissected from patients who were undergone surgery. Genomic DNA extracted using phenol-chloroform method was subjected to bisulfate treatment. Desired region located in CYP1A1 gene promoter were PCR-amplified and were sequenced in Bioneer company. Statistically analyzing was done by Spearman s correlation coefficient.Results: Results showed that CpG dinucleotides are relatively methylated in either normal or turmeric gastric tissues. Statistical analysis revealed that there are significant (positive) correlation between some CpGs in both tissue (P<0.05%).Conclusion: Positive correlation found between the methylation rates of some CpG dinucleotides scattered in a -4167 _ -3746 bp consensus sequence known as xenobiotic response element. Regarding to the importance of respective region in CYP1A1 gene promoter as xenobiotic and transcription factors response elements, correlative methylation rate would change transcription factors affinity leading to differential transcription rate and accordingly possible cancer incidence. Screening methylation pattern of this region may be useful to clarify read-write strategy of DNA methylation.

CYP1A1, DNA methylation, Gastric cancer, Northern Iran.