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Aim and Background:
 Gastric cancer is the fourth most common cancer and second leading cause of cancer related death in the world. Survivin gene encodes a protein which is one of the apoptosis inhibitors. It plays an important role in maintaining the gastric mucosa and is vital for normal function of the stomach. It also plays a key role in differentiation of gastric the epithelial cells and repairs the gastric mucosa after damage. This gene is widely expressed in the gastric stomach, its expression increase significantly in gastric cancer. Regarding role of survivin gene in gastric cancer, in the present study, the association of single- nucleotide polymorphism (rs2071214) A9194G in exon 4 survivin gene with risk of gastric cancers is investigated.
Material and methods:
In this study, 101 patients with gastric cancer and 101 healthy subjects as the control (all matched in terms of age and gender) were examined by PCR-RFLP technique. The obtained data and information were analyzed by statistical regression logestic and ² testes.
 Results:
 The results of this study showed that different genotypes of polymorphism A9194G and alleles are not significantly associated with gastric cancer.
Conclusion:
Our results have shown that there isn’t an association between A9194G polymorphism with the risk of gastric cancer.

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Aim and Background: The HMGA2 protein is one of the transcription factors that regulates the evolution and differentiation of the cells. Studies have shown that changes in the expression of the HMGA2 gene can play an important role in preventing tumor progression and its metastasis. In this study, we investigated the association between rs10573247 polymorphism in the 3-UTR region of HMGA2 gene and the risk of gastric cancer.
Material and Methods: Genomic DNA from blood sample of 100 patients with gastric cancer and 100 healthy individuals were extracted A part of the HMGA2 gene, including rs10573247 polymorphism, was amplified by PCR technique. After, the PCR product was treated with EaR1 enzyme and the genotype of each individual was determined. Finally, the risk of gastric cancer was assessed with the statistical tests of χ2 and logistic regression.
Results: The statistical analysis of allelic and genotypic association of rs10573247 polymorphism with the risk of gastric cancer showed that there was not significant relationship between different alleles of rs10573247 polymorphism (P = 0.127) and none of its genotypes with gastric cancer risk.
Conclusion: It seems none of the rs10573247 polymorphism genotypes in the HMGA2 gene were associated with the risk of gastric cancer.

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Aims and Background: Gastric cancer is one of the most common cancers with high mortality. B7-H4 has been identified as potential novel diagnostic biomarker in gastric cancer. But, its clinical significance in this area is still unclear. The purpose of the present study was to examine the expression level of B7-H4 mRNA in tumor tissue of gastric cancer patient with and without history in comparison with their marginal tissue. Also we evaluate its role in tumor progression and prognosis.  
Materials and Methods: In this study, paraffin blocks were studied from 60 patients with gastric adenocarcinoma (30 with metastasis at the time of diagnosis and 30 without evidence of metastasis) who underwent gastrectomy during 1387-97 in Imam Khomeini Hospital in Tehran. Samples were taken from paraffin blocks by punching method (including tumor and tumor margin for each sample) after the area was identified by the pathologist. RNA extraction was performed from tumor sections and tumor margins. B7-H4 mRNA expression was assessed by quantitative Real-time polymerase chain reaction (qRT-PCR).
Results: Increased expression of B7-H4 mRNA was observed in 81.5% of tumor tissues. There was a significant difference in B7-H4 mRNA expression in tumor tissues of cases with metastasis (p <0.001) and without metastasis (p <0.003) compared to tumor margin. However, comparison of B7-H4 mRNA expression between tumor tissues of metastatic and non-metastatic individuals did not show a significant difference (p = 0.732). Analyzes did not show a significant relationship between B7-H4 mRNA expression and clinical and histopathological variables.
Conclusion: Our findings indicate the possible role of B7-H4 as a potential diagnostic biomarker in patients with gastric cancer. Although more research is needed in this area.
 

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Aim and Background: Genetic variants are valuable markers for predicting chemotherapy resistance. Thymidylate synthetase is an important enzyme target in gastric cancer patients treated with neoadjuvant 5-fluorouracil-based chemotherapy. Genetic variants in the thymidylate synthetase gene are effective in gene expression and resistance to chemotherapy in gastric cancer patients. Therefore, the aim of this study is to investigate the variants of the TYMS gene and the possible effect of their alleles on drug resistance, survival, and gene expression in gastric cancer patients.
Materials and Methods: Genetic analysis was performed on normal sections of paraffin blocks of 100 patients. All patients received neoadjuvant chemotherapy based on 5-fluorouracil. The genotypes of rs34743033 (TYMS 28-bp VNTR) and rs2853542 (TYMS SNP C>G) variants were determined, and gene expression was investigated in tumor tissue and tumor margins of patients
Results: A significant association between TYMS 28 bp VNTR genotypes and treatment was observed (P=0.003). Patients with the 2R3R genotype showed a better response to treatment. The highest and lowest survival times were observed for the 3R3R and 2R2R genotypes, respectively (P=0.003). There was a significant relationship between gene expression and the TYMS 28 bp VNTR variant and the TYMS SNP C>G variant (P<0.001). The CC genotype of the TYMS SNP C>G variant was associated with lower gene expression and the CG genotype was associated with higher gene expression.
Conclusion: This study showed that determining the genotypes and expression of the TYMS gene can be effective for predicting the survival of gastric cancer patients and their response to 5-fluorouracil-based chemotherapy.