ABSTRACT
OBJECTIVE: To analyze the correlation between the single nucleotide polymorphisms (SNPs) in the promoter of Piwil1 gene and gastric cancer. METHODS: The expression of Piwil1 mRNA in the tumor tissues of 3 patients with gastric cancer was detected by RT-qPCR, and RNA-Sequencing data from the Cancer RNA-Seq Nexus were analyzed for Piwil1 mRNA expression in gastric patients. Blood samples were collected from 24 gastric cancer patients and 29 healthy control subjects for PCR amplification of Piwil1 gene promoter region. The SNP loci in the promoter region of Piwil1 gene were determined by direct sequencing, and the results were analyzed by SnapGene software. RESULTS: Analysis of the data from Cancer RNA-Seq Nexus and the results of RT-qPCR in 3 gastric cancer patients all showed significantly increased Piwil1 expression in gastric cancer tissues compared with the adjacent tissues. Seven SNP loci in two CpG regions of the Piwil1 gene promoter were genotyped, and only one SNP locus was found to be related to gastric cancer. The frequencies of GG, GA, and AA genotypes at the rs28416520 locus in CpG 67 region were 79.2%, 16.7%, and 4.1% in the gastric cancer group, and were 37.9%, 55.2%, and 6.9% in the control group, respectively, showing a significantly higher frequency of the GG genotype in gastric cancer group (OR=0.144, 95%CI: 0.045-0.564, χ2=9.071, P < 0.01). The frequency of allele G of the rs28416520 locus was significantly higher in gastric cancer group than in the control group (87.5% vs 65.5%; OR=0.271, 95%CI: 0.099-0.766, χ2=6.856, P < 0.01). The genotype or allele frequencies of the other 6 SNPs locus did not differ significantly between gastric cancer group and control group. CONCLUSIONS: The expression of Piwil1 is increased in gastric cancer tissues as compared with the adjacent tissues. The GG genotype and G allele of rs28416520 within CpG 67 region are associated with an increased risk of gastric cancer.
