No abstract

Single nucleotide polymorphisms (SNPs) in putative microRNA (miRNA) target sites (miRSNPs) could affect the binding of miRNA with the target and contribute to the susceptibility of human cancers. However, the role of miRSNPs in gastric cancer susceptibility remains largely unknown. Since the over-expression of B7-H1 protein has been reported to be closely related to disease progression of gastric cancer, we investigated the possible role of miRSNPs at the 3'-untranslated region (3'-UTR) of B7-H1 in the risk of developing gastric cancer. In this association study on 205 gastric adenocarcinoma patients and 393 non-cancer controls, we found that the genotype distribution of a common C>G polymorphism (rs4143815) was significantly different between the cases and controls (P = 1.32 × 10(-8)). Compared with CC homozygotes, GG homozygotes and G allele carriers showed 3.73-fold (P = 2.98 × 10(-8)) and 1.85-fold (P = 0.002) increased risk of gastric adenocarcinoma, respectively. Stratified analyses indicated that variant genotypes had a strong association with the clinic-pathological features of gastric cancer including differentiation grade, depth of tumor infiltration, and tumor node metastasis (TNM) stage (P < 0.001). Luciferase reporter assay indicated that this SNP might be responsible for aberrant B7-H1 protein expression in gastric cancer by disrupting the interaction between miR-570 and B7-H1 mRNA. These results are consistent with our hypothesis and indicate that genetic polymorphisms influencing B7-H1 expression modify cancer susceptibility.

The aim of this study is to assess the validity of combined use of fasting plasma glucose (FPG) and glycated hemoglobin A1c (HbA1c) as screening tests for diabetes and impaired glucose tolerance (IGT) in high-risk subjects. A total of 2,298 subjects were included. All subjects underwent a 75-g oral glucose tolerance test (OGTT) and HbA1c measurement. Receiver operating characteristic curve (ROC curve) analysis was used to examine the sensitivity and specificity of FPG and HbA1c for detecting diabetes and IGT, which was defined according to the 1999 World Health Organization (WHO) criteria. (1) Based on the ROC curve, the optimal cut point of FPG related to diabetes diagnosed by OGTT was 6.1 mmol/l that was associated with a sensitivity and specificity of 81.5 and 81.0%, respectively; The optimal cut point of HbA1c related to diabetes diagnosed by OGTT was 6.1%, which was associated with a sensitivity and specificity of 81.0 and 81.0%, respectively; The screening model using FPG > or = 6.1 mmol/l or HbA1c > or = 6.1% had sensitivity of 96.5% for detecting undiagnosed diabetes; the screening model using FPG > or = 6.1 mmol/l and HbA1c > or = 6.1% had specificity of 96.3% for detecting undiagnosed diabetes. (2) Based on the ROC curve, the optimal cut point of FPG related to IGT diagnosed by OGTT was 5.6 mmol/l that was associated with a sensitivity and specificity of 64.1 and 65.4%, respectively; The optimal cut point of HbA1c related to IGT diagnosed by OGTT was 5.6%, which was associated with a sensitivity and specificity of 66.2 and 51.0%, respectively; The screening model using FPG > or = 5.6 mmol/l or HbA1c > or = 5.6% had sensitivity of 87.9% for detecting undiagnosed IGT; The screening model using FPG > or = 5.6 mmol/l and HbA1c > or = 5.6% had specificity of 82.4% for detecting undiagnosed IGT. Compared with FPG or HbA1c alone, the simultaneous measurement of FPG and HbA1c (FPG and/or HbA1C) might be a more sensitive and specific screening tool for identifying high-risk individuals with diabetes and IGT at an early stage.

Inhibitory costimulatory molecule CD274 expresses in various cancers and contributes to cancer immune evasion by inhibiting T cell activation and proliferation, yet the regulatory mechanisms for CD274 overexpression in cancers are poorly understood. In this study, we discovered a novel mechanism of CD274 expression regulated by miR-570. A guanine-to-cytosine mutation at the 3'-UTR of CD274 mRNA led to CD274 overexpression by disrupting the miR-570 binding. The mutations were widely observed in cancers by sequencing of 276 gastrointestinal cancers (esophageal, gastric, colorectal, hepatocellular, and pancreatic cancers). This mutation was significantly associated with CD274 overexpression in gastric cancer (P = 1.44×10(-10)) and with the pathological features including differentiation grade, depth of tumor invasion, lymph node metastasis, and tumor-node-metastases (TNM) stage. These findings suggest a novel regulatory mechanism for CD274 overexpression in gastric cancer mediated by miR-570 and a somatic mutation in CD274 3'-UTR, and provide a new insight to gastric carcinogenesis.