Browsing by Author "Zhang, Xuefeng"

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    Genetic variants in the liver kinase B1-AMP-activated protein kinase pathway genes and pancreatic cancer risk.
    (Molecular carcinogenesis, 2019-04-17) Xu, Xinyuan; Qian, Danwen; Liu, Hongliang; Cruz, Diana; Luo, Sheng; Walsh, Kyle M; Abbruzzese, James L; Zhang, Xuefeng; Wei, Qingyi
    The liver kinase B1-AMP-activated protein kinase (LKB1-AMPK) pathway has been identified as a new target for cancer therapy, because it controls the glucose and lipid metabolism in response to alterations in nutrients and intracellular energy levels. In the present study, we aimed to identify genetic variants of the LKB1-AMPK pathway genes and their associations with pancreatic cancer (PanC) risk using 15 418 participants of European ancestry from two previously published PanC genome-wide association studies. We found that six novel tagging single-nucleotide polymorphisms (SNPs) (i.e, MAP2 rs35075084 T > deletion, PRKAG2 rs2727572 C > T and rs34852782 A > deletion, TP53 rs9895829 A > G, and RPTOR rs62068300 G > A and rs3751936 G > C) were significantly associated with an increased PanC risk. The multivariate logistic regression model incorporating the number of unfavorable genotypes (NUGs) with adjustment for age and sex showed that carriers with five to six NUGs had an increased PanC risk (odds ratio = 1.24, 95% confidence interval = 1.16-1.32 and P < 0.0001), compared to those with zero to four NUGs. Subsequent expression quantitative trait loci (eQTL) analysis further revealed that these SNPs were associated with significantly altered mRNA expression levels either in 373 normal lymphoblastoid cell lines (TP53 SNP rs9895829, P < 0.05) or in whole blood cells of 369 normal donors from the genotype-tissue expression project (GTEx) database [RPTOR SNP rs60268947 and rs28434589, both in high linkage disequilibrium (r2  > 0.9) withRPTOR rs62068300, P < 0.001]. Collectively, our findings suggest that these novel SNPs in the LKB1-AMPK pathway genes may modify susceptibility to PanC, possibly by influencing gene expression.
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    Metastatic Renal Cell Carcinoma as Solitary Subcentimeter Polypoid Gastric Mucosal Lesions: Clinicopathologic Analysis of Five Cases.
    (Gastroenterology research, 2018-02-23) Hemmerich, Amanda; Shaar, Mohanad; Burbridge, Rebecca; Guy, Cynthia D; McCall, Shannon J; Cardona, Diana M; Zhang, Xuchen; Lai, Jinping; Zhang, Xuefeng
    The stomach is an uncommon site for metastatic carcinoma. Approximately 6% of renal cell carcinomas (RCCs) may metastasize to the stomach. The majority of the reported metastatic RCCs in the stomach presented as large masses or ulcers greater than a centimeter in size. It is very rare to encounter metastatic RCC as a solitary small polypoid gastric mucosal lesion.In this study, we collected surgical pathology cases of gastric metastasis from RCC that measured 1.0 cm or less at the time of endoscopy. The clinicopathological characteristics were analyzed.Five patients with subcentimeter metastatic RCC involving the gastric mucosa were identified. The clinical presentation for upper endoscopic examination was non-specific. Two of the five patients did not have a known history of RCC. In the three patients with a previous history of RCC, the interval from primary RCC diagnosis to the detection of gastric mucosal metastasis was 5, 6, and 10 years, respectively. Endoscopically, all the lesions were solitary, ranging in size from 0.4 to 1 cm. Histologically, all five cases were of the clear cell type consisting of a bland clear cell proliferation within the lamina propria. Although the tumor cells were relatively bland, the presence of clear cytoplasm, nuclear membrane irregularity, occasional enlarged hyperchromatic atypical nuclei, and destructive growth in the center of the lesion should promote immunohistochemical workup. Immunohistochemically, the RCC cells exhibited at least patchy immunoreactivity for cytokeratin and RCC markers. In two cases, there were many CD68 positive foamy histiocytes intermingled with the tumor cells.Metastatic RCC can rarely present as subcentimeter polypoid gastric mucosal lesions. The remote or unknown history of RCC, the non-specific endoscopic appearance, and the bland histological features may lead to a potential diagnostic pitfall. It is of importance to raise the awareness of such an unusual presentation of metastatic RCC in the stomach and to include metastatic RCC in the differential diagnosis for gastric mucosal polyps with clear cell morphology.
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    Potential Functional Variants in SMC2 and TP53 in the AURORA Pathway Genes and Risk of Pancreatic Cancer.
    (Carcinogenesis, 2019-02-22) Feng, Yun; Liu, Hongliang; Duan, Bensong; Liu, Zhensheng; Abbruzzese, James; Walsh, Kyle M; Zhang, Xuefeng; Wei, Qingyi
    The AURORA pathway participates in mitosis and cell division, and alterations in mitosis and cell division can lead to carcinogenesis. Therefore, genetic variants in the AURORA pathway genes may be associated with susceptibility to pancreatic cancer. To test this hypothesis, we used three large, publically available pancreatic cancer genome-wide association studies (GWASs) datasets (PanScan I, II/III and PanC4) to assess the associations of 7,168 single nucleotide polymorphisms (SNPs) in a set of 62 genes of this pathway with pancreatic cancer risk (8,477 cases and 6,946 controls of European ancestry). We identify 15 significant pancreatic cancer risk-associated SNPs in three genes (SMC2, ARHGEF7 and TP53) after correction for multiple comparisons by a false discovery rate (FDR) < 0.20. Through further linkage disequilibrium analysis, SNP functional prediction and stepwise logistic regression analysis, we focused on three SNPs: rs3818626 in SMC2, rs79447092 in ARHGEF7 and rs9895829 in TP53. We found that these three SNPs were associated with pancreatic cancer risk [odds ratio (OR) = 1.12, 95% confidence interval (CI) = 1.07-1.17 and P = 2.20E-06 for the rs3818626 C allele; OR = 0.76, CI = 0.66-0.88 and P = 1.46E-04 for the rs79447092 A allele; and OR = 0.82, CI = 0.74-0.91 and P = 1.51E-04 for the rs9895829 G allele]. Their joint effect as the number of protective genotypes (NPGs) also showed a significant association with pancreatic cancer risk (trend test P ≤ 0.001). Finally, we performed an eQTL analysis and found that rs3818626 and rs9895829 were significantly associated with SMC2 and TP53 mRNA expression levels in 373 lymphoblastoid cell lines, respectively. In conclusion, these three representative SNPs may be potentially susceptibility loci for pancreatic cancer and warrant additional validation.
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    Three novel genetic variants in NRF2 signaling pathway genes are associated with pancreatic cancer risk.
    (Cancer science, 2019-06) Yang, Wenjun; Liu, Hongliang; Duan, Bensong; Xu, Xinyuan; Carmody, Dennis; Luo, Sheng; Walsh, Kyle M; Abbruzzese, James L; Zhang, Xuefeng; Chen, Xiaoxin; Wei, Qingyi
    Pancreatic cancer (PanC) is one of the most lethal solid malignancies, and metastatic PanC is often present at the time of diagnosis. Although several high- and low-penetrance genes have been implicated in PanC, their roles in carcinogenesis remain only partially elucidated. Because the nuclear factor erythroid2-related factor2 (NRF2) signaling pathway is involved in human cancers, we hypothesize that genetic variants in NRF2 pathway genes are associated with PanC risk. To test this hypothesis, we assessed associations between 31 583 common single nucleotide polymorphisms (SNP) in 164 NRF2-related genes and PanC risk using three published genome-wide association study (GWAS) datasets, which included 8474 cases and 6944 controls of European descent. We also carried out expression quantitative trait loci (eQTL) analysis to assess the genotype-phenotype correlation of the identified significant SNP using publicly available data in the 1000 Genomes Project. We found that three novel SNP (ie, rs3124761, rs17458086 and rs1630747) were significantly associated with PanC risk (P = 5.17 × 10-7 , 5.61 × 10-4 and 5.52 × 10-4 , respectively). Combined analysis using the number of unfavorable genotypes (NUG) of these three SNP suggested that carriers of two to three NUG had an increased risk of PanC (P < 0.0001), compared with those carrying zero to one NUG. Furthermore, eQTL analysis showed that both rs3124761 T and rs17458086 C alleles were associated with increased mRNA expression levels of SLC2A6 and SLC2A13, respectively (P < 0.05). In conclusion, genetic variants in NRF2 pathway genes could play a role in susceptibility to PanC, and further functional exploration of the underlying molecular mechanisms is warranted.