Liping Dai

Using proteomic approach to identify tumor-associated proteins as biomarkers in human esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers in China. The lower survival rate of ESCC is attributed to late diagnosis and poor therapeutic efficacy; therefore, the identification of tumor-associated proteins as biomarkers for early diagnosis, and the discovery of novel targets for therapeutic intervention, seems very important for increasing the survival rate of ESCC. To identify tumor-associated proteins as biomarkers in ESCC, we have analyzed ESCC tissues and adjacent normal tissues by two-dimensional electrophoresis (2DE) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analysis. The results showed that a total of 104 protein spots with different expression levels were found on 2DE, and 47 proteins were eventually identified by MALDI-TOF MS. Among these identified proteins, 33 proteins including keratin 17 (KRT17), biliverdin reductase B (BLVRB), proteasome activator subunit 1 (PSME1), manganese superoxide dismutase (MnSOD), high-mobility group box-1(HMGB1), heat shock protein 70 (HSP70), peroxiredoxin (PRDX1), keratin 13 (KRT13), and so on were overexpressed, and 14 proteins including cystatin B (CSTB), tropomyosin 2 (TPM2), annexin 1 (ANX1), transgelin (TAGLN), keratin 19 (KRT19), stratifin (SFN), and so on were down-expressed in ESCC. Biological functions of these proteins are associated with cell proliferation, cell motility, protein folding, oxidative stress, and signal transduction. In the subsequent study using immunoassay on ESCC serum samples and tissue-array slides, two representative proteins, HSP70 and HMGB1, were selected as examples for the purpose of validation. The results showed that both HSP70 and HMGB1 can induce autoantibody response in ESCC sera and have higher expression in ESCC tissues. Especially, the frequency of antibodies to HSP70 in ESCC sera was significantly higher than that in normal human sera. The preliminary results suggest that some of these identified proteins might contribute to esophageal cell differentiation and carcinogenesis, certain proteins could be used as tumor-associated antigen (TAA) biomarkers in cancer diagnosis, and further studies on these identified proteins should provide more evidence of how these proteins are involved in carcinogenesis of ESCC.

XRCC1 gene polymorphisms and lung cancer susceptibility: a meta-analysis of 44 case–control studies

X-ray repair cross-complementing group 1 gene (XRCC1) has been implicated in risk for lung cancer. However, the results from different studies remain controversial. In this meta-analysis, we have assessed 44 published case–control studies regarding associations of lung cancer risk with three common polymorphisms, codon 194, codon 280 and codon 399, and −77 Txa0>xa0C in the promoter region of XRCC1. The results in total population showed that the risk for lung cancer was increased among the variant homozygote Trp/Trp of codon 194 polymorphism, compared with the wild type Arg/Arg (OR: 1.19; 95xa0% CI 1.01–1.39), and the variant genotype CC of −77 Txa0>xa0C polymorphism showed a significantly increased risk of developing lung cancer, compared to wild-type genotype TT (OR: 1.91; 95xa0% CI 1.24–2.94). However, no associations were found between lung cancer risk and codon 280, codon 399. In the subgroup analyses by ethnicity, the OR for the variant homozygote Trp/Trp of codon 194 was 1.21(95xa0% CI 1.02–1.43) for Asian. When stratified by source of control, we found a protective effect of codon 194 Arg/Trp genotype (OR: 0.87; 95xa0% CI 0.77–0.98) and risk effect of codon 399 combined Arg/Glnxa0+xa0Gln/Gln variant genotype (OR: 1.09; 95xa0% CI 1.01–1.18) for lung cancer on the basis of hospital control. Subgroup analyses by histological types of lung cancer indicated that the heterozygote Arg/Trp in codon 194 could decrease and the combined variant genotype Arg/Glnxa0+xa0Gln/Gln in codon 399 could increase the risk of non-small cell lung cancer (OR: 0.69; 95xa0% CI 0.57–0.85 and OR: 1.14; 95xa0% CI 1.04–1.24). In conclusion, this meta-analysis has demonstrated that codon 194, codon 399 and −77 Txa0>xa0C polymorphisms of XRCC1 gene might have contributed to individual susceptibility to lung cancer. To further evaluate effect of XRCC1 polymorphisms, gene–gene interaction and gene-environment interaction on lung cancer risk, a single large sample size study with thousands of subjects is required to get conclusive results.

XRCC1 gene polymorphisms and esophageal squamous cell carcinoma risk in Chinese population: A meta-analysis of case―control studies

Two non‐synonymous polymorphisms Arg194Trp and Arg399Gln in the DNA‐base excision repair gene X‐ray repair cross‐complementing group 1 (XRCC1) have been implicated in risk for esophageal cancer. However, the results from different studies remain controversial. The present meta‐analysis of literatures was performed to clarify these associations in Chinese population. A comprehensive literature search was conducted to identify all case–control studies of XRCC1 polymorphisms Arg194Trp and Arg399Gln and risk for esophageal squamous cell carcinoma (ESCC). A total of 9 eligible studies, including 1,538 ESCC cases and 2,472 controls, were identified to the meta‐analysis. The odds ratio (OR) for the variant homozygous genotype Trp/Trp of the Arg194Trp polymorphism, compared with the wild‐type homozygote Arg/Arg, was 1.59 (p = 0.0007), with 95% confidence interval (95% CI) 1.22–2.09, for ESCC risk without between‐study heterogeneity. However, there was no statistically significant associations of ESCC risk in the dominant model Arg/Trp+Trp/Trp (OR 0.97; 95% CI 0.84–1.12; p = 0.69) and heterozygous genotype Arg/Trp (OR 0.90; 95% CI 0.77–1.04; p = 0.16) when comparing with wild‐type genotype Arg/Arg. For Arg399Gln, there was no effect in dominant modeling (Arg/Gln+Gln/Gln vs. Arg/Arg: OR 0.92; 95% CI 0.80–1.06; p = 0.25), and the variant Gln/Gln homozygote was not associated with ESCC risk (OR 1.29; 95% CI 0.79–2.10; p = 0.31), either. In conclusion, Arg194Trp genetic polymorphism may be associated with an increased risk for developing ESCC and a study with the larger sample size is needed to further evaluate gene–environment interaction on XRCC1 polymorphisms and ESCC risk.

Identification of tumor-associated antigens by using SEREX in hepatocellular carcinoma

AIMnTo identify biomarkers for diagnosis and prognosis of hepatocellular carcinoma (HCC).nnnMETHODSnScreening the HCC cDNA library with HCC patients sera. Isolated proteins were used as antigens to detect antibodies from patients with HCC and control sera.nnnRESULTSnEighty-one positive clones were identified. The frequencies of autoantibody against five HCC-associated antigens were higher in HCC than that in chronic hepatitis and normal human sera. The sensitivity and specificity of KRT23, AHSG and FTL antigens combination tests up to 98.2% in joint test and 90.0% in series test separately.nnnCONCLUSIONSnHCC associate antigens identified from this study supply candidate markers of diagnosis, combined detection and immunotherapy of HCC.

Polymorphisms in lncRNA HOTAIR and susceptibility to breast cancer in a Chinese population.

Controversial data have emerged on the association between cancer risk and the single-nucleotide polymorphism (SNP, rs920778C>T) in Hox transcript antisense RNA (HOTAIR). No data on the association between HOTAIR polymorphism and breast cancer (BC) susceptibility and reproductive factors have been reported in China. In this study we investigated the association between HOTAIR polymorphisms and BC susceptibility in a population-based case-control study of 502 cases and 504 matched controls in China. Three haplotype tagging SNPs (rs1899663, rs4759314, rs920778) of HOTAIR were genotyped with polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) and created-restriction-site PCR (CRS-RFLP) assays. False-positive report probability (FPRP) was calculated to test for false-positive associations. Interactions between the SNPs and reproductive factors were further evaluated by the multifactor dimensionality reduction (MDR) method. BC risk reduction was confined to subgroups of age at menarche >14 (OR: 0.42, 95%CI: 0.21, 0.82) and number of pregnancies >2 (OR: 0.65, 95%CI: 0.49, 0.95) for GT+TT rs1899663, and age at menopause ≤ 50 (OR: 0.97, 95%CI: 0.84, 0.99) for AG+GG rs4759314. Subjects with Trs920778 had a significantly increased risk of breast cancer (OR: 1.41, 95%CI: 1.13, 1.75). We observed a significant interaction between rs920778 and reproductive factors, including age at menopause, number of abortions, and family history. Our results were unlikely to be false positives according to FPRP calculation. In conclusion, genetic variant rs920778 in HOTAIR significantly increased the risk of BC, and it may have apparent interaction with reproductive factors in the progression on BC. These findings extend available data on the association between HOTAIR polymorphisms and BC susceptibility.

Inflammatory cytokine gene polymorphisms in gastric cancer cases' and controls' family members from Chinese areas at high cancer prevalence.

The purpose of this study was to test the associations about Helicobacter pylori infection and polymorphisms of IL-1B-31/-511 and IL-1RN VNTR polymorphism with gastric cancer in cases and controls family members from the areas of high cancer prevalence in China. IL-1B-511T and IL-1RN *2 were associated with risks of gastric cancer. The association strength reduced with the relative degree decreasing. Such association was not found in the polymorphisms of IL-1B-31. But the haplotype analysis of IL-1B-511 and IL-1B-31 genotype could enhance the risks of gastric cancer. The positive H. pylori status could increase the risks of IL-1B to gastric cancer.

Novel functional variants locus in PLCE1 and susceptibility to esophageal squamous cell carcinoma: Based on published genome-wide association studies in a central Chinese population

A novel functional single nucleotide polymorphism (SNP) rs2274223 located in the phospholipase C epsilon 1 (PLCE1) gene was found to be associated with the risk of esophageal squamous cell carcinoma (ESCC) by three large-scale genome-wide association studies (GWAS) in Chinese populations. In the present study, we validated this finding and also explored the risk of ESCC associated with other two unreported potentially functional SNPs (rs17417407 G>T and rs2274224 C>G) of PLCE1 in a population-based case-control study to investigate the association between these three potentially functional SNPs in PLCE1 and susceptibility to ESCC. A total of 381 ESCC cases and 420 controls matched by age and sex were recruited and successfully genotyped for three SNPs (rs17417407, rs2274223 and rs2274224) of the PLCE1 in a central Chinese population. SNP rs2274223 was independently associated with increased risk of ESCC (adjusted odds ratio [OR], 2.80; 95% confidence interval [95% CI], 1.45-5.39 for GG vs. AA), and SNP rs2274224 was found to be associated with decreased risk of ESCC (adjusted OR, 0.65; 95% CI, 0.46-0.91 for CG vs. CC). The combined effects of risk alleles for three SNPs (rs17417407T, rs2274223G and rs2274224G) were found to be associated with elevated risk of ESCC in a dose-dependent effect manner (Ptrend=0.005). The Grs17417407Ars2274223Crs2274224 haplotype decreased the risk of ESCC (adjusted OR, 0.76; 95% CI, 0.62-0.93), meanwhile the Grs17417407Grs2274223Crs2274224 and Trs17417407Grs2274223Crs2274224 haplotypes could increase the risk of ESCC (adjusted OR, 1.75; 95% CI, 1.33-2.18 and OR, 2.51; 95% CI, 1.15-2.49). Gene-environment interaction analysis presented a best model consisted of four factors (rs2274223, rs2274224, family history, and smoking) with testing balance accuracy (TBA): 0.66 and cross validation consistency (CVC): 7/10, which could increase the esophageal cancer risk in the high risk group with 3.67-fold (OR: 3.67, 95% CI: 2.74-4.92), compared to the low risk group. Our results further confirmed that genetic variations in PLCE1 may contribute to ESCC risk associated with tobacco exposure in a central Chinese population. Further functional studies are needed to validate our results.

Systematic evaluation of cancer risk associated with DNMT3B polymorphisms

PurposeThe aim of our study is to provide a precise quantification for the association between DNA methyltransferase 3B (DNMT3B) variations (rs2424913 C/T, rs1569686 G/T, rs6087990 T/C and rs2424908 T/C) and the risk of cancer.MethodsWe performed a systematic literature review and assessed the methodological quality of included case–control designed studies based on Newcastle–Ottawa Scale. Pooled odds ratios (ORs) and corresponding 95xa0% confidence intervals (95xa0% CIs) were calculated to assess the strengths of the associations.ResultsWe identified 34 studies for pooled analyses. Overall, the results demonstrated that rs2424913 polymorphism was significantly associated with negative cancer risk in the African population (CT vs TT: OR 0.10, 95xa0% CI 0.02–0.63, Pxa0=xa00.01; CT+CC vs TT: OR 0.14, 95xa0% CI 0.03–0.76, Pxa0=xa00.02), and the rs1569686 polymorphism was significantly associated with a subtly decreased cancer risk (GT vs TT: OR 0.80, 95xa0% CI 0.72–0.90, Pxa0<xa00.01; GT+GG vs TT: OR 0.84, 95xa0% CI 0.76–0.94, Pxa0<xa00.01), particularly in the Asian population (GT vs TT: OR 0.79, 95xa0% CI 0.66–0.96, Pxa0<xa00.01) and in colorectal cancer subgroup (G vs T: OR 0.69, 95xa0% CI 0.54–0.88, Pxa0<xa00.01). In addition, the rs6087990 polymorphism was associated with decreased risk in Asian population (T vs C: OR 0.77, 95xa0% CI 0.62–0.96, Pxa0=xa00.02). Similarly, the rs2424908 polymorphism was observed as a protective factor for cancer in the Asian population (CT+CC vs TT: OR 0.79, 95xa0% CI 0.66–0.95, Pxa0=xa00.01).ConclusionsDNMT3B polymorphisms might be associated with decreased cancer risk especially in the Asian population and for colorectal cancer. Further multicentric studies are still needed to confirm the results.

MicroRNAs related polymorphisms and genetic susceptibility to esophageal squamous cell carcinoma.

Esophageal cancer (EC) is the sixth leading cause of cancer-associated death worldwide and the incidence and mortality in China are the highest. The single nucleotide polymorphisms (SNPs) related to microRNAs could lead to alteration in microRNA expression and contribute to the susceptibility of cancer. To evaluate the association between microRNA-related SNPs and EC, a case–control study including 381 patients with esophageal squamous cell carcinoma (ESCC) and 426 gender, age-matched controls was carried out to investigate the genetic susceptibility of five microRNA-related SNPs (rs2910164 in microRNA-146a, rs11614913 in microRNA-196a-2, rs7813 in GEMIN4, rs1595066 and rs16845990 in ErbB4) as well as the interactions of gene–gene and gene–environment in the development of ESCC. Variant homozygote genotype of rs11614913 in microRNA-196a-2 and rs1595066 in ErbB4 were significantly associated with reduced ESCC risk (ORadjusted: 0.62, 95xa0% CI: 0.39–0.99 and ORadjusted: 0.38, 95xa0% CI: 0.24–0.61). The analysis of haplotypes in ErbB4 gene showed significant increased ESCC risk in Grs1595066Crs16845990 and Grs1595066Trs16845990 haplotypes (ORadjusted: 1.46, 95xa0% CI: 1.08–1.99 and ORadjusted: 1.33, 95xa0% CI: 1.10–1.62), and inversely reduced ESCC risk in Ars1595066Crs16845990 and Ars1595066Trs16845990 haplotypes with OR (95xa0% CI) of 0.75 (0.60–0.94) and 0.65 (0.49–0.86), respectively. These findings suggest that the polymorphisms in the microRNA-related genes may affect susceptibility of ESCC in Chinese Han population and the gene–gene interactions play vital roles in the progression on esophageal cancer. Future studies with larger sample and different ethnic populations are required to support and validate our findings.

Evaluation of miRNA-binding-site SNPs of MRE11A, NBS1, RAD51 and RAD52 involved in HRR pathway genes and risk of breast cancer in China.

MiRNA-binding-site single nucleotide polymorphisms (SNPs) in homologous recombination repair (HRR) pathway genes may change DNA repair capacity and affect susceptibility to cancer though complex gene–gene and gene–reproductive factors interactions. However, these SNPs associated with breast cancer (BC) are still unclear in Chinese women. Therefore, we conducted a case–control study to evaluate the genetic susceptibility of the five miRNA-binding-site SNPs in HRR pathway genes (MRE11A rs2155209, NBS1 rs2735383, RAD51 rs963917 and rs963918 and RAD52 rs7963551) in the development of BC. MRE11A rs2155209 and RAD52 rs7963551 were found to be associated with BC risk (ORadjusted: 1.87; 95xa0% CI: 1.23-2.86 and ORadjusted: 0.36; 95xa0% CI: 0.24-0.58). NBS1 rs2735383, RAD51 rs963917 and rs963918 were associated with BC risk after stratification according to reproductive factors. Haplotypes of Crs963917Ars963918 decreased the risk of BC (ORadjusted: 0.53; 95xa0% CI: 0.4–0.68), while the Trs963917Ars963918 and Trs963917Grs963918 haplotypes could increase the risk of BC (ORadjusted: 1.28; 95xa0% CI: 1.05–1.57 and ORadjusted: 1.31; 95xa0% CI: 1.09–1.62). Combined effect of risk alleles showed that the five SNPs were associated with increased BC risk in a dose-dependent manner (Ptrendxa0=xa00.003). The GC genotype of rs2735383, AGxa0+xa0GG genotype of rs963918 and ACxa0+xa0CC genotype of rs7963551 were associated with PR positivity of BC patients. These findings suggest that the miRNA-binding-site SNPs involved in HRR pathway genes may affect susceptibility of BC in Chinese women; moreover, the interactions of gene–gene and gene–reproductive factors play vital roles in the progression of BC. Further functional studies with larger sample are needed to support and validate these findings.