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Genome-wide association studies (GWASs) have identified multiple single nucleotide polymorphisms (SNPs) associated with colorectal cancer (CRC) susceptibility. However, the elucidation of causal SNPs and the biological mechanisms behind are still limited. In this study, we initially performed systematic bioinformatics analyses on CRC GWAS-identified loci to seek for potential functional SNPs located at transcription factor binding sites (TFBSs), and then a two-stage case-control study comprised of 1353 cases and 1448 controls of Chinese populations and functional analyses were conducted. As a result, only one SNP rs6695837 out of the nine candidate SNPs survived after two-stage analyses by Bonferroni correction. In combined analyses, rs6695837 exhibited significant associations with CRC risk (TT: CC, odds ratio (OR) = 1.31, 95% confidence interval (CI) = 1.06-1.63; dominant model, OR = 1.21, 95% CI = 1.03-1.43; additive model, OR = 1.15, 95% CI = 1.03-1.28). Functional annotations by RegulomeDB and rSNPBase indicated its biological role and dual-luciferase reporter assays revealed a significant increase in luciferase expression for the reconstructed plasmid with rs6695837T allele, compared with the one with C allele (PSW480 = 0.0002, PLovo = 0.0003). Further gene expression analyses demonstrated significantly higher expression of LAMC1 gene in CRC tumor tissues than that in adjacent non-cancerous tissues (P = 0.0004). These findings strongly suggest that the functional SNP located at TFBSs, rs6695837 might contribute to CRC susceptibility, and the exact biological mechanism awaits further research. [ABSTRACT FROM AUTHOR]

Genome-wide association studies (GWASs) have identified multiple susceptibility loci of colorectal cancer (CRC), however, causative polymorphisms have not been fully elucidated. Long non-coding RNAs (lncRNAs) are a recently discovered class of non-protein coding RNAs that involved in a wide variety of biological processes. We hypothesized that single nucleotide polymorphisms (SNPs) in lncRNA may associate with the CRC risk by influencing lncRNA functions. To evaluate the effects of SNPs on CRC susceptibility in Chinese populations, we first screened out all potentially functional SNPs in exons of lncRNAs located in CRC susceptibility loci identified by GWAS. Eight SNPs were selected and genotyped in 875 CRC cases and 855 controls and replicated in an independent case-control study consisting of 768 CRC cases and 768 controls. Analyses showed that CG and GG genotypes of the rs2147578 were significantly associated with increased risk for CRC occurrence in both case-control studies [combined analysis OR = 1.29; 95% confidence interval (CI) = 1.11-1.51, P = 0.001] compared to the rs2147578 CC genotype. Bioinformatics analyses showed that rs2147578 is located in the transcript of lnc- LAMC2-1:1 and could influence the binding of lnc-LAMC2-1:1/miR-128-3p. Further luciferase reporter assays demonstrated that the construct with the risk rs2147578G allele had relatively high expression activity compared with that of the rs2147578C allele. Expression quantitative trait loci analyses also showed that rs2147578 is correlated with the expression of a well established oncogene LAMC2 (laminin subunit gamma 2). These findings indicated that rs2147578 in lnc-LAMC2-1:1 might be a genetic modifier for the development of CRC. [ABSTRACT FROM AUTHOR]

Thymidylate synthase (TS) catalyzes the 5,10-methylene-tetrahydrofolate-mediated conversion of deoxyuridine monophosphate to deoxythymydine monophosphate, a nucleotide required for DNA synthesis and repair. The impaired TS expression has been shown to be related to 28 bp tandem repeats and a G?C SNP in the 5'-UTR of TS. Folate deficiency has been demonstrated to play a role in gastroesophageal carcinogenesis. This casecontrol study was to examine the hypothesis that the TS polymorphisms, alone or in combination with serum folate status, may confer susceptibility of the hosts to gastroesophageal cancer. We analyzed TS genotype and serum folate concentration in 324 patients with esophageal squamous cell carcinoma (ESCC), 231 patients with gastric cardia adenocarcinoma (GCA) and 492 controls. It was found that compared with the normal expression TS genotype, the low expression TS genotype alone was significantly associated with increased risk of ESCC [adjusted odds ratio (OR) 1.47; 95% confidence interval (CI) 1.032.10] but not GCA (OR = 0.98, 95% CI = 0.681.40). More importantly, a significant interaction between the TS polymorphisms and serum folate status in risk of ESCC and GCA was observed. Among subjects with low serum folate concentration (<3 ng/ml), the ORs of ESCC and GCA for the low expression genotype were 22.63 (95% CI = 10.4449.05) and 4.08 (95% CI = 1.948.59), which were greater than respective 9.97 (95% CI = 5.6717.53) and 1.88 (95% CI = 1.183.24) for the normal expression genotype (P = 0.002 and 0.029). These results suggest an important role for folate deficiency and impaired TS activity in the etiology of ESCC and GCA. [ABSTRACT FROM AUTHOR]

STK15 (Aurora-A) is a serine/threonine kinase involved in mitotic chromosomal segregation. A genetic variant in STK15T+91A (resulting in the amino acid substitution F31I) is associated with increased aneuploidy in colon tumors and cell transformation in vitro. Since this polymorphism plays a role in mitotic controla process critical for all cancer typeswe conducted association analyses for risk of cancer development of the colon, breast, prostate, skin, lung and esophagus in 10 independent casecontrol populations. We carried out a meta-analysis of these 10 casecontrol studies together with 5 additional published studies for a total of 9549 cases of breast, colon, ovarian, prostate, lung, esophageal and non-melanoma skin cancer and 8326 population or hospital-based controls. Meta-analysis of three colorectal cancer studies showed an increased risk in T+91A homozygotes (OR = 1.50; 95% CI of 1.141.99). Meta-analysis of four breast cancer studies showed increased risk for T+91A homozygotes (OR = 1.35, 95% CI of 1.121.64). The results of the multiple cancer type meta-analysis for all 15 studies combined were significant for cancer risk in both homozygotes and heterozygotes. The T+91A heterozygotes show an OR of 1.10 (95% CI of 1.031.18, P-value = 0.006) and the T+91A homozygotes show an OR of 1.40 (95% CI of 1.221.59, P-value <0.001) for cancer risk. These results confirm that the STK15T+91A variant is a low penetrance cancer susceptibility allele affecting multiple cancer types, and provide genetic evidence from large-scale human population studies that genetic stability at the chromosome level is an important determinant of cancer susceptibility. The data also underline the advantages of comparative association studies involving study populations from different ethnic groups for determination of disease risk. [ABSTRACT FROM AUTHOR]

Aurora-A/BTAK/STK15, involved in regulating centrosomes and chromosome segregation, is overexpressed in human breast carcinoma and other cancers. The Phe31?Ile polymorphism in Aurora A alters the kinase function, with the Ile31 variant being preferentially amplified and associated with degree of aneuploidy in human tumors. We have previously shown that the Phe31Ile polymorphism is associated with the occurrence and advanced disease status of esophageal cancer. This casecontrol study examined the contribution of this polymorphism to susceptibility to development and progression of breast cancer. Aurora A genotypes were determined in 520 patients with breast carcinoma, 191 patients with benign breast diseases (BBD) and 520 controls. It was found that the Aurora AIle/Ile genotype was significantly associated with increased risk of breast carcinoma occurrence [odds ratio (OR) 1.66; 95% confidence interval (95% CI) 1.292.12] compared with the Phe/Phe or Phe/Ile genotype. The increased risk for BBD and breast carcinoma related to the Ile/Ile genotype was more pronounced in younger subjects. Moreover, we found that patients carrying the Ile/Ile genotype tended to have ERcarcinomas (OR 2.56; 95% CI 1.245.26). No significant association was observed between the polymorphism and metastasis and disease stage of the cancer. These findings suggest that the Phe31Ile polymorphism in Aurora A may be a genetic modifier for developing breast carcinoma. [ABSTRACT FROM AUTHOR]

Background: The FAS receptor-ligand system is a key regulator of apoptotic cell death, and loss of FAS expression and gain of FAS ligand (FASL) expression play important roles in the development and progression of cancer. Single nucleotide polymorphisms in the promoter region of the FAS (G or A at position -1377 [FAS -1377G/A] and A or G at position -670 [FAS -670A/G]) and FASL (T or C at position -844 [FASL -844T/C]) genes alter the transcriptional activity of these genes. We examined the association between these polymorphisms and risk of the development and metastasis of esophageal squamous-cell carcinoma. Methods: Genotypes of 588 case patients with esophageal squamous cell carcinoma and 648 control subjects were determined by polymerase chain reaction-based restriction fragment length polymorphism. Associations with the risk of esophageal squamous-cell carcinoma were estimated by logistic regression. All statistical tests were two-sided. Results: We observed a statistically significantly increased risk of esophageal squamous-cell carcinoma associated with the FAS -1377AA (odds ratio [OR] = 1.79, 95% confidence interval [CI] = 1.29 to 2.48; P<.001) or FAS -670GG (OR = 1.72, 95% CI = 1.26 to 2.34; P<.001) genotype, which are in strong linkage disequilibrium compared with the FAS -1377GA or GG or the FAS -670AG or AA genotype, respectively. An increased risk of esophageal squamous-cell carcinoma was also associated with the FASL -844CC genotype (OR = 2.06, 95% CI = 1.64 to 2.59; P<.001) compared with the FASL -844CT or TT genotype. Gene-gene interactions of FAS and FASL polymorphisms increased the risk of esophageal squamous-cell carcinoma in a multiplicative manner (OR for the presence of both FAS -1377AA and FASL -844CC genotypes = 4.55, 95% CI = 2.75 to 7.48; P = .001, test for homogeneity). Statistically significant interactions were found between these polymorphisms in FAS and FASL and tobacco smoking. None of the polymorphisms was associated with risk of differentiation or metastasis of esophageal squamous-cell carcinoma at diagnosis. Conclusion: Genetic polymorphisms in the death pathway genes FAS and FASL appear to be associated with an increased risk of developing esophageal squamous-cell carcinoma. [ABSTRACT FROM AUTHOR]

The matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) have been shown to play important roles in multiple ways in all stages of cancer initiation and development. Single nucleotide polymorphisms identified in the promoters of MMP2 (-1306C?T) and TIMP2 (-418G?C) abolish the Sp1-binding site and thus may down-regulate expression of the genes. This casecontrol study examined the contribution of these functional polymorphisms to susceptibility to development and metastasis of breast cancer. MMP2 genotypes were determined by PCR-based denaturing high performance liquid chromatography analysis and TIMP2 genotypes identified by a PCR-RFLP method in 462 breast cancer patients and 509 frequency matched control women. We found that the variant MMP2 genotype (-1306CT or TT) was associated with substantially reduced risk of breast cancer [odds ratio (OR), 0.46; 95% confidence interval (95% CI), 0.340.63], compared with the CC genotype. For TIMP2, a moderately reduced risk of the cancer (OR, 0.76; 95% CI, 0.580.99) was also associated with the variant allele (-418GC or CC), compared with the GG common allele. Furthermore, it seemed that the polymorphisms in the two genes had some additive effect and the reduced risk related to the polymorphisms appeared to be more pronounced in younger subjects. However, no significant associations were observed between the polymorphisms in the two genes and tumor stage and metastasis of the cancer at the time of diagnosis. These findings suggest that the presence of the variant allele in the promoter of MMP2 or TIMP2 may be a protective factor for the development of breast cancer. [ABSTRACT FROM AUTHOR]

Tumor growth and metastasis require that tumor cells must have either the potential to shift genetically or epigenetically between proliferative and invasive phenotypes or both phenotypes simultaneously. In the present study, we demonstrated that neuroblastoma growth and invasion were distinct processes that were carried out by proliferative and invasive phenotypes of tumor cells, respectively. Two subpopulations from human neuroblastoma cell line were isolated: highly invasive (HI) cells and low-invasive (LI) cells. HI and LI cells had different proliferative rate and metastatic ability in vitro and in vivo. In addition, they had distinct activated signal pathways and sensitivities to chemotherapy drugs. Affymetrix microarray and quantitative reverse transcriptase–polymerase chain reaction revealed that visinin-like protein-1 (VSNL-1) mRNA in HI cells was significantly higher than that in LI cells. We also observed that VSNL-1 was over-expressed in tumor specimens from patients with distant organ metastases compared with those without metastases. Furthermore, the invasive and proliferative phenotypes of neuroblastoma cells could be exchanged by regulation of VSNL-1 expression in vitro and in vivo. Up-regulation of VSNL-1 potentiated the anoikis-resistant ability of neuroblastoma cell. The expression of anoikis inhibitor TrkB, intracellular adhesion molecule 1, major histocompatibility complex class I, CD44 and CD44v6 was associated with VSNL-1 level. These results suggested that distinct roles of proliferative and invasive phenotypes contributed to neuroblastoma progression and strongly demonstrated that VSNL-1 played a very important role in neuroblastoma metastasis. [ABSTRACT FROM AUTHOR]

The P53 tumor suppressor pathway plays an important role in cancer development. The auto-regulatory feedback mechanism of the P53 and MDM2 expression is critical in keeping proper tumor suppressor function of this pathway. This study examined the effect of P53 Arg72Pro variants on transactivation of polymorphic MDM2 promoter (T309G) and their associations with risk of developing gastric cardia adenocarcinoma (GCA) in a Chinese population. Luciferase assays consistently showed a significantly higher activity of the MDM2 309G promoter compared with the MDM2 309T promoter. In cells co-transfected with variant P53 cDNAs, P53-72Pro displayed a significantly higher ability to activate the MDM2 promoter than P53-72Arg. Genotype analyses in 500 GCA patients and 1000 controls showed that significantly increased risk for developing GCA was associated with the MDM2 309G and the P53 72Pro allele compared with the MDM2 309T and the P53 72Arg allele in an allele dose-dependent manner. A joint effect between the MDM2 and P53 polymorphisms in intensifying GCA risk was detected, with the odds ratio (OR) for the presence of both MDM2 390GG and P53 72Pro/Pro genotypes being 5.05 [95% confidence interval (CI), 2.50–10.20]. These results suggest that the P53 72Pro and MDM2 309G polymorphisms contribute to the risk of developing GCA. [ABSTRACT FROM AUTHOR]

Presents a response to a letter to the editor on gene polymorphisms.