Single-nucleotide polymorphisms in the RB1 gene and association with breast cancer in the British population

A substantial proportion of the familial risk of breast cancer may be attributable to genetic variants each contributing a small effect. pRb controls the cell cycle and polymorphisms within it are candidates for such low penetrance susceptibility alleles, since the gene has been implicated in several human tumours, particularly breast cancer. The purpose of this study was to determine whether common variants in the RB1 gene are associated with breast cancer risk. We assessed 15 tagging single-nucleotide polymorphisms (SNPs) using a case-control study design (n< or = 4474 cases and n < or = 4560 controls). A difference in genotype frequencies was found between cases and controls for rs2854344 in intron 17 (P-trend = 0.007) and rs198580 in intron 19 (P-trend = 0.018). Carrying the minor allele of these SNPs appears to confer a protective effect on breast cancer risk (odd ratio (OR) = 0.86 (0.76-0.96) for rs2854344 and OR = 0.80 (0.66-0.96) for rs198580). However, after adjusting for multiple testing these associations were borderline with an adjusted P-trend = 0.068 for the most significant SNP (rs2854344). The RB1 gene is not known to contain any coding SNPs with allele frequencies > or = 5% but several intronic variants are in perfect linkage disequilibrium with the associated SNPs. Replication studies are needed to confirm the associations with breast cancer.     

核苷酸切除修复通路基因多态性与肺癌易感性研究

目的研究显示核苷酸切除修复通路在去除吸烟引起的DNA损伤中发挥着重要的作用,旨在探讨核苷酸切除修复通路单核苷酸多态性与吸烟相关性肺癌易感性的关系。方法选取1010例肺癌患者和1011例正常对照。采用基于通路的候选基因选点策略,从核苷酸切除修复通路相关的8个核心基因中筛选出40个标签SNPs进行检测和分析。结果单个位点分析发现6个SNPs（ERCC1 2个,DDB2 2个,ERCC4／XPF 1个,XPC 1个）与肺癌的易感性相关。进一步采用Logistic回归模型,调整年龄、性别、吸烟史和肿瘤家族史后,仍有3个SNPs（ERCC1 rs3212948,DDB2 rs830083,ERCC4 rs3136038）与肺癌易感性存在统计学关联。等位基因联合分析结果进一步表明肺癌的发病风险随着风险等位基因个数的增加而增加,尤其是ERCC1,ERCC2,ERCC3,ERCC5,XPA和XPC。结论本研究结果提示核苷酸切除修复通路基因多态性可能与中国汉族人群的肺癌个体易感性有关,值得进一步进行功能学探讨及大样本人群验证.     

Genetic variation in TP53 and risk of breast cancer in a population-based case control study

Whereas germ line missense mutations in the tumor suppressor gene TP53 are associated with a marked predisposition to breast cancer, single-nucleotide polymorphisms (SNPs) may play a more modest role in breast cancer susceptibility. We examined genetic variation in TP53 in relation to breast cancer risk among women aged 20-74 years in a population-based case-control study in Wisconsin, Massachusetts and New Hampshire. Analyses were conducted separately for in situ (176 cases/581 controls) and invasive (1,490 cases/1,291 controls) breast cancer. Oral mucosal DNA samples were genotyped for the codon 72 polymorphism in exon 4 (rs1,042,522), seven intronic SNPs and three SNPs residing in the 3' untranslated region (UTR). Logistic regression was used to obtain age- and state-adjusted odds ratios for individual SNPs. Haplotypes were reconstructed using PHASE software, and the overall association with breast cancer risk was assessed using a global score test. None of the 11 individual SNPs or eight common haplotypes were significantly related to breast carcinoma in situ risk. Among all women, two linked SNPs (D' = 0.99, r(2) = 0.95) on intron 7 (rs12,951,053, rs12,947,788) were associated with modest increases in invasive breast cancer risk; however, associations were only significant for heterozygous carriers. The data suggested that additional variants in the 3' UTR (rs9,894,946), and in two correlated SNPs (D' = 0.94, r(2) = 0.81) in introns 6 (rs1,625,895) and 4 (rs2,909,430), were associated with reduced invasive breast cancer risk among women aged 50 and younger only (P(interaction) < 0.03). These results indicate that common variation in the TP53 gene could modify the risk of invasive breast cancer.     

Single nucleotide polymorphism analyses of the human proliferating cell nuclear antigen (pCNA) and flap endonuclease (FEN1) genes

The products of proliferating cell nuclear antigen (PCNA) and flap endonuclease (FEN1) genes are multifunctional proteins that are involved in DNA replication and damage repair. Yeast models suggest association of mutant forms of PCNA and FEN1 with genomic instability. In our study, we have determined the single nucleotide polymorphisms in human PCNA and FEN1 genes. We sequenced the coding region and adjacent noncoding region of both the PCNA and FEN1 genes in 120 alleles (60 individuals). In the PCNA gene, we detected 9 sequence variants with Hardy-Weinberg allele frequency ranging from 0.008 to 0.088. No polymorphism was detected in the FEN1 gene. The sequence variants in the PCNA gene included 7 intronic single nucleotide polymorphisms (SNP) and 2 synonymous exonic SNPs. All the intronic SNPs were located in introns 1 and 4, which contain several regulatory elements involved in the control of PCNA gene expression. Six of the 7 intronic SNPs showed complete linkage disequilibrium. We confirmed this allelic linkage disequilibrium by allele-specific PCR sequencing. We genotyped 117 additional individuals belonging to 3 population subgroups using the PCR-RFLP method. Finally, to see if the detected polymorphisms are associated with any cancer type, we genotyped cases with melanomas (37 cases), breast cancers (118 cases) and lung cancers (100 cases). We did not find statistical difference in frequency of polymorphism in any cancer type compared with healthy controls, although in breast cancer the frequency was low. Our results suggest that the coding regions of the PCNA and FEN1 genes are highly conserved when compared with other DNA repair genes. The potential of some of the detected intronic polymorphisms to effect regulation of the PCNA gene expression remains to be determined.     

Effect of Xeroderma Pigmentosum Complementation Group FPolymorphisms on Gastric Cancer Risk and Associations withH.pylori Infection

We conducted a hospital case-control study by genotyping four potential functional single nucleotidepolymorphisms (SNPs) to assess the association of Xeroderma pigmentosum complementation group F (XPF)with gastric cancer susceptibility, and role of XPF polymorphisms in combination with H.pylori infection in riskdefinition. A total of 331 patients with gastric cancer and 355 controls were collected. Four SNPs of XPF, rs180067,rs1799801, rs2276466 and rs744154, were genotyped by Taqman real-time PCR method with a 7900 HT sequencedetector system. The gastric cancer patients were more likely to have smoking habit, a family history of cancerand H.pylori infection. We did not find any significant difference in the genotype distributions of XPF rs180067,rs1799801, rs2276466 and rs744154 between cases and controls. However, multivariate logistic analysis showeda non-significant decreased risk in patients carrying rs180067 G allele, rs1799801 T allele or rs2276466 T allelegenotypes. A non-significant increased risk of gastric cancer was found in individuals carrying the rs744154 GGgenotype. Stratification by H.pylori infection and smoking was not significantly different in polymorphisms ofXPF rs180067, rs1799801, rs2276466 and rs744154. The four XPF SNPs did not show significant interaction withH.pylori infection and smoking status (P for interaction was 0.35 and 0.18, respectively). Our study indicatedthat polymorphisms in rs180067, rs1799801, rs2276466 and rs744154 may affect the risk of gastric cancer butfurther large sample size studies are needed to validate any association.     

Nucleotide excision repair genes and risk of lung cancer among San Francisco Bay Area Latinos and African Americans

Few studies on the association between nucleotide excision repair (NER) variants and lung cancer risk have included Latinos and African Americans. We examine variants in 6 NER genes (ERCC2, ERCC4, ERCC5, LIG1, RAD23B and XPC) in association with primary lung cancer risk among 113 Latino and 255 African American subjects newly diagnosed with primary lung cancer from 1998 to 2003 in the San Francisco Bay Area and 579 healthy controls (299 Latinos and 280 African Americans). Individual single nucleotide polymorphism and haplotype analyses, multifactor dimensionality reduction (MDR) and principal components analysis (PCA) were performed to assess the association between 6 genes in the NER pathway and lung cancer risk. Among Latinos, ERCC2 haplotype CGA (rs238406, rs11878644, rs6966) was associated with reduced lung cancer risk [odds ratio (OR) of 0.65 and 95% confidence interval (CI): 0.44-0.97], especially among nonsmokers (OR = 0.29; 95% CI: 0.12-0.67). From MDR analysis, in Latinos, smoking and 3 SNPs (ERCC2 rs171140, ERCC5 rs17655 and LIG1 rs20581) together had a prediction accuracy of 67.4% (p = 0.001) for lung cancer. Among African Americans, His/His genotype of ERCC5 His1104Asp (rs17655) was associated with increased lung cancer risk (OR = 1.78; 95% CI: 1.09-2.91), and LIG1 haplotype GGGAA (rs20581, rs156641, rs3730931, rs20579 and rs439132) was associated with reduced lung cancer risk (OR = 0.61; 95% CI: 0.42-0.88). Our study suggests different elements of the NER pathway may be important in the different ethnic groups resulting either from different linkage relationship, genetic backgrounds and/or exposure histories.     

Genetic variants of 6q25 and breast cancer susceptibility: a two-stage fine mapping study in a Chinese population

A recent genome-wide association study identified a novel single nucleotide polymorphism (SNP), rs2046210, in the 6q25 region as a breast cancer susceptibility locus in Chinese and subsequently replicated in a multicenter study. Further fine-mapping of this region may help identify the potential causative SNPs of breast cancer. We employed a block-based fine mapping analysis to investigate the tagging SNPs in a 41 kb block with the marker-SNP rs2046210 in the 6q25 region, and also extended our study by including two potentially functional SNPs (rs2234693 and rs1801132) within the ESR1 gene by a two-stage case–control study with 1,792 breast cancer cases and 1,867 controls (878 cases and 900 controls in the testing set and 914 cases and 967 controls in the validation set). Significant associations with breast cancer risk were observed for rs1038304, rs6929137, rs2046210, and rs10484919 in the 41 kb block of the 6q25 region in the testing set after controlling multiple testing. Together with the validation set samples, these four SNPs were all significantly associated with increased risk of breast cancer (additive OR from 1.25 to 1.34, additive P from 4.84 × 10⁻⁶ to 7.17 × 10⁻⁹). After conditional regression and linkage disequilibrium analyses, rs6929137 and rs10484919 tend to be susceptible markers of breast cancer in this region and both of them were located at sites of histone modification according to the UCSC () genome database. Our results support that the 6q25 region is an important susceptibility region for breast cancer in Chinese women, and rs6929137 and rs10484919 are causative or marker SNPs for this region.     

Polymorphisms in oxidative stress-related genes and postmenopausal breast cancer risk

Breast cancer is the most frequent cancer type among women in western countries. In addition to established risk factors like hormone replacement therapy, oxidative stress may play a role in carcinogenesis through an unbalanced generation of reactive oxygen species that leads to genetic instability. The aim of this study is to assess the influence of common single nucleotide polymorphisms (SNPs) in candidate genes related to oxidative stress on postmenopausal breast cancer risk. We genotyped 109 polymorphisms (mainly tagging SNPs) in 22 candidate genes in 1,639 postmenopausal breast cancer cases and 1,967 controls (set 1) from the German population-based case-control study "MARIE". SNPs showing association in set 1 were tested in further 863 cases and 2,863 controls from MARIE (set 2) using a joint analysis strategy. Six polymorphisms evaluated in the combined set showed significantly modified breast cancer risk per allele in the joint analysis, including SNPs in CYBA (encoding a subunit of the NADPH oxidase: rs3794624), MT2A (metallothionein 2A: rs1580833), TXN (thioredoxin: rs2301241), and in TXN2 (thioredoxin 2: rs2267337, rs2281082, rs4821494). Associations with the CYBA rs3794624 (OR per allele: 0.93, 95% CI 0.87-0.99) and TXN rs2301241 variants (OR per allele: 1.05, 95% CI 1.00-1.10) were confirmed in the summary risk estimate analysis using up to three additional studies. We found some evidence for association of polymorphisms in genes of the thioredoxin system, CYBA, and MT2A with postmenopausal breast cancer risk. Summary evidence including independent datasets indicated moderate effects in CYBA and TXN that warrant confirmation in large independent studies.     

Genetic variants at chromosome 9p21, 10p15 and 10q22 and breast cancer susceptibility in a Chinese population

A recent genome-wide association study (GWAS) has identified a new subset of breast cancer susceptibility loci on chromosomes 9, 10, and 11 in populations of European descent. However, because of the genetic heterogeneity, the role of these loci in non-European descent populations is still unclear. To evaluate the relationships between genetic variants in these regions identified by GWAS and breast cancer risk in Chinese women, we genotyped four common SNPs at 9p21(rs1011970 and rs10757278), 10p15 (rs2380205), and 10q22 (rs1250009) in a two-stage case-control study with a total of 1792 breast cancer cases and 1,867 controls. We found that rs1250009 at 10q22 was consistently associated with risk of breast cancer in stage 1 and stage 2, with a per-allele OR of 1.13 (95% CI 1.02-1.25) after two stages combined (P = 0.023). However, no significant associations were observed between the other three SNPs and breast cancer risk. Our results suggest that the genetic variants at 10q22 may play an important role in breast cancer development in Chinese women, and rs1250009 may be a candidate marker for breast cancer susceptibility.     

Functional intronic ERCC1 polymorphism from regulomeDB can predict survival in lung cancer after surgery

We searched for potential regulatory single nucleotide polymorphisms (SNPs) in excision repair cross-complementing group 1 (ERCC1) using RegulomeDB, a database integrating information from the Encyclopedia of DNA Elements (ENCODE) project, and investigated their association with survival after surgery in non-small cell lung cancer (NSCLC). Among 364 SNPs found within ERCC1 region using RegulomeDB, four top priority SNPs (rs2298881C>A, rs1049739A>G, rs10415949A>G and rs6509214G>T) were selected for this study. The four SNPs were investigated in 316 patients. A replication study was performed (n = 579). Of the four SNPs analyzed in the discovery set, rs2298881C>A and rs6509214G>T were significantly associated with survival outcomes. The association was consistently observed only for rs2298881C>A in the validation cohort. In combined analysis, rs2298881C>A was significantly associated with worse overall survival and disease-free survival (P = 0.0002 and 0.02, respectively). A decreased reporter gene expression for rs2298881 A allele was observed compared with C allele by luciferase assay (P = 0.02). ERCC1 rs2298881C>A, an intronic SNP, is the first genetic polymorphism with functional evidence of regulating its expression, and the SNP is associated with prognosis of NSCLC. Our result supports the role of RegulomeDB as a comprehensive source of prioritized candidate SNPs for genetic association studies.     

Evaluation of genetic variation in the double-strand break repair pathway and bladder cancer risk

The double-strand break DNA repair (DSBR) pathway is implicated in maintaining genomic stability and therefore could affect bladder cancer risk. Here we present data evaluating 39 single-nucleotide polymorphisms (SNPs) in seven candidate genes whose products are involved in DNA break sensing (NBS1, BRCA1 interacting genes BRIP1 and ZNF350), non-homologous end-joining (NHEJ) DNA repair (XRCC4) and homologous recombination (HR) repair (RAD51, XRCC2 and XRCC3). SNPs for RAD51 and XRCC2 covered most of the common variation. Associations with bladder cancer risk were evaluated in 1,150 newly diagnosed cases of urinary bladder transitional cell carcinomas and 1,149 controls conducted in Spain during 1997-2001. We found that the genetic variants evaluated significantly contributed to bladder cancer risk (global likelihood ratio test P = 0.01). Subjects with the ZNF350 R501S (rs2,278,415) variant allele showed significantly reduced risk compared with common homozygote variants, odds ratio (OR) [95% confidence interval (95% CI)]: 0.76 (0.62-0.93) per variant allele. Carriers of a putative functional SNP in intron 7 of XRCC4 (rs1,805,377) had significantly increased bladder cancer risk compared with common homozygotes: 1.33 (1.08-1.64) per variant allele. Lastly, XRCC2 homozygote variants for three promoter SNPs (rs10,234,749, rs6,464,268, rs3,218,373) and one non-synonymous SNP (rs3,218,536, R188H) were associated with reduced bladder cancer risk (ORs ranging from 0.36 to 0.50 compared with common homozygotes). Meta-analysis for XRCC3 T241M (rs861,539) had a significant small increase in risk among homozygote variants: OR (95% CI) = 1.17 (1.00-1.36). Results from this study provide evidence for associations between variants in genes in the DSBR pathway and bladder cancers risk that warrant replication in other study populations.     

A multistage association study identifies a breast cancer genetic locus at NCOA7

Estrogen metabolism and growth factor signaling pathway genes play key roles in breast cancer development. We evaluated associations between breast cancer and tagging single-nucleotide polymorphisms (SNP) of 107 candidate genes of these pathways using single allele- and haplotype-based tests. We first sought concordance of associations between two study populations: the Nashville Breast Cohort (NBC; 510 cases, 988 controls), and the Cancer Genetic Markers of Susceptibility (CGEMS) breast cancer study (1,145 cases, 1,142 controls). Findings across the two study populations were concordant at tagging SNPs of six genes, and at previously published SNPs of FGFR2. We sought further replication of results for EGFR, NCOA7, and FGFR2 in the independent Collaborative Breast Cancer Study (CBCS; 1,552 cases, 1,185 controls). Associations at NCOA7 and FGFR2 replicated across all three studies. The association at NCOA7 on 6q22.32, detected by a haplotype spanning the initial protein-coding exon (5'-rs9375411, rs11967627, rs549438, rs529858, rs490361, rs17708107-3'), has not been previously reported. The haplotype had a significant inverse association with breast cancer in each study [OR(Het): 0.69 (NBC), 0.76 (CGEMS), 0.79 (CBCS)], and a meta-analysis OR(Het) of 0.75 (95% CI, 0.65-0.87, P = 1.4 × 10(-4)) in the combined study populations. The haplotype frequency was 0.07 among cases, and 0.09 among controls; homozygotes were infrequent and each OR(Hom) was not significant. NCOA7 encodes a nuclear receptor coactivator that interacts with estrogen receptor α to modulate its activity. These observations provide consistent evidence that genetic variants at the NCOA7 locus may confer a reduced risk of breast cancer.     

Mutation analysis of RAD51L1 (RAD51B/REC2) in multiple-case, non-BRCA1/2 breast cancer families

Although a significant proportion of familial aggregation of breast cancer remains unexplained, many of the currently known breast cancer susceptibility genes, including BRCA1, BRCA2 and TP53, play a role in maintaining genome integrity by engaging in DNA repair. RAD51L1 is one of the five RAD51 paralogs involved in homologous recombination (HR) repair of DNA double-strand breaks (DSBs); it also interacts directly with p53. Deleterious mutations have been found in one RAD51 paralog, RAD51C (RAD51L2), in non-BRCA1/2 breast and ovarian cancer families, which suggests that all five paralogs are strong candidate breast cancer susceptibility genes. A genome-wide association study (GWAS) has already identified a single nucleotide polymorphism (SNP) deep within intron 10 of RAD51L1 as a risk locus for breast cancer. Based on its biological functions and association with RAD51C, there is reason to suggest that RAD51L1 (RAD51B/REC2) may also contain high risk mutations in the gene that give rise to multiple-case breast cancer families. In order to investigate this hypothesis, we have used high resolution melt (HRM) analysis to screen RAD51L1 for germline mutations in 188 non-BRCA1/2 multiple-case breast cancer families and 190 controls. We identified a total of seven variants: one synonymous, three intronic, and three previously identified SNPs, but no truncating or nonsense changes. Therefore, our results suggest that RAD51L1 is unlikely to represent a high-penetrance breast cancer susceptibility gene.     

A candidate CpG SNP approach identifies a breast cancer associated ESR1-SNP

Altered DNA methylation is often seen in malignant cells, potentially contributing to carcinogenesis by suppressing gene expression. We hypothesized that heritable methylation potential might be a risk factor for breast cancer and evaluated possible association with breast cancer for single nucleotide polymorphisms (SNPs) either involving CpG sequences in extended 5'-regulatory regions of candidate genes (ESR1, ESR2, PGR, and SHBG) or CpG and missense coding SNPs in genes involved in methylation (MBD1, MECP2, DNMT1, MGMT, MTHFR, MTR, MTRR, MTHFD1, MTHFD2, BHMT, DCTD, and SLC19A1). Genome-wide searches for genetic risk factors for breast cancers have in general not investigated these SNPs, because of low minor allele frequency or weak haplotype associations. Genotyping was performed using Mass spectrometry-Maldi-Tof in a screening panel of 538 cases and 1,067 controls. Potential association to breast cancer was identified for 15 SNPs and one of these SNPs (rs7766585 in ESR1) was found to associate strongly with breast cancer, OR 1.30 (95% CI 1.17-1.45; p-value 2.1 × 10(-6)), when tested in a verification panel consisting of 3,211 unique breast cancer cases and 4,223 unique controls from five European biobank cohorts. In conclusion, a candidate gene search strategy focusing on methylation-related SNPs did identify a SNP that associated with breast cancer at high significance.     

Polymorphisms in angiogenesis-related genes and prostate cancer.

BACKGROUND: Angiogenesis is required for development and progression of prostate cancer. Potentially functional single nucleotide polymorphisms (SNP) in genes important in prostate angiogenesis (VEGF, HIF1A, and NOS3) have previously been associated with risk or severity of prostate cancer. METHODS: Prostate cancer cases (n = 1,425) and controls (n = 1,453) were selected from the Cancer Prevention Study II Nutrition Cohort. We examined associations between 58 SNPs in nine angiogenesis-related candidate genes (EGF, LTA, HIF1A, HIF1AN, MMP2, MMP9, NOS2A, NOS3, VEGF) and risk of overall and advanced prostate cancer. Unconditional logistic regression was used to estimate odds ratios, adjusted for matching factors. RESULTS: Our results did not replicate previously observed associations with SNPs in VEGF, HIF1A, or NOS3, nor did we observe associations with SNPs in EGF, LTA, HIF1AN, MMP9, or NOS2A. In the MMP2 gene, three intronic SNPs, all in linkage disequilibrium, were associated with overall and advanced prostate cancer (for overall prostate cancer, P(trend) = 0.01 for rs1477017, P(trend) = 0.01 for rs17301608, P(trend) = 0.02 for rs11639960). However, two of these SNPs (rs17301608 and rs11639960) were examined and were not associated with prostate cancer in a recent genome-wide association study using prostate cancer cases and controls from the Prostate, Lung, Colorectal, and Ovary study cohort. Furthermore, when we pooled our results for these two SNPs with those from the Prostate, Lung, Colorectal, and Ovary cohort; neither SNP was associated with prostate cancer. CONCLUSION: None of the SNPs examined seem likely to be importantly associated with risk of overall or advanced prostate cancer.     

Nucleotide excision repair polymorphisms may modify ionizing radiation-related breast cancer risk in US radiologic technologists

Exposure to ionizing radiation has been consistently associated with increased risk of female breast cancer. Although the majority of DNA damage caused by ionizing radiation is corrected by the base-excision repair pathway, certain types of multiple-base damage can only be repaired through the nucleotide excision repair pathway. In a nested case-control study of breast cancer in US radiologic technologists exposed to low levels of ionizing radiation (858 cases, 1,083 controls), we examined whether risk of breast cancer conferred by radiation was modified by nucleotide excision gene polymorphisms ERCC2 (XPD) rs13181, ERCC4 (XPF) rs1800067 and rs1800124, ERCC5 (XPG) rs1047769 and rs17655; and ERCC6 rs2228526. Of the 6 ERCC variants examined, only ERCC5 rs17655 showed a borderline main effect association with breast cancer risk (OR(GC) = 1.1, OR(CC) = 1.3; p-trend = 0.08), with some indication that individuals carrying the C allele variant were more susceptible to the effects of occupational radiation (EOR/Gy(GG) = 1.0, 95% CI = <0, 6.0; EOR/Gy(GC/CC) = 5.9, 95% CI = 0.9, 14.4; p(het) = 0.10). ERCC2 rs13181, although not associated with breast cancer risk overall, statistically significantly modified the effect of occupational radiation dose on risk of breast cancer (EOR/Gy(AA) = 9.1, 95% CI = 2.1-21.3; EOR/Gy(AC/CC) = 0.6, 95% CI = <0, 4.6; p(het) = 0.01). These results suggest that common variants in nucleotide excision repair genes may modify the association between occupational radiation exposure and breast cancer risk.     

TNRC9和FGFR2基因多态性与湖北地区汉族人群乳腺癌患病风险研究

目的:研究探讨TNRC9基因rs3803662和FGFR2基因rs17102287单核苷酸多态性(SNP)及两SNP连锁与湖北地区汉族妇女乳腺癌易感性的关系.方法:抽取汉族510例乳腺癌患者和550例健康妇女外周血,分离淋巴细胞,抽提基因组DNA,检测TNRC9 rs3803662和FGFR2 rs17102287 的基因多态性,计算基因型和等位基因频率,研究各基因型以及基因SNP连锁之间对乳腺癌风险的影响.结果:TNRC9基因SNP位点rs3803662的C/C、C/T和T/T基因型频率在病例组和对照组分别为13.0％、46.4％、40.6％和7.3％、52.1％、40.6％,其基因型频率相比差异有统计学意义,x2=9.40,P=0.043.而等位基因频率两组相比差异均无统计学意义;FGFR2基因SNP位点rs17102287的C/C、C/T和T/T基因型频率在病例组和对照组中差异无统计学意义;等位基因频率两组相比差异无统计学意义.两基因连锁分析D'=0.087,r2=0.085,没有明显连锁不平衡现.结论:TNRC9基因rs3803662多态性与汉族妇女乳腺癌易感性有关,FGFR2基因rs17102287多态性及其与TNRC9基因rs3803662单倍体连锁与湖北地区汉族人群妇女乳腺癌易感性无相关性.     

ERCC6/CSB gene polymorphisms and lung cancer risk

Nucleotide excision repair (NER) enzymes are critical for the removal of bulky DNA adducts caused by environmental carcinogens such as smoking. Of them, Cockayne syndrome complementation group B (CSB), coded by ERCC6, recruits NER repair factors to the DNA damage site and plays an important role in the repair process. Genetic variants of ERCC6 may alter the regulation of DNA repair and therefore were hypothesized to be associated with altered risk of smoking-related lung cancer. To test this hypothesis, we genotyped eight tagging single nucleotide polymorphisms (tSNPs) and three potentially functional SNPs of ERCC6 in 500 incident lung cancer cases and 517 controls in a Chinese population. Single locus analyses showed that none of the single SNP alone had the significant main affect on the risk of lung cancer. However, the combined variant genotypes of the four loci with P(trend) approaching to 0.10 (rs2228526, rs4253160, rs12571445 and rs3793784) were associated with a significantly increased lung cancer risk (adjusted OR 1.35, 95% CI, 1.04-1.75 among subjects carrying three or more variant alleles), indicating that multiple loci in ERCC6 may jointly contribute to the susceptibility of lung cancer. These findings, if validated, may contribute to identify at-risk subjects in the general population for smoking-related lung cancer.     

Evaluation of Genetic Variations in miRNA-Binding Sites of BRCA1 and BRCA2 Genes as Risk Factors for the Development of Early-Onset and/or Familial Breast Cancer

Although genetic markers identifying women at an increased risk of developing breast cancer exist, themajority of inherited risk factors remain elusive. Mutations in the BRCA1/BRCA2 gene confer a substantialincrease in breast cancer risk, yet routine clinical genetic screening is limited to the coding regions and intronexonboundaries, precluding the identification of mutations in noncoding and untranslated regions. Because 3’untranslated region (3’UTR) polymorphisms disrupting microRNA (miRNA) binding can be functional and canact as genetic markers of cancer risk, we aimed to determine genetic variation in the 3’UTR of BRCA1/BRCA2in familial and early-onset breast cancer patients with and without mutations in the coding regions of BRCA1/BRCA2 and to identify specific 3’UTR variants that may be risk factors for cancer development. The 3’UTRs ofthe BRCA1 and BRCA2 genes were screened by heteroduplex analysis and DNA sequencing in 100 patients from46 BRCA1/2 families, 54 non-BRCA1/2 families, and 47 geographically matched controls. Two polymorphismswere identified. SNPs c.*1287C>T (rs12516) (BRCA1) and c.*105A>C (rs15869) (BRCA2) were identified in27% and 24% of patients, respectively. These 2 variants were also identified in controls with no family historyof cancer (23.4% and 23.4%, respectively). In comparison to variations in the 3’UTR region of the BRCA1/2genes and the BRCA1/2 mutational status in patients, there was a statistically significant relationship betweenthe BRCA1 gene polymorphism c.*1287C>T (rs12516) and BRCA1 mutations (p=0.035) by Fisher’s Exact Test.SNP c.*1287C>T (rs12516) of the BRCA1 gene may have potential use as a genetic marker of an increased risk ofdeveloping breast cancer and likely represents a non-coding sequence variation in BRCA1 that impacts BRCA1function and leads to increased early-onset and/or familial breast cancer risk in the Turkish population.