Polymorphisms in the Transforming Growth Factor Beta 1 Pathway in Relation to Colorectal Cancer Progression

Transforming growth factor beta 1 (TGFB1) acts as a growth inhibitor of normal colonic epithelial cells, however, as a tumor promoter of colorectal cancer (CRC) cells. To explore the association between genetic polymorphisms in the TGFB1 pathway and CRC susceptibility and clinical outcome, we carried out a case-control study on a Swedish population of 308 CRC cases and 585 age- and gender-matched controls. The cases were sampled prospectively and had up to 16 years follow-up, making the study material particularly suitable for survival analysis. On the basis of their reported or predicted functional effect, nine single-nucleotide polymorphisms (TGFB1: Leu10Pro; TGFBR1: 9A/6A and IVS7G+24A; FURIN: C-229T; THBS1: T+42C; LTBP1L: C-256G; LTBP4: T-893G and Thr750Ala; BAMB1: T-779A) were selected for genotyping. We evaluated the associations between genotypes and CRC and Dukes' stage. Survival probabilities were compared between different subgroups. The observed statistically significant associations included a decreased CRC risk for TGFBR1 IVS7G+24A minor allele carriers (odds ratio (OR): 0.72, 95% confidence interval (CI): 0.53-0.97), less aggressive tumors with Dukes' stage A+B for carriers of LTBP4 Thr750Ala and BAMB1 T-779A minor alleles (OR: 0.58, 95%CI: 0.36-0.93 and OR: 0.51, 95%CI: 0.29-0.89, respectively) and worse survival for FURIN C-229T heterozygotes (hazard ratio: 1.63, 95%CI: 1.08-2.46). As this is the first study about the influence of the polymorphisms in the TGFBI pathway on CRC progression, further studies in large independent cohorts are warranted. (C) 2009 Wiley-Liss, Inc

Prognostic impact of polymorphisms in the MYBL2 interacting genes in breast cancer

MYBL2 is a transcription factor, which regulates the expression of genes involved in cancer progression. In this study, we investigated whether putative functional variants in genes regulating MYBL2 (E2F1, E2F3 and E2F4) or in genes, which are regulated by MYBL2 (BCL2, BIRC5, COL1A1, COL1A2, COL5A2, ERBB2, CLU, LIN9 and TOP2A) affect breast cancer (BC) susceptibility and clinical outcome. Twenty-eight SNPs were genotyped in a population-based series of 782 Swedish BC cases and 1,559 matched controls. BC-specific survival analysis of BIRC5 suggested that carriers of the minor allele of rs8073069 and rs1042489 have a worse survival compared with the major homozygotes (HR 2.46, 95% CI 1.39-4.36 and HR 1.81, 95% CI 1.01-3.25, respectively). The poor survival was observed especially in women with aggressive tumours. Multivariate analysis supported the role of rs8073069 as an independent prognostic marker. For BCL2, minor allele carriers of rs1564483 were more likely to have hormone receptor-positive tumours than the major homozygotes. Another SNP in BCL2, rs4987852, was associated with tumour stages II-IV and histologic grade 3. In CLU, the minor allele carriers of rs9331888 were more likely to have tumours with regional lymph node metastasis and stages II-IV than the major homozygotes. In conclusion, our study suggests a role of genetic variation in BIRC5, BCL2 and CLU as progression and prognostic markers for BC, supporting previous studies based on the expression of the genes

Functional germline variants in driver genes of breast cancer

Purpose: Germline mutations in tumour suppressor genes cause various cancers. These genes are also somatically mutated in sporadic tumours. We hypothesized that there may also be cancer-related germline variants in the genes commonly mutated in sporadic breast tumours. Methods: After excluding the well-characterized breast cancer (BC) genes, we screened 15 novel genes consistently classified as BC driver genes in next-generation sequencing approaches for single nucleotide polymorphisms (SNPs). Altogether 40 SNPs located in the core promoter, 5′- and 3′-UTR or which were nonsynonymous SNPs were genotyped in 782 Swedish incident BC cases and 1,559 matched controls. After statistical analyses, further evaluations related to functional prediction and signatures of selection were performed. Results: TBX3 was associated with BC risk (rs2242442: OR = 0.76, 95% CI 0.64–0.92, dominant model) and with less aggressive tumour characteristics. An association with BC survival and aggressive tumour characteristics was detected for the genes ATR (rs2227928: HR = 1.63; 95% CI 1.00–2.64, dominant model), RUNX1 (rs17227210: HR = 3.50, 95% CI 1.42–8.61, recessive model) and TTN (rs2303838: HR = 2.36; 95% CI 1.04–5.39; rs2042996: HR = 2.28; 95% CI 1.19–4.37, recessive model). According to the experimental ENCODE data all these SNPs themselves or SNPs in high linkage disequilibrium with them (r2 ≥ 0.80) were located in regulatory regions. RUNX1 and TTN showed also several signatures of positive selection. Conclusion: The study gave evidence that germline variants in BC driver genes may have impact on BC risk and/or survival. Future studies could discover further germline variants in known or so far unknown driver genes which contribute to cancer development

Polymorphisms in telomere-associated genes, breast cancer susceptibility and prognosis

Telomeres are essential structures for maintaining chromosomal stability and their length has been reported to correlate with cancer risk and clinical outcome. Single nucleotide polymorphisms (SNPs) in genes encoding telomere-associated proteins could affect telomere length and chromosomal stability by influencing gene expression or protein configuration in the telomeres. Here, we report the results of the first association study on genetic variation in telomere-associated genes and their effect on telomere length, breast cancer (BC) susceptibility and prognosis. We genotyped 14 potentially functional and most informative SNPs in nine telomere-associated genes (TERT, TEP1, TERF1, TERF2, TERF21p, ACD, POT1, TNKS and TNKS2) in 782 incident BC cases and 1559 matched controls. Relative telomere length (RTL) varied statistically significantly between the genotypes of the SNPs rs446977 (TEP1, p = 0.04), rs938886 (TEP1, p = 0.04) and rs6990097 (TNKS, p = 0.04). However, none of them was associated with BC susceptibility and only rs6990097 correlated with regional lymph node metastasis (odds ratio (OR) 1.38, 95% confidence interval (CI) 1.08-1.77). The strongest association with BC susceptibility was observed for rs3785074 (TERF2, OR 0.51, 95% CI 0.31-0.83) and rs10509637 (TNKS2, OR 1.33, 9S% CI 1.08-1.62). Haplotype and diplotype analysis confirmed the association of the TNKS2 gene with BC susceptibility. rs3785074 (TERF2) was additionally associated with histologic grade (OR 1.44, 95% CI 1.08-1.92) and negative oestrogen receptor status (OR 2.93, 95% CI 1.13-7.58). None of the SNPs showed a significant correlation with survival of the breast cancer patients. With these results, none of the SNPs represents any valuable prognostic marker for BC. (C) 2009 Elsevier Ltd. All rights reserved

Genetic variation in genes encoding for polymerase zeta subunits associates with breast cancer risk, tumour characteristics and survival

Chromosomal instability is a known hallmark of many cancers. DNA polymerases represent a group of enzymes that are involved in the mechanism of chromosomal instability as they have a central function in DNA metabolism. We hypothesized that genetic variation in the polymerase genes may affect gene expression or protein configuration and by that cancer risk and clinical outcome. We selected four genes encoding for the catalytic subunits of the polymerases beta, delta, theta and zeta (POLB, POLD1, POLQ and REV3L, respectively) and two associated proteins (MAD2L2 and REV1) because of their previously reported association with chromosomal instability and/or tumorigenesis. We selected potentially functional and most informative tagging single nucleotide polymorphisms (SNPs) for genotyping in a population-based series of 783 Swedish breast cancer (BC) cases and 1562 controls. SNPs that showed a significant association in the Swedish population were additionally genotyped in a Polish population consisting of 506 familial/early onset BC cases and 568 controls. SNPs in all three polymerase zeta subunit genes associated either with BC risk or prognosis. Two SNPs in REV3L and one SNP in MAD2L2 associated with BC risk: rs462779 (multiplicative model: OR 0.79, 95% CI 0.68-0.92), rs3204953 (dominant model: OR 1.28, 95% CI 1.05-1.56) and rs2233004 (recessive model: OR 0.49, 95% CI 0.28-0.86). Homozygous carriers of the minor allele C of the third SNP in REV3L, rs11153292, had significantly worse survival compared to the TT genotype carriers (HR 2.93, 95% CI 1.34-6.44). Minor allele carriers of two REV1 SNPs (rs6761391 and rs3792142) had significantly more often large tumours and tumours with high histological grade and stage. No association was observed for SNPs in POLB, POLQ and POLD1. Altogether, our data suggest a significant role of genetic variation in the polymerase zeta subunit genes regarding the development and progression of BC

Genetic variation in ALCAM and other chromosomal instability genes in breast cancer survival

Chromosomal instability is a hallmark of many cancers and it has a potential to predict clinical outcome of a cancer patient. We hypothesized that genes whose expression status differs between chromosomal stable and unstable breast tumors represent target genes for the identification of genetic variants predicting breast cancer (BC) risk, disease progression, and survival. We used a published list of 38 genes associated with chromosomal instability as a basis for searching potentially functional and informative tagging single nucleotide polymorphisms (SNPs). As a result, 33 SNPs in 16 genes were genotyped in a population-based series of 783 Swedish BC cases. Two SNPs in the ALCAM gene associated with BC-specific survival. For rs1044243, the HR was 4.35 (95% CI 1.34-14.18), and for rs1157, the HR was 3.42 (95% CI 1.32-8.83) for the homozygous carriers of the minor alleles. For the minor allele carriers of CCL18 SNP rs14304, we observed a significant association with aggressive tumor characteristics: large tumor size (OR 1.53, 95% CI 1.10-2.14), positive lymph node metastasis (OR 1.75, 95% CI 1.02-3.00), and high stage (OR 1.37, 95% CI 1.02-1.85). In a Polish population consisting of 506 familial/early onset BC cases, no association with event-free survival for the ALCAM SNPs nor any association with tumor characteristics for the CCL18 SNP were observed, suggesting either a chance finding in the Swedish population or population-based or etiological differences between sporadic and familial/early onset BC

Systematic Pathway Enrichment Analysis of a Genome-Wide Association Study on Breast Cancer Survival Reveals an Influence of Genes Involved in Cell Adhesion and Calcium Signaling on the Patients' Clinical Outcome

Genome-wide association studies (GWASs) may help to understand the effects of genetic polymorphisms on breast cancer (BC) progression and survival. However, they give only a focused view, which cannot capture the tremendous complexity of this disease. Therefore, we investigated data from a previously conducted GWAS on BC survival for enriched pathways by different enrichment analysis tools using the two main annotation databases Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The goal was to identify the functional categories (GO terms and KEGG pathways) that are consistently overrepresented in a statistically significant way in the list of genes generated from the single nucleotide polymorphism (SNP) data. The SNPs with allelic p-value cut-offs 0.005 and 0.01 were annotated to the genes by excluding or including a 20 kb up-and down-stream sequence of the genes and analyzed by six different tools. We identified eleven consistently enriched categories, the most significant ones relating to cell adhesion and calcium ion binding. Moreover, we investigated the similarity between our GWAS and the enrichment analyses of twelve published gene expression signatures for breast cancer prognosis. Five of them were commonly used and commercially available, five were based on different aspects of metastasis formation and two were developed from meta-analyses of published prognostic signatures. This comparison revealed similarities between our GWAS data and the general and the specific brain metastasis gene signatures as well as the Oncotype DX signature. As metastasis formation is a strong indicator of a patient's prognosis, this result reflects the survival aspect of the conducted GWAS and supports cell adhesion and calcium signaling as important pathways in cancer progression

Circulating Vitamin D and Risk of Epithelial Ovarian Cancer

We conducted a nested case-control study within two prospective cohorts, the New York University Women's Health Study and the Northern Sweden Health and Disease Study, to examine the association between prediagnostic circulating levels of 25-hydroxy vitamin D (25(OH)D) and the risk of subsequent invasive epithelial ovarian cancer (EOC). The 25(OH)D levels were measured in serum or plasma from 170 incident cases of EOC and 373 matched controls. Overall, circulating 25(OH)D levels were not associated with the risk of EOC in combined cohort analysis: adjusted OR for the top tertile versus the reference tertile, 1.09 (95% CI, 0.59–2.01). In addition, there was no evidence of an interaction effect between VDR SNP genotype or haplotype and circulating 25(OH)D levels in relation to ovarian cancer risk, although more complex gene-environment interactions may exist

Inbreeding and homozygosity in breast cancer survival

Genome-wide association studies (GWASs) help to understand the effects of single nucleotide polymorphisms (SNPs) on breast cancer (BC) progression and survival. We performed multiple analyses on data from a previously conducted GWAS for the influence of individual SNPs, runs of homozygosity (ROHs) and inbreeding on BC survival. (I.) The association of individual SNPs indicated no differences in the proportions of homozygous individuals among short-time survivors (STSs) and long-time survivors (LTSs). (II.) The analysis revealed differences among the populations for the number of ROHs per person and the total and average length of ROHs per person and among LTSs and STSs for the number of ROHs per person. (III.) Common ROHs at particular genomic positions were nominally more frequent among LTSs than in STSs. Common ROHs showed significant evidence for natural selection (iHS, Tajima's D, Fay-Wu's H). Most regions could be linked to genes related to BC progression or treatment. (IV.) Results were supported by a higher level of inbreeding among LTSs. Our results showed that an increased level of homozygosity may result in a preference of individuals during BC treatment. Although common ROHs were short, variants within ROHs might favor survival of BC and may function in a recessive manner