1. |
- Shi, Hong, et al.
(author)
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Single nucleotide polymorphisms in the 20q13 amplicon genes in relation to breast cancer risk and clinical outcome
- 2011
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In: Breast Cancer Research and Treatment. - New York : Springer-Verlag New York. - 0167-6806 .- 1573-7217. ; 130:3, s. 905-916
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Journal article (peer-reviewed)abstract
- The 20q13 region is frequently amplified/overexpressed in breast tumours. However, the nature of this amplification/overexpression is unknown. Here, we investigated genetic variation in five 20q13 amplicon genes (MYBL2, AURKA, ZNF217, STK4 and PTPN1) and its impact on breast cancer (BC) susceptibility and clinical outcome. As a novel finding, four polymorphisms in STK4 (rs6017452, rs7271519) and AURKA (rs2273535, rs8173) associated with steroid hormone receptor status both in a Swedish population-based cohort of 783 BC cases and in a Polish familial/early onset cohort of 506 BC cases. In the joint analysis, the minor allele carriers of rs6017452 had more often hormone receptor positive tumours (OR 0.57, 95% CI 0.40-0.81), while homozygotes for the minor allele of rs7271519, rs2273535 and rs8173 had more often hormone receptor negative tumours (2.26, 1.30-3.39; 2.39, 1.14-5.01; 2.39, 1.19-4.80, respectively) than homozygotes for the common allele. BC-specific survival analysis of AURKA suggested that the Swedish carriers of the minor allele of rs16979877, rs2273535 and rs8173 might have a worse survival compared with the major homozygotes. The survival probabilities associated with the AURKA genotypes depended on the tumour phenotype. In the Swedish case-control study, associations with BC susceptibility were observed in a dominant model for three MYBL2 promoter polymorphisms (rs619289, P = 0.02; rs826943, P = 0.03 and rs826944, P = 0.02), two AURKA promoter polymorphisms (rs6064389, P = 0.04 and rs16979877, P = 0.02) and one 3'UTR polymorphism in ZNF217 (rs1056948, P = 0.01). In conclusion, our data confirmed the impact of the previously identified susceptibility locus and provided preliminary evidence for novel susceptibility variants in BC. We provided evidence for the first time that genetic variants at 20q13 may affect hormone receptor status in breast tumours and influence tumour aggressiveness and survival of the patients. Future studies are needed to confirm the prognostic value of our findings in the clinic.
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2. |
- Varadi, Verena, et al.
(author)
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A functional promoter polymorphism in the TERT gene does not affect inherited susceptibility to breast cancer
- 2009
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In: Cancer Genetics and Cytogenetics. - : Elsevier. - 0165-4608 .- 1873-4456. ; 190:2, s. 71-74
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Journal article (peer-reviewed)abstract
- Telomere dysfunction is a key mechanism in cancer development. The human telomerase reverse transcriptase (TERT) is the rate-limiting catalytic subunit of the telomerase enzyme, which is necessary for the maintenance of telomere DNA length, chromosomal stability, and cellular immortality. In our attempt to identify functional polymorphisms in the TERT gene and their effect on breast cancer risk, we sequenced the promoter of the gene and identified three single nucleotide polymorphisms (SNPs) with a frequency of at least 10%. One of these SNPs, rs2853669 (-244 T > C), has been shown to affect telomerase activity and telomere length. Recently, this SNP has been suggested to affect familial breast cancer risk. In our case-control study using two large breast cancer sample series, including one with 841 cases with inherited susceptibility to breast cancer, we did not find any association with familial or sporadic breast cancer risk. This well-powered study excludes an effect of the functional -244 T > C SNP and two other correlated SNPs on breast cancer risk.
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3. |
- Varadi, Verena, et al.
(author)
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Genetic variation in ALCAM and other chromosomal instability genes in breast cancer survival
- 2012
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In: Breast Cancer Research and Treatment. - : Springer Science and Business Media LLC. - 0167-6806 .- 1573-7217. ; 131:1, s. 311-319
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Journal article (peer-reviewed)abstract
- 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.
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4. |
- Varadi, Verena, et al.
(author)
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Genetic variation in genes encoding for polymerase zeta subunits associates with breast cancer risk, tumour characteristics and survival
- 2011
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In: Breast Cancer Research and Treatment. - : Springer Science and Business Media LLC. - 1573-7217 .- 0167-6806. ; 129:1, s. 235-245
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Journal article (peer-reviewed)abstract
- 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.
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