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The chromosomal passenger complex (CPC) plays a pivotal role in the regulation of cell division. Therefore, inherited CPC variability could influence tumor development. The present candidate gene approach investigates the relationship between single nucleotide polymorphisms (SNPs) in genes encoding key CPC components and breast cancer risk. Fifteen SNPs in four CPC genes (INCENP, AURKB, BIRC5 and CDCA8) were genotyped in 88 911 European women from 39 case-control studies of the Breast Cancer Association Consortium. Possible associations were investigated in fixed-effects meta-analyses. The synonymous SNP rs1675126 in exon 7 of INCENP was associated with overall breast cancer risk [per A allele odds ratio (OR) 0.95, 95% confidence interval (CI) 0.92-0.98, P = 0.007] and particularly with estrogen receptor (ER)-negative breast tumors (per A allele OR 0.89, 95% CI 0.83-0.95, P = 0.0005). SNPs not directly genotyped were imputed based on 1000 Genomes. The SNPs rs1047739 in the 3' untranslated region and rs144045115 downstream of INCENP showed the strongest association signals for overall (per T allele OR 1.03, 95% CI 1.00-1.06, P = 0.0009) and ER-negative breast cancer risk (per A allele OR 1.06, 95% CI 1.02-1.10, P = 0.0002). Two genotyped SNPs in BIRC5 were associated with familial breast cancer risk (top SNP rs2071214: per G allele OR 1.12, 95% CI 1.04-1.21, P = 0.002). The data suggest that INCENP in the CPC pathway contributes to ER-negative breast cancer susceptibility in the European population. In spite of a modest contribution of CPC-inherited variants to the total burden of sporadic and familial breast cancer, their potential as novel targets for breast cancer treatment should be further investigated.

Breast cancer (BC) is the leading cancer in women worldwide. Changes in DNA methylation in peripheral blood could be associated with malignant diseases. Making use of screening results by llumina 27K Methylation Assay, we validated demethylation of five CpG sites of S100P gene in blood cell DNA of BC patients by three independent retrospective studies with subjects from different centers (Validation I: 235 familial BC case and 206 controls, odds ratio per -1% methylation > 1.03, and P < 6.00 × 10-8 for all five CpG sites; Validation II: 189 sporadic BC case and 189 controls, odds ratio per -1% methylation > 1.03, P < 8.0 × 10-5 for four CpG sites; Validation III: 156 sporadic BC case and 151 controls, odds ratio per -1% methylation > 1.03, P < 6.0 × 10-4 for four CpG sites). In addition, the blood-based S100P methylation pattern was similar among BC patients with differential clinical characteristics regardless of stage, receptor status and menopause status. The observed BC-associated decreased S100P methylation in blood mainly originates from the leucocytes subpopulations but not B cells. The methylation levels of most S100P CpG sites were inversely correlated with the expression of S100P in leucocytes (P < 1.2 × 10-4) and in tissue (P < 1.1 × 10-4). This study reveals significant association between blood-based decreased S100P methylation and BC, and provides another proof for the application of altered DNA methylation signatures from blood cells as potential markers for the detection of BC, especially for the early stage., (© The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Colorectal cancer (CRC) is one of the most common cancer worldwide. However, a large number of genetic risk factors involved in CRC have not been understood. Copy number variations (CNVs) might partly contribute to the 'missing heritability' of CRC. An increased overall burden of CNV has been identified in several complex diseases, whereas the association between the overall CNV burden and CRC risk is largely unknown. We performed a genome-wide investigation of CNVs on genomic DNA from 384 familial CRC cases and 1285 healthy controls by the Affymetrix 6.0 array. An increase of overall CNV burden was observed in familial CRC patients compared with healthy controls, especially for CNVs larger than 50kb (case/control ratio = 1.66, P = 0.025). In addition, we discovered for the first time a novel structural variation at 12p12.3 and determined the breakpoints by strategic PCR and sequencing. This 12p12.3 structural variation was found in four of 2862 CRC cases but not in 6243 healthy controls (P = 0.0098). RERGL gene (RERG/RAS-like), the only gene influenced by the 12p12.3 structural variation, sharing most of the conserved regions with its close family member RERG tumor suppressor gene (RAS-like, estrogen-regulated, growth inhibitor), might be a novel CRC-related gene. In conclusion, this is the first study to reveal the contribution of the overall burden of CNVs to familial CRC risk and identify a novel rare structural variation at 12p12.3 containing RERGL gene to be associated with CRC.

MicroRNAs (miRNAs) negatively regulate expression of target transcripts by hybridization to complementary sites of their messenger RNA targets. Chen et al. have described several putative functional single nucleotide polymorphisms (SNPs) in miRNA target sites. Here, we selected 11 miRNA target site SNPs located in 3' untranslated regions of genes involved in cancer and breast cancer to analyze their impact on breast cancer risk using a large familial study population. Whereas no association was observed for 10 SNPs, a significant association was revealed for the variant affecting a miRNA target site in the estrogen receptor (ESR) 1. Age stratification showed that the association was stronger in premenopausal women [C versus T: odds ratio (OR) = 0.60, confidence interval (CI) = 0.41-0.89, P = 0.010]. Furthermore, the effect was stronger in high-risk familial cases (C versus T: OR = 0.42, CI = 0.25-0.71, P = 0.0009). Clinical studies have shown that elimination of ESR1 significantly reduces breast cancer risk. Thus, therapies that inhibit ESR1 are used for breast cancer treatment. According to in silico analysis, ESR1&#95;rs2747648 affects the binding capacity of miR-453, which is stronger when the C allele is present. In contrast, the T allele attenuates the binding of miR-453, which might lead to a reduced miRNA-mediated ESR1 repression, in consequence higher ESR1 protein levels and an increased breast cancer risk. Thus, the breast cancer protective effect observed for the C allele in premenopausal women is biologically reasonable. The analysis of large study populations in multicentre collaboration will be needed to verify the association and answer questions regarding the possible impact of this variant on therapeutic and clinical outcome.

Ultraconserved elements (UCEs) are segments of >200 bp length showing absolute sequence identity between orthologous regions of human, rat and mouse genomes. The selection factors acting on these UCEs are still unknown. Recent studies have shown that UCEs function as long-range enhancers of flanking genes or are involved in splicing when overlapping with exons. The depletion of UCEs among copy number variation as well as the significant under-representation of single-nucleotide polymorphisms (SNPs) within UCEs have also revealed their evolutional and functional importance indicating their potential impact on disease, such as cancer. In the present study, we investigated the influence of six SNPs within UCEs on familial breast cancer risk. Two out of six SNPs showed an association with familial breast cancer risk. Whereas rs9572903 showed only a borderline significant association, the frequency of the rare [G] allele of rs2056116 was higher in cases than in controls indicating an increased familial breast cancer risk ([G] versus [A]: odds ratio (OR) = 1.18, 95% confidence interval (CI) 1.06-1.30, P = 0.0020; [GG] versus [AA]: OR = 1.41, 95% CI 1.15-1.74, P = 0.0011). Interestingly, comparing with the older age group, the ORs were increased in woman younger than 50 years of age ([G] versus [A]: OR = 1.27, 95% CI 1.11-1.45, P = 0.0005; [GG] versus [AA]: OR = 1.60, 95% CI 1.22-2.10, P = 0.0007) pointing to an age- or hormone-related effect. This is the first study indicating that SNPs in UCEs might be associated with cancer risk.

Copy number variants (CNVs), insertions, deletions and duplications, contribute considerably to human genetic variation and disease development. A recent study has characterized 100 CNVs including a deletion in the mitochondrial tumor suppressor gene 1 (MTUS1) lacking the coding exon 4. MTUS1 maps to chromosome 8p, a region frequently deleted and associated with disease progression in human cancers, including breast cancer (BC). To investigate the effect of the MTUS1 CNV on familial BC risk, we analyzed 593 BC patients and 732 control individuals using a case-control study design. We found a significant association of the deletion variant with a decreased risk for both familial and high-risk familial BC (odds ratio (OR) = 0.58, 95% confidence interval (CI) = 0.37-0.90, P = 0.01 and OR = 0.41, 95% CI = 0.23-0.74, P = 0.003), supporting its role in human cancer. To our knowledge, the present study is the first to determine the impact of a CNV in a tumor suppressor gene on cancer risk.