Tumor susceptibility and prognosis of breast cancer associated with the G870A polymorphism of CCND1

The association of single nucleotide polymorphisms (SNPs) with breast density and breast cancer survival: the Malmö Diet and Cancer Study

Background

Genetic factors are important in determining breast density, and heritable factors account for 60% of the variation. Certain single nucleotide polymorphisms (SNPs) are associated with density and risk of breast cancer but the association with prognosis is not clear.

Purpose

To investigate associations between selected SNPs and breast cancer survival in the Malmö Diet and Cancer Study (MDCS).

Material and Methods

A total of 724 unrelated women with breast cancer and registered radiological and pathological data were identified in MDCS 1991–2007, with genotyping available for 672 women. Associations among 15 SNPs, density, and breast cancer-specific survival were analyzed using logistic/Cox regression, adjusted for factors affecting density and survival. Variants significantly associated with either density or survival were validated in a large independent breast cancer cohort (LIBRO-1).

Results

Minor homozygotes of SNPs rs9383589, CCDC170 and rs6557161, ESR1 were associated with high breast density (adjusted odds ratio [AOR] 8.97, 95% confidence interval [CI] 1.35–59.57; AOR 2.08, 95% CI 1.19–3.65, respectively) and poorer breast cancer survival (adjusted hazard ratio [HR_adj] 6.46, 95% CI 1.95–21.39; HR_adj 2.30, 95% CI 1.33–3.96, respectively) compared to major homozygotes. For SNP rs3757318, ESR1, minor homozygotes (HR_adj 7.46, 95% CI 2.28–24.45) were associated with poorer survival. We confirmed that rs6557161, ESR1 was significantly associated with both density and survival in the LIBRO-1 study.

Conclusion

These findings support a shared genetic basis for density and breast cancer survival. The SNP significantly associated with both density and survival in both cohorts may be of interest in future research investigating polygenic risk scores for breast cancer risk and screening stratification purposes.

AA genotype of cyclin D1 G870A polymorphism increases breast cancer risk: Findings of a case-control study and meta-analysis

BACKGROUND

Cyclin D1 (CCND1) polymorphisms, a regulator of the cell cycle progress from G1 to the S phase, may lead to uncontrolled cell proliferation and lack of apoptosis. G870A, a common single-nucleotide polymorphism in CCND1 influences breast cancer risk. However, the association between G870A polymorphism and breast cancer risk is ambiguous so far.

MATERIALS AND METHODS

In this case-control study, we analyzed the role of G870A polymorphism with breast cancer risk in Indian women. A meta-analysis of 18 studies was also performed to elucidate this association by increasing statistical power.

RESULTS

In our case-control study, significant risk association of the CCND1 G870A AA genotype with breast cancer in total cohort (odds ratio [OR], 2.98; 95% confidence interval [CI], 1.64-5.42; P value, 4.96e-04) and premenopausal women (OR, 3.31; 95% CI, 1.54-7.08; P value, .003) was found. The results of the meta-analysis showed that AA genotype of the CCND1 G870A polymorphism significantly increases breast cancer risk in total pooled data (AA vs GG+GA: OR = 1.20; 95% CI = 1.03 to 1.39; P value, 0.016*) and Caucasian (AA vs GG+GA: OR = 1.22; 95% CI = 0.99 to 1.51; P value, .056*) but not in Asian population. Further, a significant protective association with breast cancer was also found in the GA vs AA comparison model in pooled data (OR = 0.73; 95% CI = 0.58 to 0.92; P value, .007*) as well as in Caucasian subgroup (OR = 0.62; 95% CI = 0.49 to 0.94; P value, .022*).

CONCLUSION

CCND1 G870A AA genotype was found associated with breast cancer risk. Future association studies considering the environmental impact on gene expression are required to validate/explore this association.

Effect of Polymorphisms in XRCC1, CCND1 and GSTM1 and Tobacco Exposure as Risk Modifier for Oral Leukoplakia

Analysis of gene-environment interactions may help to define the risk of oral leukoplakia. We hypothesized that an individual's susceptibility to leukoplakia is dependent on interactions between polymorphic genotypes at susceptible loci and tobacco exposure. To test this hypothesis, the relationship between tobacco use and polymorphisms in 3 genes that might contribute to variance in individuals′ susceptibility to the risk of leukoplakia was determined. In this case-control study, polymorphic genotypes in XRCC1 (399Gln), a DNA repair gene involved in removing DNA adducts, CCND1 (G870A), a key component of cell cycle regulation, and GSTM1 (null genotype), a xenobiotic-metabolizing enzyme involved in the metabolism of tobacco carcinogens, were analyzed in 100 oral leukoplakia patients and age- and gender-matched controls by PCR using genomic DNA isolated from blood. The GSTM1 null genotype was associated with a 1.6-fold increased risk of developing leukoplakia. The risk conferred by the CCND1 GA+AA variant was 2.4-fold that of the GG genotype. Importantly, among non-users of tobacco, the XRCC1 (GA+AA) variant emerged as the most significant determinant of an individual's susceptibility to leukoplakia (OR=3.5). In GSTM1 null individuals, tobacco consumption increased the risk of leukoplakia 21.3 fold. Similarly, XRCC1 A allele carriers and CCND1 A allele carriers who consumed tobacco were at a significantly high risk of developing leukoplakia (OR=11.8 and 14.9, respectively). Our study provides evidence that tobacco use in individuals harboring these polymorphic genotypes elevates the risk of oral leukoplakia and warrants further studies on gene-environment interactions to define the risk of malignant transformation of leukoplakia.

Association of CCND1 Gene c.870G>A Polymorphism with Breast Cancer Risk: A Case-ControlStudy and a Meta-Analysis

Cyclin D1 (CCND1) plays an essential role in regulating the progress of the cell cycle from G1 to S phase. There is a common c.870G>A polymorphism in the CCND1 gene. The aim of this study was to investigate the association of CCND1 gene c.870G>A polymorphism with breast cancer risk in a case-control study, which followed by a meta-analysis and an in silico analysis. Three hundred and thirty-five subjects composed of 174 women with breast cancer and 161 healthy controls were included in the case-control study. CCND1 gene c.870G>A genotyping was performed by PCR-RFLP. Meta-analysis was done for 14 studies composed of 7281 cases and 6820 controls. Some bioinformatics tools were applied to investigate the effects of c.870G>A on the mRNA splicing and structure. Our data obtained from case-control study revealed that GA genotype (OR: 1.89, 95%CI: 1.12-3.17, p = 0.017), AA genotype (OR: 1.95, 95%CI: 1.08-3.53, p = 0.027), and A allele (OR: 1.44, 95%CI: 1.06-1.95, p = 0.019) were significantly associated with breast cancer risk. The results of meta-analysis showed a significant association between CCND1 c.870G>A polymorphism and breast cancer risk, especially in Caucasian population. In silico analysis revealed that c.870G>A transition affect CCND1 mRNA splicing and secondary structure.

Association between cyclin D1 G870A polymorphism and hepatocellular carcinoma risk: a meta-analysis

Background

Cyclin D1 (CCND1) G870A polymorphism may be associated with hepatocellular carcinoma (HCC) risk, but the results of previous studies were inconsistent. Available evidence was meta-analyzed to assess their potential association.

Methods

Databases PubMed, EMBASE, Cochrane Library, Web of Science, Chinese Biomedical Literature database, China National Knowledge Infrastructure, and Google Scholar were systematically searched. Meta-analyses were performed to investigate the association of G870A polymorphism with HCC risk by calculating odds ratios (ORs) and 95% confidence intervals (CIs) from the data of relevant case–control studies.

Results

Results of this meta-analysis of six case–control studies involving 1,030 cases and 1,683 controls indicate that G870A polymorphism was not associated with HCC risk in any of the five genetic models tested (recessive model: AA vs GG + AG: OR =1.38, 95% CI =0.95–2.00, P=0.09; dominant model: AG + AA vs GG: OR =1.38, 95% CI =0.87–2.20, P=0.17; homozygous model: AA vs GG: OR =1.60, 95% CI =0.87–2.94, P=0.13; heterozygous model: AG vs GG: OR =1.24, 95% CI =0.86–1.79, P=0.25; allelic model: A vs G: OR =1.30, 95% CI =0.95–1.80, P=0.10). Subgroup analyses according to ethnicity showing marginally significant association between this single nucleotide polymorphism and HCC risk indicate that G870A may be significantly associated with HCC risk in Caucasian populations (recessive model: AA vs GG + AG: OR =2.34, 95% CI =1.60–3.42, P<0.0001; dominant model: AG + AA vs GG: OR =2.44, 95% CI =1.19–4.97, P=0.01; homozygous model: AA vs GG: OR =3.42, 95% CI =1.80–6.50, P=0.0002; allelic model: A vs G: OR =2.06, 95% CI =1.31–3.24, P=0.002), but not in Asian populations.

Conclusion

Available evidence suggests that no significant association between G870A polymorphism and HCC risk was found in either total populations or Asian populations. However, significant association was found in Caucasian populations. These results should be verified and extended in further detailed and well-designed studies involving larger, multiethnic samples.

Polymorphism at 19q13.41 Predicts Breast Cancer Survival Specifically after Endocrine Therapy

PURPOSE

Although most patients with estrogen receptor (ER)-positive breast cancer benefit from endocrine therapies, a significant proportion do not. Our aim was to identify inherited genetic variations that might predict survival among patients receiving adjuvant endocrine therapies.

EXPERIMENTAL DESIGN

We performed a meta-analysis of two genome-wide studies; Helsinki Breast Cancer Study, 805 patients, with 240 receiving endocrine therapy and Prospective study of Outcomes in Sporadic versus Hereditary breast cancer, 536 patients, with 155 endocrine therapy patients, evaluating 486,478 single-nucleotide polymorphisms (SNP). The top four associations from the endocrine treatment subgroup were further investigated in two independent datasets totaling 5,011 patients, with 3,485 receiving endocrine therapy.

RESULTS

A meta-analysis identified a common SNP rs8113308, mapped to 19q13.41, associating with reduced survival among endocrine-treated patients [hazard ratio (HR), 1.69; 95% confidence interval (CI), 1.37-2.07; P = 6.34 × 10(-7)] and improved survival among ER-negative patients, with a similar trend in ER-positive cases not receiving endocrine therapy. In a multivariate analysis adjusted for conventional prognostic factors, we found a significant interaction between the rs8113308 and endocrine treatment, indicating a predictive, treatment-specific effect of the SNP rs8113308 on breast cancer survival, with the per-allele HR for interaction 2.16 (95% CI, 1.30-3.60; Pinteraction = 0.003) and HR = 7.77 (95% CI, 0.93-64.71) for the homozygous genotype carriers. A biologic rationale is suggested by in silico functional analyses.

CONCLUSIONS

Our findings suggest carrying the rs8113308 rare allele may identify patients who will not benefit from adjuvant endocrine treatment.

Association of breast cancer risk loci with breast cancer survival

The survival of breast cancer patients is largely influenced by tumor characteristics, such as TNM stage, tumor grade and hormone receptor status. However, there is growing evidence that inherited genetic variation might affect the disease prognosis and response to treatment. Several lines of evidence suggest that alleles influencing breast cancer risk might also be associated with breast cancer survival. We examined the associations between 35 breast cancer susceptibility loci and the disease over-all survival (OS) in 10,255 breast cancer patients from the National Cancer Institute Breast and Prostate Cancer Cohort Consortium (BPC3) of which 1,379 died, including 754 of breast cancer. We also conducted a meta-analysis of almost 35,000 patients and 5,000 deaths, combining results from BPC3 and the Breast Cancer Association Consortium (BCAC) and performed in silico analyses of SNPs with significant associations. In BPC3, the C allele of LSP1-rs3817198 was significantly associated with improved OS (HRper-allele =0.70; 95% CI: 0.58-0.85; ptrend  = 2.84 × 10(-4) ; HRheterozygotes  = 0.71; 95% CI: 0.55-0.92; HRhomozygotes  = 0.48; 95% CI: 0.31-0.76; p2DF  = 1.45 × 10(-3) ). In silico, the C allele of LSP1-rs3817198 was predicted to increase expression of the tumor suppressor cyclin-dependent kinase inhibitor 1C (CDKN1C). In the meta-analysis, TNRC9-rs3803662 was significantly associated with increased death hazard (HRMETA =1.09; 95% CI: 1.04-1.15; ptrend  = 6.6 × 10(-4) ; HRheterozygotes  = 0.96 95% CI: 0.90-1.03; HRhomozygotes  = 1.21; 95% CI: 1.09-1.35; p2DF =1.25 × 10(-4) ). In conclusion, we show that there is little overlap between the breast cancer risk single nucleotide polymorphisms (SNPs) identified so far and the SNPs associated with breast cancer prognosis, with the possible exceptions of LSP1-rs3817198 and TNRC9-rs3803662.

Genetic association between cyclin D1 polymorphism and breast cancer susceptibility

Cyclin D1 polymorphism has been reported to be associated with risk of breast cancer, but the published studies have yielded controversial results. This study was undertaken to derive a precise risk estimate for the cyclin D1 polymorphism associated with breast cancer risk. We performed a search of EMBASE, PubMed, and Web of Science. In total, data from 18 publications were pooled and the association was assessed by odds ratios (ORs) with 95 % confidence intervals (CIs). This analysis showed that there was no obvious association between the cyclin D1 polymorphism and breast cancer risk in any of the analyzed genetic model. We found the same negative association in stratified analyses by ethnicity, source of controls, and sample size. Our meta-analysis provides an estimate that the presence of cyclin D1 polymorphism may not confer susceptibility to breast cancer.

The cyclin D1 (CCND1) G870A polymorphism and lung cancer susceptibility: a meta-analysis

Several studies have investigated the association between Cyclin D1 (CCND1) G870A genetic polymorphism and lung cancer susceptibility, but the results were inconclusive. The aim of this meta-analysis was to summarize available evidence for such a relationship. The reviewers made use of MEDLINE, EMBASE, and BIOSIS databases. The relevant data were independently extracted by two reviewers. The odds ratio (OR) with 95% confidence interval (CI) was selected as the principal outcome measure. The heterogeneity test, the publication bias test, and the sensitivity analysis were performed. Overall, a total of 10 case-control studies were included. Our meta-analysis indicated that CCND1 G870A genetic polymorphism was a risk factor for lung cancer under homozygote model (OR = 1.18; 95% CI = 1.02, 1.37), recessive model (OR = 1.21; 95% CI = 1.03, 1.41), and allele model (OR = 1.11; 95% CI = 1.02, 1.21). In the subgroup analysis by source of ethnicity, a statistical increase of lung cancer risk was found among Asian groups for allele model (OR = 1.11; 95% CI = 1.01-1.22). The present meta-analysis suggests that CCND1 G870A polymorphism may be a risk factor for lung cancer. Besides, allele A may contribute to increased lung cancer risk.

A common and functional gene variant in the vascular endothelial growth factor a predicts clinical outcome in early-stage breast cancer

Angiogenesis and cell cycle control play critical roles in breast cancer susceptibility and clinical outcome and are mainly controlled by vascular endothelial growth factor (VEGF) and cyclin-dependent kinases, respectively. Functional germline polymorphisms in these genes alter the function, thereby causing inter-individual differences in breast cancer risk and clinical outcome. In this study, we investigated the influence of the functional polymorphisms VEGF-A rs3025039 C > T and CCND1 rs9344 G > A on risk and clinical outcome in early-stage breast cancer. DNA of 539 female patients with histologically confirmed early-stage breast cancer and 804 control subjects was genotyped for these polymorphisms. Genotypes were tested for associations with breast cancer risk and clinical outcome. There was no significant association between the polymorphisms and breast cancer risk. However, the minor allele of VEGF-A rs3025039 C > T was significantly associated with decreased recurrence-free survival (HR 1.845; 95% confidence interval [CI] 1.035-3.290; P = 0.038) and remained significant in multivariate analysis (HR 1.880; 95% CI 1.020-3.465; P = 0.043). Patients carrying at least one A-allele in CCND1 rs9344 G > A showed a trend towards decreased recurrence-free survival in univariate analysis (HR 2.379; 95% CI 0.841-6.728; P = 0.068). This study provides evidence that the functional VEGF-A rs3025039 C > T polymorphism influences recurrence-free survival in early-stage breast cancer.

The role of genetic breast cancer susceptibility variants as prognostic factors

Recent genome-wide association studies identified 11 single nucleotide polymorphisms (SNPs) associated with breast cancer (BC) risk. We investigated these and 62 other SNPs for their prognostic relevance. Confirmed BC risk SNPs rs17468277 (CASP8), rs1982073 (TGFB1), rs2981582 (FGFR2), rs13281615 (8q24), rs3817198 (LSP1), rs889312 (MAP3K1), rs3803662 (TOX3), rs13387042 (2q35), rs4973768 (SLC4A7), rs6504950 (COX11) and rs10941679 (5p12) were genotyped for 25 853 BC patients with the available follow-up; 62 other SNPs, which have been suggested as BC risk SNPs by a GWAS or as candidate SNPs from individual studies, were genotyped for replication purposes in subsets of these patients. Cox proportional hazard models were used to test the association of these SNPs with overall survival (OS) and BC-specific survival (BCS). For the confirmed loci, we performed an accessory analysis of publicly available gene expression data and the prognosis in a different patient group. One of the 11 SNPs, rs3803662 (TOX3) and none of the 62 candidate/GWAS SNPs were associated with OS and/or BCS at P<0.01. The genotypic-specific survival for rs3803662 suggested a recessive mode of action [hazard ratio (HR) of rare homozygous carriers=1.21; 95% CI: 1.09-1.35, P=0.0002 and HR=1.29; 95% CI: 1.12-1.47, P=0.0003 for OS and BCS, respectively]. This association was seen similarly in all analyzed tumor subgroups defined by nodal status, tumor size, grade and estrogen receptor. Breast tumor expression of these genes was not associated with prognosis. With the exception of rs3803662 (TOX3), there was no evidence that any of the SNPs associated with BC susceptibility were associated with the BC survival. Survival may be influenced by a distinct set of germline variants from those influencing susceptibility.

Genetic variation of ESR1 and its co-activator PPARGC1B is synergistic in augmenting the risk of estrogen receptor-positive breast cancer

Introduction

Given the role of estrogen in breast carcinogenesis and the modification of estrogen receptor (ER) activity by its biochemical cofactors, we hypothesize that genetic variation within ER cofactor genes alters cellular response to estrogen exposure and consequently modifies the risk for ER-positive breast cancer.

Methods

We genotyped 790 tagging SNPs within 60 ER cofactor genes in 1,257 cases and 1,464 controls from Sweden and in 2,215 cases and 1,265 controls from Finland, and tested their associations with either ER-positive or ER-negative breast cancer.

Results

Seven SNPs showed consistent association with ER-positive breast cancer in the two independent samples, and six of them were located within PPARGC1B, encoding an ER co-activator, with the strongest association at rs741581 (odds ratio = 1.41, P = 4.84 × 10^-5) that survived Bonferroni correction for multiple testing in the combined ER-positive breast cancer sample (P_corrected = 0.03). Moreover, we also observed significant synergistic interaction (P_interaction = 0.008) between the genetic polymorphisms within PPARGC1B and ESR1 in ER-positive breast cancer. By contrast, no consistent association was observed in ER-negative breast cancer. Furthermore, we found that administration of estrogen in the MCF-7 cell line induced PPARGC1B expression and enhanced occupancies of ER and RNA polymerase II within the region of SNP association, suggesting the upregulation of PPARGC1B expression by ESR1 activation.

Conclusions

Our study revealed that DNA polymorphisms of PPARGC1B, coding a bona fide ER co-activator, are associated with ER-positive breast cancer risk. The feed-forward transcriptional regulatory loop between PPARGC1B and ESR1 further augments their protein interaction, which provides a plausible mechanistic explanation for the synergistic genetic interaction between PPARGC1B and ESR1 in ER-positive breast cancer. Our study also highlights that biochemically and genomically informed candidate gene studies can enhance the discovery of interactive disease susceptibility genes.

Cyclin D1 G870A polymorphism and breast cancer risk: a meta-analysis comprising 9,911 cases and 11,171 controls

Cyclin D1 represents a key molecule in the regulation of cell cycle. CCND1 G870A (rs603965) polymorphism has drawn considerable attention as the A allele may generate a variant splice product with possible oncogenic actions. A meta-analysis examining the association between CCND1 G870A polymorphism and breast cancer risk was performed. Separate analyses on Caucasian and Chinese populations were also implemented. Eligible articles were identified for the period up to July 2010. Pooled odds ratios (OR) were appropriately derived from fixed-effects or random-effects models. Sensitivity analysis excluding studies whose genotype frequencies in controls significantly deviated from Hardy-Weinberg Equilibrium (HWE) was performed. Nine case-control studies on Caucasians (7,304 cases and 8,149 controls) and four case-control studies on Chinese (2,607 cases and 3,022 controls) were eligible. At the overall analysis the A allele seemed to be associated with elevated breast cancer risk; the effect seemed to be confined to homozygous carriers (pooled OR = 1.091, 95% CI: 1.008-1.179, P = 0.030, fixed effects) as heterozygous carriers did not exhibit significantly elevated breast cancer risk. No statistically significant associations were demonstrated in Caucasians. On the other hand, Chinese AA carriers exhibited marginally elevated breast cancer risk (pooled OR = 1.144, 95% CI: 0.984-1.329, P = 0.080, fixed effects). Nevertheless, the controls in two out of the four Chinese studies deviated from HWE. In conclusion, this meta-analysis suggests that the A allele of the CCND1 G870A polymorphism may confer additional breast cancer risk when it comes to homozygosity and Chinese populations. The need for additional, methodologically sound studies on Chinese populations seems warranted.

Cyclin D1 splice variants: polymorphism, risk, and isoform-specific regulation in prostate cancer

PURPOSE

Alternative CCND1 splicing results in cyclin D1b, which has specialized, protumorigenic functions in prostate not shared by the cyclin D1a (full length) isoform. Here, the frequency, tumor relevance, and mechanisms controlling cyclin D1b were challenged.

EXPERIMENTAL DESIGN

First, relative expression of both cyclin D1 isoforms was determined in prostate adenocarcinomas. Second, relevance of the androgen axis was determined. Third, minigenes were created to interrogate the role of the G/A870 polymorphism (within the splice site), and findings were validated in primary tissue. Fourth, the effect of G/A870 on cancer risk was assessed in two large case-control studies.

RESULTS

Cyclin D1b is induced in tumors, and a significant subset expressed this isoform in the absence of detectable cyclin D1a. Accordingly, the isoforms showed noncorrelated expression patterns, and hormone status did not alter splicing. Whereas G/A870 was not independently predictive of cancer risk, A870 predisposed for transcript-b production in cells and in normal prostate. The influence of A870 on overall transcript-b levels was relieved in tumors, indicating that aberrations in tumorigenesis likely alter the influence of the polymorphism.

CONCLUSIONS

These studies reveal that cyclin D1b is specifically elevated in prostate tumorigenesis. Cyclin D1b expression patterns are distinct from that observed with cyclin D1a. The A870 allele predisposes for transcript-b production in a context-specific manner. Although A870 does not independently predict cancer risk, tumor cells can bypass the influence of the polymorphism. These findings have major implications for the analyses of D-cyclin function in the prostate and provide the foundation for future studies directed at identifying potential modifiers of the G/A870 polymorphism.

Cyclin D1b protein expression in breast cancer is independent of cyclin D1a and associated with poor disease outcome

Aberrant expression of cyclin D1 protein is a common feature of breast cancer. However, the CCND1 gene encodes two gene products, cyclin D1a and cyclin D1b, which have discrete mechanisms of regulation and impact on cell behavior. A polymorphism at nucleotide 870 in the CCND1 gene, rs603965, influences the relative production of the encoded proteins and can impart increased risk for tumor development. Here, the impact of both the G/A870 polymorphism and cyclin D1b protein production on breast cancer risk, disease phenotype and patient outcome was analysed. In a large multiethnic case-control study, the G/A870 polymorphism conferred no significant risk for breast cancer overall or by stage or estrogen receptor (ER) status. However, the cyclin D1b protein was found to be upregulated in breast cancer, independent of cyclin D1a levels, and exhibited heterogeneous levels in breast cancer specimens. High cyclin D1a expression inversely correlated with the Ki67 proliferation marker and was not associated with clinical outcome. In contrast, elevated cyclin D1b expression was independently associated with adverse outcomes, including recurrence, distant metastasis and decreased survival. Interestingly, cyclin D1b was particularly associated with poor outcome in the context of ER-negative breast cancer. Thus, specific cyclin D1 isoforms are associated with discrete forms of breast cancer and high cyclin D1b protein levels hold prognostic potential.

Screening and association testing of common coding variation in steroid hormone receptor co-activator and co-repressor genes in relation to breast cancer risk: the Multiethnic Cohort

Background

Only a limited number of studies have performed comprehensive investigations of coding variation in relation to breast cancer risk. Given the established role of estrogens in breast cancer, we hypothesized that coding variation in steroid receptor coactivator and corepressor genes may alter inter-individual response to estrogen and serve as markers of breast cancer risk.

Methods

We sequenced the coding exons of 17 genes (EP300, CCND1, NME1, NCOA1, NCOA2, NCOA3, SMARCA4, SMARCA2, CARM1, FOXA1, MPG, NCOR1, NCOR2, CALCOCO1, PRMT1, PPARBP and CREBBP) suggested to influence transcriptional activation by steroid hormone receptors in a multiethnic panel of women with advanced breast cancer (n = 95): African Americans, Latinos, Japanese, Native Hawaiians and European Americans. Association testing of validated coding variants was conducted in a breast cancer case-control study (1,612 invasive cases and 1,961 controls) nested in the Multiethnic Cohort. We used logistic regression to estimate odds ratios for allelic effects in ethnic-pooled analyses as well as in subgroups defined by disease stage and steroid hormone receptor status. We also investigated effect modification by established breast cancer risk factors that are associated with steroid hormone exposure.

Results

We identified 45 coding variants with frequencies ≥ 1% in any one ethnic group (43 non-synonymous variants). We observed nominally significant positive associations with two coding variants in ethnic-pooled analyses (NCOR2: His52Arg, OR = 1.79; 95% CI, 1.05–3.05; CALCOCO1: Arg12His, OR = 2.29; 95% CI, 1.00–5.26). A small number of variants were associated with risk in disease subgroup analyses and we observed no strong evidence of effect modification by breast cancer risk factors. Based on the large number of statistical tests conducted in this study, the nominally significant associations that we observed may be due to chance, and will need to be confirmed in other studies.

Conclusion

Our findings suggest that common coding variation in these candidate genes do not make a substantial contribution to breast cancer risk in the general population. Cataloging and testing of coding variants in coactivator and corepressor genes should continue and may serve as a valuable resource for investigations of other hormone-related phenotypes, such as inter-individual response to hormonal therapies used for cancer treatment and prevention.

Cyclin D1 Pro241Pro (CCND1-G870A) polymorphism is associated with increased cancer risk in human populations: a meta-analysis

The G870A polymorphism in the CCND1 gene may influence cancer risk. However, data from published studies with individual low statistical power have been controversial. To evaluate whether combined evidence shows an association between this polymorphism and cancer, we considered all available studies in a meta-analysis. Sixty studies were combined representing data for 18,411 cases and 22,209 controls. In our meta-analysis, we investigated overall sample and two ethnic populations (Caucasians and Asians) as well as nine cancer subtypes. Individuals who are homozygous for A allele (AA) were found to be associated with significantly increased cancer risk in overall sample [odds ratio (OR), 1.23; 95% confidence interval (95% CI), 1.13-1.33; P <or= 0.0001], Caucasians (OR, 1.16; 95% CI, 1.07-1.26; P=0.0002), and Asians (OR, 1.26; 95% CI, 1.14-1.39; P <or= 0.001). Among the nine cancer subtypes investigated, modestly significant risk (ORs, 1.08 to 1.51; P=0.02 to 0.04) was detected in breast, colorectal, head and neck, and other cancers. Highly significant and increased risk was found to be associated with genitourinary (OR, 1.51; 95% CI, 1.20-1.89; P=0.0004) and blood-related cancers (OR, 1.62; 95% CI, 1.28-2.05; P <or= 0.0001). Individuals who are heterozygous for AG were found to be at increased risk in overall, ethnic groups, as well as breast and colorectal cancers. Significant dominant effects seem to prevail in the majority of the categories investigated, where some recessive effects were also detected. Overall, the risk effects associated with this polymorphism were small; however, due its common occurrence, it affects a large portion of the human population (AA, 25%; AG, 50%). Although the independent small risk associated with CCND1-A870G polymorphism is not clinically useful, its interaction with other genetic variants and environmental factors has been shown to be associated with further increase in cancer risk (OR, 1.6-7.1). In conclusion, our study strongly supports the increased cancer risk associated with CCND1-A870G polymorphism in the human population.

Increased risk for second primary malignancies in women with breast cancer diagnosed at young age: a population-based study in Taiwan

Studies conducted in Western countries have reported excess risks for second primary malignancies after breast cancer. However, there is little documentation of ethnic differences in these excess risks. Asian women are characterized by younger age at diagnosis of breast cancer, but very few reports are available on the incidences and risks for second primary cancers in this region. Using population-based data from the Taiwan National Cancer Registry (TNCR) for the period 1979 to 2003, we quantified standardized incidence ratios and cumulative incidence of second cancers among 53,783 women with initial diagnoses of breast cancer. Age-specific incidences showed peaks among women in their 40s, and 1,085 cases (2.02%) developed nonbreast second primary cancers. The risk for second cancers differs significantly according to age at diagnosis of breast cancer. In comparison with women diagnosed when >or=50 years (standardized incidence ratio, 0.96; 95% confidence interval; 0.89-1.04), there were significantly greater risks for bone, corpus uterine, ovarian, thyroid, esophageal, kidney and lung cancers, nonmelanoma skin cancer, and leukemia or lymphoma in women diagnosed when <50 years (standardized incidence ratio, 1.43; 95% confidence interval, 1.29-1.58). The survival probabilities differed between breast cancer patients with and without second cancers (P<0.001). After diagnosis of the second cancer, the median survival time was only 2.87 years. In conclusion, we confirmed that young age at diagnosis of breast cancer predicted a subsequently increased risk for second malignancies, and the second cancers indeed worsen survivorship in patients who survived breast cancer.

The spliceosome as target for anticancer treatment

The spliceosome is a ribonucleoprotein complex involved in RNA splicing, that is, the removal of non-coding introns from precursor messenger RNA. (Alternative) Splicing events may play an essential role in tumourigenesis. The recent discovery that the spliceosome is a target for novel compounds with anticancer activity opens up new therapeutic avenues.