IGFBP3 A-202C polymorphism and breast cancer susceptibility: a meta-analysis involving 33,557 cases and 45,254 controls

Genetic architecture of mammographic density as a risk factor for breast cancer: a systematic review

BACKGROUND

Mammography Density (MD) is a potential risk marker that is influenced by genetic polymorphisms and can subsequently modulate the risk of breast cancer. This qualitative systematic review summarizes the genes and biological pathways involved in breast density and discusses the potential clinical implications in view of the genetic risk profile for breast density.

METHODS

The terms related to "Common genetic variations" and "Breast density" were searched in Scopus, PubMed, and Web of Science databases. Gene pathways analysis and assessment of protein interactions were also performed.

RESULTS

Eighty-six studies including 111 genes, reported a significant association between mammographic density in different populations. ESR1, IGF1, IGFBP3, and ZNF365 were the most prevalent genes. Moreover, estrogen metabolism, signal transduction, and prolactin signaling pathways were significantly related to the associated genes. Mammography density was an associated phenotype, and eight out of 111 genes, including COMT, CYP19A1, CYP1B1, ESR1, IGF1, IGFBP1, IGFBP3, and LSP1, were modifiers of this trait.

CONCLUSION

Genes involved in developmental processes and the evolution of secondary sexual traits play an important role in determining mammographic density. Due to the effect of breast tissue density on the risk of breast cancer, these genes may also be associated with breast cancer risk.

Prognostic value of IGFBP2 in various cancers: a systematic review and meta-analysis

BACKGROUND

The prognostic significance of insulin-like growth factor binding protein 2 (IGFBP2) expression has been explored in plenty of studies in human cancers. Because of the controversial results, the meta-analysis was carried out to evaluate the relevance of IGFBP2 expression with the prognosis in various tumors.

METHODS

The data searched from four databases (Pubmed, Embase, Cochrane library, and Web of science) was used to calculate pooled hazard ratios (HRs) in this meta-analysis. Subgroup analyses were stratified by ethnicity, cancer type, publication year, Newcastle-Ottawa Scale score, treatments, and populations.

RESULTS

Twenty-one studies containing 5560 patients finally met inclusion criteria. IGFBP2 expression was associated with lower overall survival (HR = 1.57, 95% CI = 1.31-1.88) and progression-free survival (HR = 1.18, 95% CI = 1.04-1.34) in cancer patients, but not with disease-free survival (HR = 1.50, 95% CI = 0.91-2.46) or recurrence-free survival (HR = 1.50, 95% CI = 0.93-2.40). The subgroup analyses indicated IGFBP2 overexpression was significantly correlated with overall survival in Asian patients (HR = 1.42, 95% CI = 1.18-1.72), Caucasian patients (HR = 2.20, 95% CI = 1.31-3.70), glioma (HR = 1.36, 95% CI = 1.03-1.79), and colorectal cancer (HR = 2.52, 95% CI = 1.43-4.44) and surgery subgroups (HR = 1.97, 95% CI = 1.50-2.58).

CONCLUSION

The meta-analysis showed that IGFBP2 expression was associated with worse prognosis in several tumors, and may serve as a potential prognostic biomarker in cancer patients.

Impact of the IGFBP3 A-202C polymorphism on susceptibility and clinicopathologic features of breast cancer

BACKGROUND

Insulin-like growth factor binding protein 3 (IGFBP3) plays an important role in cellular proliferation, differentiation, apoptosis, and mammary carcinogenesis. Genetic variations in IGFBP3 have been identified to influence the circulating IGFBP3 level. The present study determined the impact of an important promoter polymorphism (A-202C, rs2854744) on susceptibility and progression of breast cancer in a Chinese population.

METHODS

We genotyped the IGFBP3 A-202C polymorphism in a case-control study involving 465 breast cancer patients and 799 age-matched, cancer-free controls using the TaqMan method. Logistic regression was used to assess the genetic association between the occurrence and progression of breast cancer.

RESULTS

Compared with the wild genotype (-202AA), we found a statistically significant increased risk of breast cancer associated with the variant genotypes (CC vs. AA: OR=2.00, 95% CI=1.25-3.21; AC+CC vs. AA: OR=1.34, 95% CI=1.06-1.70). In the stratified analysis, the increased risk was more apparent among the subgroups of older subjects (OR=1.70, 95% CI=1.20-2.42). Furthermore, we found that patients carrying variant genotypes (AC+CC) had a significantly greater prevalence of large tumor size (OR=1.72, 95% CI=1.13-2.64; P=0.021).

CONCLUSION

Our results suggest that the functional IGFBP3 A-202C polymorphism may influence the susceptibility and progression of breast cancer in the Chinese population.

Ethnic background and genetic variation in the evaluation of cancer risk: a systematic review

The clinical use of genetic variation in the evaluation of cancer risk is expanding, and thus understanding how determinants of cancer susceptibility identified in one population can be applied to another is of growing importance. However there is considerable debate on the relevance of ethnic background in clinical genetics, reflecting both the significance and complexity of genetic heritage. We address this via a systematic review of reported associations with cancer risk for 82 markers in 68 studies across six different cancer types, comparing association results between ethnic groups and examining linkage disequilibrium between risk alleles and nearby genetic loci. We find that the relevance of ethnic background depends on the question. If asked whether the association of variants with disease risk is conserved across ethnic boundaries, we find that the answer is yes, the majority of markers show insignificant variability in association with cancer risk across ethnic groups. However if the question is whether a significant association between a variant and cancer risk is likely to reproduce, the answer is no, most markers do not validate in an ethnic group other than the discovery cohort's ancestry. This lack of reproducibility is not attributable to studies being inadequately populated due to low allele frequency in other ethnic groups. Instead, differences in local genomic structure between ethnic groups are associated with the strength of association with cancer risk and therefore confound interpretation of the implied physiologic association tracked by the disease allele. This suggest that a biological association for cancer risk alleles may be broadly consistent across ethnic boundaries, but reproduction of a clinical study in another ethnic group is uncommon, in part due to confounding genomic architecture. As clinical studies are increasingly performed globally this has important implications for how cancer risk stratifiers should be studied and employed.

Association between endometriosis and polymorphisms in insulin-like growth factor binding protein genes in Korean women

OBJECTIVE

Genetic factors are known to be associated with the development and progression of endometriosis, but the genes related to endometriosis have not been defined. Insulin-like growth factor binding proteins (IGFBPs) are believed to be involved in the proliferation and apoptosis of cells that play an important role in the pathophysiologic mechanism of endometriosis. This study aimed to determine the association between endometriosis and polymorphisms of the IGFBP genes in Korean women.

STUDY DESIGN

In a case-control study, the rs1995051, rs1065780 and c.759A>G single nucleotide polymorphisms (SNPs) in the IGFBP1 gene and the -672A>G, -202A>C and c.95C>G SNPs in the IGFBP3 gene were analyzed in 128 women with endometriosis and 108 normal control women.

RESULTS

The haplotype genotype composed of a combination of three IGFBP1 gene polymorphisms was not related to endometriosis, while the haplotype genotype of the IGFBP3 gene had a significant association with endometriosis. Women not carrying the AAG (-672A/-202A/c.95G) haplotype allele of three IGFBP3 gene polymorphisms have a 3.19-times higher risk of endometriosis compared with women with AAG homozygotes, and this trend was found in women with advanced endometriosis but not in women with early endometriosis.

CONCLUSIONS

The AAG haplotype allele of the -672A>G, -202A>C and c.95C>G polymorphisms in the IGFBP3 gene may be associated with advanced endometriosis in Korean women.

Genome-based prediction of breast cancer risk in the general population: a modeling study based on meta-analyses of genetic associations

BACKGROUND

Genome-wide association studies identified novel breast cancer susceptibility variants that could be used to predict breast cancer in asymptomatic women. This review and modeling study aimed to investigate the current and potential predictive performance of genetic risk models.

METHODS

Genotypes and disease status were simulated for a population of 10,000 women. Genetic risk models were constructed from polymorphisms from meta-analysis including, in separate scenarios, all polymorphisms or statistically significant polymorphisms only. We additionally investigated the magnitude of the odds ratios (OR) for 1 to 100 hypothetical polymorphisms that would be needed to achieve similar discriminative accuracy as available prediction models [modeled range of area under the receiver operating characteristic curve (AUC) 0.70-0.80].

RESULTS

Of the 96 polymorphisms that had been investigated in meta-analyses, 41 showed significant associations. AUC was 0.68 for the genetic risk model based on all 96 polymorphisms and 0.67 for the 41 significant polymorphisms. Addition of 50 additional variants, each with risk allele frequencies of 0.30, requires per-allele ORs of 1.2 to increase this AUC to 0.70, 1.3 to increase AUC to 0.75, and 1.5 to increase AUC to 0.80. To achieve AUC of 0.80, even 100 additional variants would need per-allele ORs of 1.3 to 1.7, depending on risk allele frequencies.

CONCLUSION

The predictive ability of genetic risk models in breast cancer has the potential to become comparable to that of current breast cancer risk models.

IMPACT

Risk prediction based on low susceptibility variants becomes a realistic tool in prevention of nonfamilial breast cancer.

IGFBP1 and IGFBP3 polymorphisms predict circulating IGFBP-3 levels among women from high-risk breast cancer families

The insulin-like growth factor (IGF) pathway has been implicated as risk modifier in premenopausal breast cancer. In this study, associations between single nucleotide polymorphisms (SNPs) and diplotypes in the IGFBP1 and IGFBP3 genes and circulating IGFBP-3 levels, BRCA family status and breast cancer among women from high-risk breast cancer families were investigated. Nine IGFBP1 and IGFBP3 SNPs were genotyped with PCR-based methods in 323 women. Nine IGFBP1 and ten IGFBP3 diplotypes were identified. Plasma IGFBP-3 levels obtained during cycle day 18-23 were available for 231 women, 87 current users of combined oral contraceptives and 144 non-users. IGFBP1 (rs1995051 and rs4988515) and IGFBP3 (rs2471551 and rs2854744) SNPs were associated with circulating IGFBP-3 levels (P < 0.05). IGFBP1 (low) diplotypes were associated with lower IGFBP-3 levels and were more common in BRCA2 families OR 2.05 (95%CI 0.97-4.30). IGFBP3 (high) diplotypes were associated with higher IGFBP-3 levels and were more common in BRCAX families OR 1.68 (95%CI 1.04-2.74). After adjusting the models for BRCA family status, both the BRCA1 and BRCA2 family status (P ≤ 0.006) and the IGFBP1 diplotype GTAC/ACAT (P = 0.004) were associated with lower IGFBP-3 levels. Similarly, both the BRCA1 and BRCA2 family status (P ≤ 0.03) and the IGFBP-3 diplotypes GCA/GCG (P = 0.007) and GCG/CCG (P = 0.002) were significantly associated with lower IGFBP-3 levels, adjusted for age, weight, OC use, and other IGFBP diplotypes. No individual SNP was associated with breast cancer. There were 23 cases of breast cancer and one IGFBP1 diplotype was associated with a decreased risk of breast cancer after age 18 (log rank P=0.05). In conclusion, independent effects from IGFBP1, IGFBP3 diplotypes, and BRCA family status on IGFBP-3 levels were observed. These factors may influence the risk of breast cancer among women from high-risk breast cancer families.

The p21 Ser31Arg polymorphism and breast cancer risk: a meta-analysis involving 51,236 subjects

Published data on the association between p21 Ser31Arg polymorphism and breast cancer risk are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. Crude ORs with 95% CIs were used to assess the strength of association between the p21 Ser31Arg polymorphism and breast cancer risk. The pooled ORs were performed for co-dominant model (Ser/Arg vs. Ser/Ser, Arg/Arg vs. Ser/Ser), dominant model (Arg/Arg + Ser/Arg vs. Ser/Ser), and recessive model (Arg/Arg vs. Ser/Arg + Ser/Ser). A total of 21 studies including 22,109 cases and 29,127 controls were involved in this meta-analysis. Overall, no significant associations were found between p21 Ser31Arg polymorphism and breast cancer risk when all studies pooled into the meta-analysis. In the subgroup analysis by ethnicity, significantly increased risk was found for Caucasians (Arg/Arg vs. Ser/Ser: OR 1.496, 95% CI 1.164-1.924; and recessive model: OR 1.492, 95% CI 1.161-1.919). When stratified by study design, statistically significantly elevated risk was found for population-based studies (Ser/Arg vs. Ser/Ser: OR 1.085, 95% CI 1.019-1.156). In conclusion, this meta-analysis suggests that the p21 Ser31Arg polymorphism may be associated with breast cancer development in Caucasian. However, large sample and representative population-based studies with homogeneous breast cancer patients and well-matched controls are warranted to confirm this finding.

Transforming growth factor-beta1 polymorphisms and breast cancer risk: a meta-analysis based on 27 case-control studies

The association between transforming growth factor-beta1 (TGF-beta1) gene polymorphisms and breast cancer risk has been widely reported, but results were somewhat controversial and underpowered. To derive a more precise estimation of the relationship between TGF-beta1 polymorphisms and breast cancer risk, we conducted a meta-analysis of all available case-control studies relating the T869C and/or C-509T polymorphisms of the TGF-beta1 gene to the risk of developing breast cancer. Eligible articles were identified by search of databases including MEDLINE, PubMed, Web of Science, EMBASE, and Chinese Biomedical Literature database (CBM) for the period up to March 2010. Finally, a total of 17 articles involving 27 case-control studies were identified, 25 with 20,022 cases and 24,423 controls for T869C polymorphism and eight with 10,633 cases and 13,648 controls for C-509T polymorphism. The pooled ORs were performed for the allele contrasts, additive genetic model, dominant genetic model and recessive genetic model, respectively. Subgroup analysis was also performed by ethnicity for T869C polymorphism. With respect to T869C polymorphism, no association was found in overall analysis (C vs. T: OR = 1.033, 95% CI = 0.996-1.072). In the subgroup analysis by ethnicity, significantly increased risk was found in Caucasian population (C vs. T: OR = 1.051, 95% CI = 1.018-1.085; CC vs. TT + TC: OR = 1.083, 95% CI = 1.019-1.151), but not in Asian population (C vs. T: OR = 1.054, 95% CI = 0.983-1.130). With respect to C-509T polymorphism, no significant association with breast cancer risk was demonstrated in overall analysis (T vs. C: OR = 0.986, 95% CI = 0.936-1.039). It can be concluded that potentially functional TGF-Beta1 T869C polymorphism may play a low penetrance role in breast cancer susceptibility in an ethnicity-specific manner.