Three novel functional polymorphisms in the promoter of FGFR2 gene and breast cancer risk: a HuGE review and meta-analysis

FGFR2 Controls Growth, Adhesion and Migration of Nontumorigenic Human Mammary Epithelial Cells by Regulation of Integrin β1 Degradation

The role of fibroblast growth factor receptor 2 (FGFR2), an important mediator of stromal paracrine and autocrine signals, in mammary gland morphogenesis and breast cancer has been extensively studied over the last years. However, the function of FGFR2 signalling in the initiation of mammary epithelial oncogenic transformation remains elusive. Here, FGFR2-dependent behaviour of nontumorigenic model of mammary epithelial cells was studied. In vitro analyses demonstrated that FGFR2 regulates epithelial cell communication with extracellular matrix (ECM) proteins. Silencing of FGFR2 significantly changed the phenotype of cell colonies in three-dimensional cultures, decreased integrins α2, α5 and β1 protein levels and affected integrin-driven processes, such as cell adhesion and migration. More detailed analysis revealed the FGFR2 knock-down-induced proteasomal degradation of integrin β1. Analysis of RNA-seq databases showed significantly decreased FGFR2 and ITGB1 mRNA levels in breast tumour samples, when compared to non-transformed tissues. Additionally, high risk healthy individuals were found to have disrupted correlation profiles of genes associated with FGFR2 and integrin signalling, cell adhesion/migration and ECM remodelling. Taken together, our results strongly suggest that FGFR2 loss with concomitant integrin β1 degradation is responsible for deregulation of epithelial cell-ECM interactions and this process may play an important role in the initiation of mammary gland epithelial tumorigenesis.

Associations of serum vitamin D and Fok I polymorphism of receptor gene with unexplained recurrent spontaneous abortion

Background: To investigate the associations of serum vitamin D and Fok I polymorphism of its receptor (VDR) with unexplained recurrent spontaneous abortion (URSA).

Methods: Ninety URSA patients and another 104 healthy pregnant women were selected as URSA and control groups, respectively. 25-Hydroxyvitamin D [25-(OH)D] level was detected by chemiluminescence. VDR gene Fok I polymorphism was analyzed by PCR, and the distribution of genotype frequency was calculated by Hardy-Weinberg equilibrium test. Association between Fok I polymorphism and susceptibility to URSA was investigated by logistic regression analysis.

Results: Gestational age, uterine height, waist circumference, 25-(OH)D level and proportions of Fok I FF and Ff genotypes were significantly lower in the URSA group (P<0.05). Compared with ff genotype, risk of URSA reduced for Ff and FF genotypes. Compared with allele f, risk of URSA was lower for allele F. 25-(OH)D level of ff genotype was significantly lower in the URSA group, which was lower than that of FF genotype (P<0.05). Compared with women with 25-(OH)D level >30 ng/mL and F allele (FF+Ff), the risk of URSA increased 2.45-, 2.43- and 5.34-fold for those with 25-(OH)D level >30 ng/mL and ff genotype, with 25-(OH)D level ≤30 ng/mL, and with ff genotype and 25-(OH)D level ≤30 ng/mL, respectively.

Conclusions: The 25-(OH)D level of the URSA group was significantly lower than that of normal pregnant women. Probably, VDR gene Fok I polymorphism is associated with URSA occurrence, and allele F decreases the risk. The risk of URSA dramatically increases in women with ff genotype and 25-(OH)D deficiency.

The Contribution of Race to Breast Tumor Microenvironment Composition and Disease Progression

Breast cancer is the second most commonly diagnosed cancer in American women following skin cancer. Despite overall decrease in breast cancer mortality due to advances in treatment and earlier screening, black patients continue to have 40% higher risk of breast cancer related death compared to white patients. This disparity in outcome persists even when controlled for access to care and stage at presentation and has been attributed to differences in tumor subtypes or gene expression profiles. There is emerging evidence that the tumor microenvironment (TME) may contribute to the racial disparities in outcome as well. Here, we provide a comprehensive review of current literature available regarding race-dependent differences in the TME. Notably, black patients tend to have a higher density of pro-tumorigenic immune cells (e.g., M2 macrophages, regulatory T cells) and microvasculature. Although immune cells are classically thought to be anti-tumorigenic, increase in M2 macrophages and angiogenesis may lead to a paradoxical increase in metastasis by forming doorways of tumor cell intravasation called tumor microenvironment of metastasis (TMEM). Furthermore, black patients also have higher serum levels of inflammatory cytokines, which provide a positive feedback loop in creating a pro-metastatic TME. Lastly, we propose that the higher density of immune cells and angiogenesis observed in the TME of black patients may be a result of evolutionary selection for a more robust immune response in patients of African geographic ancestry. Better understanding of race-dependent differences in the TME will aid in overcoming the racial disparity in breast cancer mortality.

FGFs/FGFRs-dependent signalling in regulation of steroid hormone receptors - implications for therapy of luminal breast cancer

Stromal stimuli mediated by growth factor receptors, leading to ligand-independent activation of steroid hormone receptors, have long been implicated in development of breast cancer resistance to endocrine therapy. Mutations in fibroblast growth factor receptor (FGFR) genes have been associated with a higher incidence and progression of breast cancer. Increasing evidence suggests that FGFR-mediated interaction between luminal invasive ductal breast carcinoma (IDC) and its microenvironment contributes to the progression to hormone-independence. Therapeutic strategies based on FGFR inhibitors hold promise for overcoming resistance to the ER-targeting treatment. A series of excellent reviews discuss a potential role of FGFR in development of IDC. Here, we provide a concise updated summary of existing literature on FGFR-mediated signalling with an emphasis on an interaction between FGFR and estrogen/progesterone receptors (ER/PR) in IDC. Focusing on the regulatory role of tumour microenvironment in the activity of steroid hormone receptors, we compile the available functional data on FGFRs-mediated signalling, as a fundamental mechanism of luminal IDC progression and failure of anti-ER treatment. We also highlight the translational value of the presented findings and summarize ongoing oncologic clinical trials investigating FGFRs inhibition in interventional studies in breast cancer.

Comprehensive Analysis of Germline Variants in Mexican Patients with Hereditary Breast and Ovarian Cancer Susceptibility

Hereditary breast and ovarian cancer syndrome (HBOC) represents 5⁻10% of all patients with breast cancer and is associated with high-risk pathogenic alleles in BRCA1/2 genes, but only for 25% of cases. We aimed to find new pathogenic alleles in a panel of 143 cancer-predisposing genes in 300 Mexican cancer patients with suspicion of HBOC and 27 high-risk patients with a severe family history of cancer, using massive parallel sequencing. We found pathogenic variants in 23 genes, including BRCA1/2. In the group of cancer patients 15% (46/300) had a pathogenic variant; 11% (33/300) harbored variants with unknown clinical significance (VUS) and 74% (221/300) were negative. The high-risk group had 22% (6/27) of patients with pathogenic variants, 4% (1/27) had VUS and 74% (20/27) were negative. The most recurrent mutations were the Mexican founder deletion of exons 9-12 and the variant p.G228fs in BRCA1, each found in 5 of 17 patients with alterations in this gene. Rare VUS with potential impact at the protein level were found in 21 genes. Our results show for the first time in the Mexican population a higher contribution of pathogenic alleles in other susceptibility cancer genes (54%) than in BRCA1/2 (46%), highlighting the high locus heterogeneity of HBOC and the necessity of expanding genetic tests for this disease to include broader gene panels.

Association between FGFR2 (rs2981582, rs2420946 and rs2981578) polymorphism and breast cancer susceptibility: a meta-analysis

The association between fibroblast growth factor receptor 2 (FGFR2) polymorphism and breast cancer (BC) susceptibility remains inconclusive. The purpose of this systematic review was to evaluate the relationship between FGFR2 (rs2981582, rs2420946 and rs2981578) polymorphism and BC risk. PubMed, Web of science and the Cochrane Library databases were searched before October 11, 2015 to identify relevant studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the strength of associations. Sensitivity and subgroup analyses were conducted. Thirty-five studies published from 2007 to 2015 were included in this meta-analysis. The pooled results showed that there was significant association between all the 3 variants and BC risk in any genetic model. Subgroup analysis was performed on rs2981582 and rs2420946 by ethnicity and Source of controls, the effects remained in Asians, Caucasians, population-based and hospital-based groups. We did not carryout subgroup analysis on rs2981578 for the variant included only 3 articles. This meta-analysis of case-control studies provides strong evidence that FGFR2 (rs2981582, rs2420946 and rs2981578) polymorphisms were significantly associated with the BC risk. For rs2981582 and rs2420946, the association remained significant in Asians, Caucasians, general populations and hospital populations. However, further large scale multicenter epidemiological studies are warranted to confirm this finding and the molecular mechanism for the association need to be elucidated further.

Association between rs11200014, rs2981579, and rs1219648 polymorphism and breast cancer susceptibility: A meta-analysis

BACKGROUND

Research on the polymorphism of breast cancer (BC) helps to search the BC susceptibility gene for mass screening, early diagnosis, and gene therapy, which has become a hotspot in BC research field. Previous studies have suggested associations between rs11200014, rs2981579, and rs1219648 polymorphisms and cancer risk. The aim of this study was to evaluate the relationship between rs11200014, rs2981579, and rs1219648 polymorphism and BC risk.

METHODS

PubMed, Web of science, and the Cochrane Library databases were searched before October 11, 2015, to identify relevant studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the strength of associations. Sensitivity and subgroup analyses were conducted. All included cases should have been diagnosed by a pathological examination.

RESULTS

Twenty-six studies published from 2007 to 2015 were included in this meta-analysis. The pooled results showed that there was a significant association between all the 3 variants and BC risk in any genetic model. When stratified by Source of controls, the results showed the same association between rs2981579 polymorphism and BC susceptibility in hospital-based (HB) group, although there was not any genetic model attained statistical correlation in population-based (PB) group. Subgroup analysis was performed on rs1219648 by ethnicity and Source of controls, and the effects remained in Asians, Caucasians, HB, and PB groups.

CONCLUSION

This meta-analysis of case-control studies provides strong evidence that fibroblast growth factor 2 (FGFR2; rs11200014, rs2981579, and rs1219648) polymorphisms are significantly associated with the BC risk. For rs2981579, the association remained in hospital populations, while not in general populations. For rs1219648, the association remained in Asians, Caucasians, hospital populations, and general populations. However, further large-scale multicenter epidemiological studies are warranted to confirm this finding and the molecular mechanism for the associations need to be elucidated in future studies.

Fibroblast Growth Factor Receptor 2 Signaling in Breast Cancer

Fibroblast growth factor receptor 2 (FGFR2) is a membrane-spanning tyrosine kinase that mediates signaling for FGFs. Recent studies detected various point mutations of FGFR2 in multiple types of cancers, including breast cancer, lung cancer, gastric cancer, uterine cancer and ovarian cancer, yet the casual relationship between these mutations and tumorigenesis is unclear. Here we will discuss possible interactions between FGFR2 signaling and several major pathways through which the aberrantly activated FGFR2 signaling may result in breast cancer development. We will also discuss some recent developments in the discovery and application of therapies and strategies for breast cancers by inhibiting FGFR2 activities.

Association between fibroblast growth factor receptor-2 gene polymorphism and risk of breast cancer in Chinese populations: A HuGE review and meta-analysis

AIM OF STUDY

To evaluate the effect of fibroblast growth factor receptor.2. (FGFR2) on genetic susceptibility for breast cancer. (BC) in Chinese populations.

MATERIALS AND METHODS

A computerized literature search was carried out in PubMed, Chinese Biomedical Database. (CBM), and Chinese National Knowledge Infrastructure. (CNKI) to collect relevant articles. Pooled odds ratio. (OR) and 95% confidence interval. (CI) were used to assess the strength of the associations.

RESULTS

A total of 21 articles involving a total of 15 polymorphisms of the FGFR2 gene were included in the meta-analysis. Due to the limited studies for rs17102287, rs2981578, rs3135718, rs3803662, rs3750817, rsl0510097, rsl7542768, rs13387042, and rs1982073; we only pooled the six polymorphisms. (rs11200014, rs1219648, rs2420946, rs2912778, rs2981579, and rs2981582) into this meta.

ANALYSIS

Overall, significantly increased BC risk was associated with five polymorphisms. (rs2981579, rs2981582, rs1219648, rs2420946, and rs2912778) when all studies were pooled into the meta.

ANALYSIS

When stratified by ethnicity and source of controls, similar results were also detected. However, for rs2981579 no significant association was found among Chinese Han in all genetic models.

CONCLUSION

Our meta-analysis suggests that FGFR2 is likely an important genetic marker contributing to susceptibility of BC. We recommend that these single nucleotide polymorphisms to be included in future association studies and functional assays.

Variants of FGFR2 and their associations with breast cancer risk: a HUGE systematic review and meta-analysis

Extensive epidemiological studies have demonstrated that there are associations between variants in intron 2 of FGFR2 and the breast cancer risk in various populations; however, the relationships are not yet conclusively established. To comprehensively review the epidemiological studies showing associations between the variants of FGFR2 and the breast cancer risk, and to establish correlations via a meta-analysis. The PubMed and MEDLINE databases were searched for eligible studies. The associations between the variants and breast cancer risk were evaluated using a random-effects model. The heterogeneity among the studies and the potential publication bias were also evaluated. Fifty-three studies with a total of 121,740 cases and 198,549 controls have examined the associations between 23 variants in intron 2 of FGFR2 and the breast cancer risk. The relationships for the 10 most frequently evaluated variants-rs1078806, rs11200014, rs1219648, rs2420946, rs2981578, rs2981579, rs2981582, rs3135718, rs10736303, and rs3750817-were synthesized based on a meta-analysis. Interestingly, we found that all 10 variants were significantly associated with the risk of breast cancer. In studies stratified by ethnicity, we found that the associations were more notable in Caucasians and Asians compared to Africans. Similar pooled results were found in population-based and hospital-based case-control studies and in studies with small and large sample sizes. FGFR2 is a breast cancer susceptibility gene, and various variants of FGFR2 are significantly associated with the breast cancer risk. However, the biological mechanisms underlying the associations need to be elucidated in future studies.

Bridging external fixation versus non-bridging external fixation for unstable distal radius fractures: A systematic review and meta-analysis

OBJECTIVE

A systematic review and meta-analysis was conducted to compare the relative effectiveness of bridging external fixation and non-bridging external fixation for distal radius fractures treatment.

METHOD

Relevant literature were comprehensively searched using the PubMed, Springer Link, Karger Medical and Scientific Publishers, Chinese Biomedical Database (CBM) and Chinese National Knowledge Infrastructure (CNKI) databases without any language restrictions. STATA Version 12.0 software and Comprehensive Meta-analysis 2.0 were applied.

RESULTS

A total of 905 patients with distal radius fracture from six eligible cohort studies were selected for statistical analysis. Our meta-analysis results indicate that the non-bridging cases had a higher risk of pin track infection, rupture of the extensor pollicis longus and nerve injury than the bridging cases. Subgroup analysis stratified by country indicated non-bridging patients showed evidence of an increased risk of pin track infection and higher risk of rupture of the extensor pollicis longus compared with the patients treated with bridging external fixation in the UK population. The follow-up results showed flexion degree of patients treated with non-bridging external fixation was slightly better than that of patients treated with bridging external fixation (P < 0.05).

CONCLUSION

There is evidence in our systematic review and meta-analysis to support that bridging external fixation can reduce the incidence of pin tract infections and nerve injury compared to non-bridging external fixation, but have no significant difference in other complications and the recovery of wrist joint function. Bridging external fixation could therefore be a better choice in patients with distal radius fractures.

Association between IFN-γ genetic polymorphisms and susceptibility to hepatitis B virus infection: A meta-analysis

BACKGROUND

Hepatitis B virus (HBV) infection has become a global health burden because of its contagious mode of transmission and the resultant long-term liver damage.

AIM

To investigate how the polymorphisms of the IFN-γ gene, particularly the IFN-γ +874T/A (rs2430561) single nucleotide polymorphism (SNP), influence susceptibility to HBV infection.

SUBJECTS AND METHODS

Relevant articles were identified by a comprehensive literature search covering the following computerised bibliographic databases. Eleven independent case-control studies were ultimately selected for the current meta-analysis, comprising a total of 1527 HBV cases and 1467 healthy subjects.

RESULTS

The results in the current meta-analysis showed that carriers of the IFN-γ A allele were more likely to develop HBV infection than those without in all five genetic models (all p < 0.05). According to the ethnicity-based sub-group analysis, a significant difference of the IFN-γ rs2430561 T > A polymorphism was detected associated with the increased risk of HBV infection in Asians and European-derived populations in the majority of the groups.

CONCLUSIONS

The results implicate a possible relationship between the IFN-γ rs2430561 T > A polymorphism and the risk of HBV infection. Therefore, IFN-γ genetic polymorphisms might be important in determining an individual's susceptibility to HBV infection.

Methylation of the FGFR2 gene is associated with high birth weight centile in humans

AIMS

This study examined links between DNA methylation and birth weight centile (BWC), and explored the impact of genetic variation.

MATERIALS & METHODS

Using HumanMethylation450 arrays, we examined candidate gene-associated CpGs in cord blood from newborns with low (<15th centile), medium (40-60th centile) and high (>85th centile) BWC (n = 12). Candidates were examined in an investigation cohort (n = 110) using pyrosequencing and genotyping for putative methylation-associated polymorphisms performed using standard PCR.

RESULTS

Array analysis identified 314 candidate genes associated with BWC extremes, four of which showed ≥ 4 BWC-linked CpGs. Of these, PM20D1 and MI886 suggested genetically determined methylation levels. However, methylation at three CpGs in FGFR2 remained significantly associated with high BWC (p = 0.004-0.027).

CONCLUSION

We identified a novel biologically plausible candidate (FGFR2) for with BWC that merits further study.

Association analyses of FGFR2 gene polymorphisms with femoral neck bone mineral density in Chinese Han population

Femoral neck (FN) bone mineral density (BMD) is the most important risk phenotype for osteoporosis and has been used as a reference standard for describing osteoporosis. Identification of genetic variations associated with FN BMD may provide potential targets for therapeutic studies. Given the important biological role of FGFR2 gene involved in bone, we tested the associations between FGFR2 polymorphisms and FN BMD in 1,300 Chinese Han subjects. Of the 28 total SNPs, 2 SNPs, namely rs11200014 and rs1078806, were significantly associated with FN BMD under dominant model (P = 0.0014 and 0.0012, respectively) after conservative Bonferroni correction. The two SNPs were in complete linkage disequilibrium. In addition, haplotype-based association tests identified two haplotypes significantly associated with FN BMD, including one haplotype in block 4 where the two SNPs located. However, different from previous studies in white older men, we did not detect any significant association in sex-stratified analyses. In summary, our findings suggest that the FGFR2 gene may play an important role in variation in FN BMD in Chinese Han population, independent of gender effects. Further studies performed in multiple and large samples are needed to elucidate the underlying molecular mechanism and pathophysiology of osteoporosis.

Relationships between PTEN gene mutations and prognosis in glioma: a meta-analysis

We conducted a meta-analysis in order to investigate the relationships between PTEN gene mutations and the prognosis in glioma. The following electronic databases were searched for relevant articles without any language restrictions: Web of Science (1945 ~ 2013), the Cochrane Library Database (Issue 12, 2013), PubMed (1966 ~ 2013), EMBASE (1980 ~ 2013), CINAHL (1982 ~ 2013), and the Chinese Biomedical Database (CBM) (1982 ~ 2013). Meta-analyses were conducted using the STATA software (Version 12.0, Stata Corporation, College Station, Texas USA). Hazard ratio (HR) with its corresponding 95 % confidence interval (95%CI) was calculated. Six independent cohort studies with a total of 357 glioma patients met our inclusion criteria. Our meta-analysis results indicated that glioma patients with PTEN gene mutations exhibited a significantly shorter overall survival (OS) than those without PTEN gene mutations (HR = 3.66, 95%CI = 2.02 ~ 5.30, P < 0.001). Ethnicity-stratified subgroup analysis demonstrated that PTEN gene mutations were closely linked to poor prognosis in glioma among Americans (HR = 3.72, 95%CI = 1.72 ~ 5.73, P < 0.001), while similar correlations were not observed among populations in Sweden, Italy, and Malaysia (all P > 0.05). Our meta-analysis provides direct and strong evidences for the speculation of PTEN gene mutations' correlation with poor prognosis of glioma patients.

Small molecule inhibition of fibroblast growth factor receptors in cancer

Fibroblast growth factors (FGFs) signal through FGF receptors (FGFRs), which are a sub-family of the superfamily of receptor tyrosine kinases, to regulate human development and metabolism. Uncontrolled FGF signaling is responsible for diverse array of developmental disorders, most notably skeletal syndromes due to FGFR gain-of-function mutations. Studies in the last few years have provided significant evidence for the importance of FGF signaling in the pathogenesis of diverse cancers, including endometrial and bladder cancers. FGFs are both potent mitogenic and angiogenic factors and can contribute to carcinogenesis by stimulating cell proliferation and tumor angiogenesis. Gene knockout and pharmacological inhibition of FGFRs in in vivo and in vitro models validate FGFRs as a target for cancer treatment. Considerable efforts are being expended to develop specific, small-molecule inhibitors for treating FGFR-driven cancers. Recent reviews on the FGF/FGFR system have focused primarily on signaling, pathophysiology, and functions in cancer. In this article, we review the key roles of FGFR in cancer, provide an update on the status of clinical trials with small-molecule FGFR inhibitors, and discuss how the current structural data on FGFR kinases guide the design and characterization of new FGFR inhibitors.

Genetic variants in FGFR2 and MAP3K1 are associated with the risk of familial and early-onset breast cancer in a South-American population

Genome-Wide Association Studies have identified several loci associated with breast cancer (BC) in populations of different ethnic origins. One of the strongest associations was found in the FGFR2 gene, and MAP3K1 has been proposed as a low-penetrance BC risk factor. In this study, we evaluated the associations among FGFR2 SNPs rs2981582, rs2420946, and rs1219648; and MAP3K1 rs889312, with BC risk in 351 BRCA1/2-negative Chilean BC cases and 802 controls. All the SNPs studied were significantly associated with increased BC risk in familial BC and in non-familial early-onset BC, in a dose-dependent manner. Subjects with 3 risk alleles were at a significantly increased risk of BC compared with subjects with 0-2 risk alleles, in both familial BC and early-onset non-familial BC (OR = 1.47, 95 % CI 1.04-2.07, P = 0.026 and OR = 2.04 95 % CI 1.32-3.24, P < 0.001, respectively). In the haplotype analysis, the FGFR2 rs2981582 T / rs2420946 T / rs1219648 G haplotype (ht2) was associated with a significantly increased BC risk compared with the rs2981582 C / rs2420946 C / rs1219648 A haplotype in familial BC and in non-familial early-onset BC (OR = 1.32, 95 % CI 1.06-1.65, P = 0.012; OR = 1.46, 95 % CI 1.11-1.91, P = 0.004, respectively). When the FGFR2 ht2 and MAP3K1 rs889312 were evaluated as risk alleles, the risk of BC increased in a dose-dependent manner as the number of risk alleles increased (P trend <0.0001), indicating an additive effect. Nevertheless, there is no evidence of an interaction between FGFR2 ht2 and the MAP3K1 rs889312 C allele. These findings suggest that genetic variants in the FGFR2 and MAP3K1 genes may contribute to genetic susceptibility to BC.