Several neuroblastoma (NB) susceptibility loci have been identified within LINC00340, BARD1, LMO1, DUSP12, HSD17B12, DDX4, IL31RA, HACE1 and LIN28B by genome-wide association (GWA) studies including European American individuals. To validate and comprehensively evaluate the impact of the identified NB variants on disease risk and phenotype, we analyzed 16 single nucleotide polymorphisms (SNPs) in an Italian population (370 cases and 809 controls). We assessed their regulatory activity on gene expression in lymphoblastoid (LCLs) and NB cell lines. We evaluated the cumulative effect of the independent loci on NB risk and high-risk phenotype development in Italian and European American (1627 cases and 2575 controls) populations. All NB susceptibility genes replicated in the Italian dataset except for DDX4 and IL31RA, and the most significant SNP was rs6435862 in BARD1 (P = 8.4×10–15). BARD1 showed an additional and independent SNP association (rs7585356). This variant influenced BARD1 mRNA expression in LCLs and NB cell lines. No evidence of epistasis among the NB-associated variants was detected, whereas a cumulative effect of risk variants on NB risk (European Americans: P
trend = 6.9×10–30, Italians: P
trend = 8.55×1013) and development of high-risk phenotype (European Americans: P
trend = 6.9×10–13, Italians: P
trend = 2.2×10–1) was observed in a dose-dependent manner. These results provide further evidence that the risk loci identified in GWA studies contribute to NB susceptibility in distinct populations and strengthen the role of BARD1 as major genetic contributor to NB risk. This study shows that even in the absence of interaction the combination of several low-penetrance alleles has potential to distinguish subgroups of patients at different risks of developing NB.
Chemotherapy induces apoptosis and tumor regression primarily through activation of p53-mediated transcription. Neuroblastoma is a p53 wild type malignancy at diagnosis and repression of p53 signaling plays an important role in its pathogenesis. Recently developed small molecule inhibitors of the MDM2-p53 interaction are able to overcome this repression and potently activate p53 dependent apoptosis in malignancies with intact p53 downstream signaling. We used the small molecule MDM2 inhibitor, Nutlin-3a, to determine the p53 drug response signature in neuroblastoma cells. In addition to p53 mediated apoptotic signatures, GSEA and pathway analysis identified a set of p53-repressed genes that were reciprocally over-expressed in neuroblastoma patients with the worst overall outcome in multiple clinical cohorts. Multifactorial regression analysis identified a subset of four genes (CHAF1A, RRM2, MCM3, and MCM6) whose expression together strongly predicted overall and event-free survival (p<0.0001). The expression of these four genes was then validated by quantitative PCR in a large independent clinical cohort. Our findings further support the concept that oncogene-driven transcriptional networks opposing p53 activation are essential for the aggressive behavior and poor response to therapy of high-risk neuroblastoma.
Common variants in DNA may predispose to onset and progression of neuroblastoma (NB). The genotype GG of single nucleotide polymorphism (SNP) rs1800795 (−174 G>C) in interleukin (IL)-6 promoter has been associated with lower survival of high-risk NB.
To evaluate the impact of IL-6 SNP rs1800795 on disease risk and phenotype, we analyzed 326 Italian NB patients and 511 controls. Moreover, we performed in silico and quantitative Real Time (qRT)-PCR analyses to evaluate the influence of the SNP on gene expression in 198 lymphoblastoid cell lines (LCLs) and in 31 NB tumors, respectively. Kaplan-Meier analysis was used to verify the association between IL-6 gene expression and patient survival. We found that IL-6 SNP is not involved in susceptibility to NB development. However, our results show that a low frequency of genotype CC is significantly associated with a low overall survival, advanced stage, and high-risk phenotype. The in silico (p = 2.61×10−5) and qRT-PCR (p = 0.03) analyses showed similar trend indicating that the CC genotype is correlated with increased level of IL-6 expression. In report gene assay, we showed that the −174 C variant had a significantly increased transcriptional activity compared with G allele (p = 0.0006). Moreover, Kaplan-Meier analysis demonstrated that high levels of IL-6 are associated with poor outcome in children with NB in two independent gene expression array datasets.
The biological effect of SNP IL-6–174 G>C in relation to promotion of cancer progression is consistent with the observed decreased survival time. The present study suggests that SNP IL-6–174 G>C may be a useful marker for NB prognosis.
In order to supplement the cytopathological assessment of thyroid tumors, there is a need for new markers to correctly diagnose malignant thyroid lesions and avoid unnecessary and potentially harmful therapies for patients. The immunohistochemical expression of galectin-3 is currently considered to be the most accurate stand-alone marker for thyroid cancer diagnosis. The aim of this study was to establish whether the methylation state of the galectin-3 gene is a candidate molecular marker for thyroid malignancy. Thyroid specimens from 50 patients were analyzed, including 5 normal thyroid, 3 goiters, 39 papillary and 3 anaplastic thyroid carcinoma cases. High-resolution methylation analyses was performed to investigate the methylation state of a large genomic region (from −89 to +408) encompassing the galectin-3 transcriptional start site. Within this region, 5 CpG sites (nucleotide positions +134, +137, +142, +147 and +156) were observed to be differentially methylated among the samples and were further analyzed by the quantitative pyrosequencing technique. The hypomethylation of the +134, +137, +142, +147 and +156 CpG sites was observed to be markedly associated with cancer. Although the methylation degree of each single site was highly variable in non-neoplastic tissues, the average methylation state of the 5 CpG sites clearly distinguished cancer from the nonneoplastic thyroid tissues.
galectin-3; human thyroid cancer; DNA methylation; tumor marker
Neuroblastoma is a cancer of the sympathetic nervous system that accounts for approximately 10% of all pediatric oncology deaths1. Here we report on a genome-wide association study of 2,817 neuroblastoma cases and 7,473 controls. We identified two new associations at 6q16, the first within HACE1 (rs4336470; combined P = 2.7 × 10−11, odds ratio 1.26, 95% CI: 1.18–1.35) and the second within LIN28B (rs17065417; combined P = 1.2 × 10−8, odds ratio 1.38, 95% CI: 1.23–1.54). Expression of LIN28B and let-7 miRNA correlated with rs17065417 genotype in neuroblastoma cell lines, and we observed significant growth inhibition upon depletion of LIN28B specifically in neuroblastoma cells homozygous for the risk allele. Low HACE1 and high LIN28B expression in diagnostic primary neuroblastomas were associated with worse overall survival (P = 0.008 and 0.014, respectively). Taken together, we show that common variants in HACE1 and LIN28B influence neuroblastoma susceptibility and that both genes likely play a role in disease progression.
The mechanisms underlying genetic susceptibility at loci discovered by genome-wide association study (GWAS) approaches in human cancer remain largely undefined. In this study we characterized the high-risk neuroblastoma association at the BRCA1-related locus, BARD1, showing that disease-associated variations correlate with increased expression of the oncogenically activated isoform, BARD1β. In neuroblastoma cells, silencing of BARD1β showed genotype-specific cytotoxic effects, including decreased substrate-adherent, anchorage-independent, and foci growth. In established murine fibroblasts, overexpression of BARD1β was sufficient for neoplastic transformation. BARD1β stabilized the Aurora family of kinases in neuroblastoma cells, suggesting both a mechanism for the observed effect and a potential therapeutic strategy. Together, our findings identify BARD1β as an oncogenic driver of high-risk neuroblastoma tumorigenesis, and more generally, they illustrate how robust GWAS signals offer genomic landmarks to identify molecular mechanisms involved in both tumor initiation and malignant progression. The interaction of BARD1β with the Aurora family of kinases lends strong support to the ongoing work to develop Aurora kinase inhibitors for clinically aggressive neuroblastoma.
genome-wide association; neuroblastoma; BARD1; cancer susceptibility genes; functional genomics; oncogenes; genotype-phenotype correlations
Neuroblastoma is a childhood cancer of the sympathetic nervous system that accounts for approximately 10% of all paediatric oncology deaths1,2. To identify genetic risk factors for neuroblastoma, we performed a genome-wide association study (GWAS) on 2,251 patients and 6,097 control subjects of European ancestry from four case series. Here we report a significant association within LIM domain only 1 (LMO1) at 11p15.4 (rs110419, combined P = 5.2 × 10−16, odds ratio of risk allele = 1.34 (95% confidence interval 1.25–1.44)). The signal was enriched in the subset of patients with the most aggressive form of the disease. LMO1 encodes a cysteine-rich transcriptional regulator, and its paralogues (LMO2, LMO3 and LMO4) have each been previously implicated in cancer. In parallel, we analysed genome-wide DNA copy number alterations in 701 primary tumours. We found that the LMO1 locus was aberrant in 12.4% through a duplication event, and that this event was associated with more advanced disease (P < 0.0001) and survival (P = 0.041). The germline single nucleotide polymorphism (SNP) risk alleles and somatic copy number gains were associated with increased LMO1 expression in neuroblastoma cell lines and primary tumours, consistent with a gain-of-function role in tumorigenesis. Short hairpin RNA (shRNA)-mediated depletion of LMO1 inhibited growth of neuroblastoma cells with high LMO1 expression, whereas forced expression of LMO1 in neuroblastoma cells with low LMO1 expression enhanced proliferation. These data show that common polymorphisms at the LMO1 locus are strongly associated with susceptibility to developing neuroblastoma, but also may influence the likelihood of further somatic alterations at this locus, leading to malignant progression.
Common variable immunodeficiency is the most common form of symptomatic primary antibody failure in adults and children. Replacement immunoglobulin is the standard treatment of these patients. By using a differential proteomic approach based on 2D-DIGE, we examined serum samples from normal donors and from matched, naive, and immunoglobulin-treated patients. The results highlighted regulated expression of serum proteins in naive patients. Among the identified proteins, clusterin/ApoJ serum levels were lower in naive patients, compared to normal subjects. This finding was validated in a wider collection of samples from newly enrolled patients. The establishment of a cellular system, based on a human hepatocyte cell line HuH7, allowed to ascertain a potential role in the regulation of CLU gene expression by immunoglobulins.
Mortality is high in patients with esophageal carcinoma as tumors are rarely detected before the disease has progressed to an advanced stage. Here, we sought to isolate cell-free DNA released into the plasma of patients with esophageal carcinoma, to analyze copy number variations of marker genes in the search for early detection of tumor progression.
Plasma of 41 patients with esophageal carcinoma was prospectively collected before tumor resection and chemotherapy. Our dataset resulted heterogeneous for clinical data, resembling the characteristics of the tumor. DNA from the plasma was extracted to analyze copy number variations of the erbB2 gene using real-time PCR assays.
The real-time PCR assays for erbB2 gene showed significant (P = 0.001) copy number variations in the plasma of patients with esophageal carcinoma, as compared to healthy controls with high sensitivity (80%) and specificity (95%). These variations in erbB2 were negatively correlated to the progression free survival of these patients (P = 0.03), and revealed a further risk category stratification of patients with low VEGF expression levels.
The copy number variation of erbB2 gene from plasma can be used as prognostic marker for early detection of patients at risk of worse clinical outcome in esophageal cancer.
esophageal carcinoma; cell-free DNA; erbB2 copy number variation; prognostic marker; CTCs
Neuroblastoma is a malignant neoplasm of the developing sympathetic nervous system that is notable for its phenotypic diversity. High-risk patients typically have widely disseminated disease at diagnosis and a poor survival probability, but low-risk patients frequently have localized tumors that are almost always cured with little or no chemotherapy. Our genome-wide association study (GWAS) has identified common variants within FLJ22536, BARD1, and LMO1 as significantly associated with neuroblastoma and more robustly associated with high-risk disease. Here we show that a GWAS focused on low-risk cases identified SNPs within DUSP12 at 1q23.3 (P = 2.07×10−6), DDX4 and IL31RA both at 5q11.2 (P = 2.94×10−6 and 6.54×10−7 respectively), and HSD17B12 at 11p11.2 (P = 4.20×10−7) as being associated with the less aggressive form of the disease. These data demonstrate the importance of robust phenotypic data in GWAS analyses and identify additional susceptibility variants for neuroblastoma.
Neuroblastoma is the most common solid tumor outside the central nervous system and is accountable for 10% of the mortality rate of all children's cancers. It has distinctive clinical behaviors and is categorized into different risk groups: high-risk, intermediate-risk, and low-risk. Genome-wide association studies have reported a number of genetic variations predisposing to high-risk neuroblastoma. This study focuses on the low-risk neuroblastoma group and identifies four novel genes (DUSP12, DDX4, IL31RA, and HSD17B12) at three distinct genomic positions that harbor disease-causing variants. This study also reports several gene sets that are enriched in overall neuroblastoma as well as in both high-risk and low-risk groups. Also of importance is that this study adopts a new computational method that identifies genes, instead of only one single nucleotide polymorphism, as disease-causing variants. Shown to have superior power of detection genome-wide association signals for neuroblastoma, the methodology presented in this study has great potential applications in case-control association studies in other diseases.
Hepatocellular carcinoma is one of the most common cancers worldwide. Despite several efforts to elucidate hepatocellular carcinoma molecular pathogenesis, it is still not fully understood. To acquire further insights into the molecular mechanisms of hepatocellular carcinoma, we performed a systematic functional genomic approach on human HuH-7 and JHH-6 cells. The subsequent analysis of the differentially expressed genes in human specimens revealed a molecular signature of 11 genes from which we selected the LGALS1 gene, which was overexpressed in hepatocellular carcinoma. The expression analysis in humans of Galectin-1 (Gal-1), the protein encoded by LGALS1, showed a Gal-1 preferential accumulation in the stromal tissue around hepatocellular carcinoma tumors. Moreover, a significant association between increased expression of Gal-1 in hepatocellular carcinoma and the presence of metastasis was observed. Interestingly, Gal-1 overexpression resulted in an increase of cell migration and invasion. In conclusion, this study provides a portfolio of targets useful for future investigations into molecular marker–discovery studies on a large number of patients and functional assays. In addition, our data provide evidence that Gal-1 plays a role in hepatocellular carcinoma cell migration and invasion, and we suggest that further studies should be conducted to fully establish the role of Gal-1 in hepatocellular carcinoma pathogenesis and evaluate Gal-1 as a potential molecular therapeutic target.
We conducted a SNP-based genome-wide association study (GWAS) focused on the high-risk subset of neuroblastoma1. As our previous unbiased GWAS showed strong association of common 6p22 SNP alleles with aggressive neuroblastoma2, we now restricted our analysis to 397 high-risk cases compared to 2,043 controls. We detected new significant association of six SNPs at 2q35 within the BARD1 gene locus (Pallelic = 2.35×10−9 − 2.25×10−8). Each SNP association was confirmed in a second series of 189 high-risk cases and 1,178 controls (Pallelic = 7.90×10−7 − 2.77×10−4). The two most significant SNPs (rs6435862, rs3768716) were also tested in two additional independent high-risk neuroblastoma case series, yielding combined allelic odds-ratios of 1.68 each (P = 8.65×10−18 and 2.74×10−16, respectively). Significant association was also found with known BARD1 nsSNPs. These data show that common variation in BARD1 contributes to the etiology of the aggressive and most clinically relevant subset of human neuroblastoma.
Neuroblastoma is a malignancy of the developing sympathetic nervous system that most commonly affects young children and is often lethal. The etiology of this embryonal cancer is not known.
We performed a genome-wide association study by first genotyping 1,032 neuroblastoma patients and 2,043 controls of European descent using the Illumina HumanHap550 BeadChip. Three independent groups of neuroblastoma cases (N=720) and controls (N=2128) were then genotyped to replicate significant associations.
We observed highly significant association between neuroblastoma and the common minor alleles of three single nucleotide polymorphisms (SNPs) within a 94.2 kilobase (Kb) linkage disequilibrium block at chromosome band 6p22 containing the predicted genes FLJ22536 and FLJ44180 (P-value range = 1.71×10-9-7.01×10-10; allelic odds ratio range 1.39-1.40). Homozygosity for the at-risk G allele of the most significantly associated SNP, rs6939340, resulted in an increased likelihood of developing neuroblastoma of 1.97 (95% CI 1.58-2.44). Subsequent genotyping of these 6p22 SNPs in the three independent case series confirmed our observation of association (P=9.33×10-15 at rs6939340 for joint analysis). Furthermore, neuroblastoma patients homozygous for the risk alleles at 6p22 were more likely to develop metastatic (Stage 4) disease (P=0.02), show amplification of the MYCN oncogene in the tumor cells (P=0.006), and to have disease relapse (P=0.01).
Common genetic variation at chromosome band 6p22 is associated with susceptibility to neuroblastoma.
Hepatitis B virus (HBV) is one of the major etiological factors responsible for the development of hepatocellular carcinoma (HCC). We used a transgenic mouse, containing HBV sequences, as a model system to unravel the molecular mechanisms of hepatocarcinogenesis induced by HBV. We chose this animal model because it consistently develops liver cancer after intermediate steps that mimic the natural history of HBV infection in humans. In this study, we focus our attention on the early events leading to liver cancer. We compared the gene expression profile of 3-month-old transgenic mice with that of 3-month-old wild-type (wt) animals. In the transgenic mouse, microarray data analysis showed a total of 45 significantly differentially expressed genes, 25 highly expressed (fold change ≥2; P = 0.0025), and 20 downregulated (fold change ≤0.5; P = 0.0025). These genes belong to several different functional categories such as the regulation of immunological response, transcription, intracellular calcium ion mobilization, regulation of cell cycle and proliferation, NF-κb signal transduction cascades, and apoptosis. In particular, the upregulation of the antiapoptotic gene NuprI and the downregulation of the proapoptotic gene Bnip3 were found. This observation was supported by an in vitro apoptosis assay that showed downregulation of apoptosis in hepatocytes of HBV transgenic mouse compared with wt mice treated with staurosporine. In conclusion, our experimental approach allowed identification of new genes modulated by HBV and showed that the apoptotic process was deregulated in transgenic mouse hepatocytes. These data shed light on one possible mechanism by which HBV induces hepatocarcinogenesis.
Congenital Dyserythropoietic Anemia type II is an autosomal recessive disorder characterized by unique abnormalities in the differentiation of cells of the erythroid lineage. The vast majority of CDA II cases result from mutations in the SEC23B gene. To date, 53 different causative mutations have been reported in 86 unrelated cases (from the CDA II European Registry), 47 of them Italian. We have now identified SEC23B mutations in 23 additional patients, 17 Italians and 6 non-Italian Europeans. The relative allelic frequency of the mutations was then reassessed in a total of 64 Italian and 45 non-Italian unrelated patients. Two mutations, E109K and R14W, account for over one-half of the cases of CDA II in Italy. Whereas the relative frequency of E109K is similar in Italy and in the rest of Europe (and is also prevalent in Moroccan Jews), the relative frequency of R14W is significantly higher in Italy (26.3% vs. 10.7%). By haplotype analysis we demonstrated that both are founder mutations in the Italian population. By using the DMLE+ program our estimate for the age of the E109K mutation in Italian population is ≈2,200 years; whereas for the R14W mutation it is ≈3,000 years. We hypothesize that E109K may have originated in the Middle East and may have spread in the heyday of the Roman Empire. Instead, R14W may have originated in Southern Italy. The relatively high frequency of the R14W mutation may account for the known increased prevalence of CDA II in Italy. Am. J. Hematol. 86:727–732, 2011. © 2011 Wiley-Liss, Inc.