Citations

The common polymorphism SCN5A-S1103Y (∼13% allelic frequency in African Americans) is a risk factor for arrhythmia, sudden unexplained death (SUD), and sudden infant death syndrome. Prompted by a case of autopsy-negative SUD in a 23-year-old African American man who collapsed while playing football, we hypothesized that S1103Y interacted with other SCN5A variants to pathologically modify sodium current ( I Na ). Mutational analysis of arrhythmia-associated genes in the victim revealed the variants SCN5A-R680H and SCN5A-S1103Y. These variants were made both separately and in the same cDNA construct of the alternative splice variant backgrounds (SCN5A-Q1077del and Q1077) and expressed in HEK293 cells. In the most abundant SCN5A-Q1077del, late I Na for S1103Y alone was not significantly different from wild type (WT). However, late I Na for R680H, R680H+S1103Y (coexpressed), and R680H/S1103Y (on the same cDNA) was increased 2.1-, 3.4-, and 3.6-fold, respectively, compared with WT. Intracellular acidosis (pH 6.7) increased late I Na for S1103Y, R680H, R680H+S1103Y, and R680H/S1103Y by 2.2-, 2.4-, 5.0-, and 5.5-fold, respectively, compared with WT at pH 6.7. Expression in the less abundant SCN5A-Q1077 showed no increased late I Na . This is the initial report of a functional interaction for the common polymorphism S1103Y with another mutation in the major transcript Q1077del of SCN5A. The “double hit” and environmental factor of acidosis may have converged to cause arrhythmic sudden death in this case.

Abstract As the leading cause of mortality among gynecologic cancers, it is critical to increase understanding of ovarian cancer pathogenesis, which remains largely unknown. Several xenobiotic metabolizing enzymes are responsible for processing and inactivating carcinogens that could initiate ovarian carcinogenesis. Here, we hypothesize that single-nucleotide polymorphisms (SNPs) in genes encoding xenobiotic metabolizing enzymes may be associated with differential risk of ovarian cancer. Cases with epithelial ovarian cancer (N=930) and controls (N=1,037), frequency-matched on age and geographic residence, were enrolled at Mayo Clinic and Duke University, and genotyped at 163 tagSNPs in EPHX1, SULT1E1, ADH5, ADH4, ADH6, ADH1A, ADH1B, ADH1C, NQO2, NAT1, NAT2, GSTP1, CYP19A1, CYP1A1, CYP1A2, and NQO1 using an Illumina GoldenGate™ BeadArray array. Logistic regression was used to estimate odds ratios (ORs) and adjust for population structure and other potential confounders, including oral contraceptive use, parity, and family history. SNP-specific statistical analyses identified several noteworthy results including an association with increased risk of ovarian cancer with a SNP (rs2917666) in NAD(P)H dehydrogenase, quinone 1 (NQO1) (per-allele OR 1.16, 95% confidence interval (CI) 1.01-1.33, p=0.04). The SNP rs1051740 in epoxide hydrolase 1, microsomal (xenobiotic) (EPHX1) was suggestive of increased risk of invasive serous disease (TT v CT OR 0.85, 95% CI 0.66-1.09, TT v CC 1.29, 95% CI 0.89-1.88, p=0.09). In an effort to replicate these observations, a subset of 11 SNPs with a p-value < 0.10 were then genotyped in 727 invasive cancer cases and 1,065 controls from an Australian ovarian cancer study using a Sequenom iPlex assay. Results of combined analyses confirmed an association between EPHX1 rs1051740 and increased invasive serous ovarian cancer risk (TT v CT OR 0.99, 95% CI 0.77-1.29, TT v CC OR 1.61, 95% CI 1.23-2.11, p=0.001; recessive OR 1.61, 95% CI 1.25-2.09, p=0.001). This gene is involved in the activation and detoxification of tobacco-derived carcinogens, and smoking has been associated with the mucinous histologic subtype of ovarian cancer. Analyses by histological subtype and gene-environment interaction analyses considering genotype in conjunction with tobacco use and alcohol intake are underway. Due to the important role of EPHX1 in metabolizing pro-carcinogens and the observed association between rs1051740 and risk of invasive serous disease, an examination of this SNP in a larger ovarian cancer consortium is warranted. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 914.

Abstract The plasma cell malignancy Multiple Myeloma (MM) is a rare but deadly form of cancer with 5 year survival rates of ∼30%. The disease exacts an especially heavy burden on African American (AA) patients. In fact, African Americans are twice a likely to be diagnosed with and die from MM as compared to Caucasian Americans. Although socio-economic factors likely influence this disparity, the role of biology has not been ruled out. We have profiled ∼250 MM tumors for somatic copy number alterations using array-based Comparative Genomic Hybridization (aCGH) and Gene Expression Profiling as part of the Multiple Myeloma Genomics Initiative. To determine if somatic alterations may play a role in the disparity in incidence and/or severity of MM in AA, we compared the frequency of specific chromosomal aberrations in genes and genomic regions previously found to be involved in progression and poor outcome in MM among a cohort of one hundred ninety-six (196) patients including 16 African Americans and 180 Caucasians. The frequency of occurrence (expressed as a percentage) was determined for each of the following aberrations: 1p deletion, homozygous deletion of p18, chromosome 13 deletion, and chromosome 13 monosomy. No significant difference was detected in the frequency of chromosome 13 deletion and chromosome 13 monosomy between the two groups. However, significant differences were observed for chromosome 1p alterations. Homozygous deletion at the p18 locus at 1p occurred in 12.5% (2/16) of tumors from AA patients and 2.8% (5/180) of CA patient tumors (p = 0.045). We further stratified tumors by hyperdiploid or non-hyperdiploid status using a-CGH profiles to determine ploidy status. Most significantly, p18 homozygous deletion was found in 25% (2/8) of AA patients with non-hyperdiploid tumors and in only 1.2% (1/83) of CA patients with non-hyperdiploid tumors (p=3.2 × 10-4). A nominally significant difference among non-hyperdiploid patients was also present for overall 1p deletion, which was observed in 2/8 (25%) of AA non-hyperdiploid tumors and 33/83 (40%) of CA with non-hyperdiploid tumors (p=0.05). No differences were observed for 1p deletion or p18 homozygous deletion among hyperdiploid tumors between AA and CA patients. These results suggest that deletions at 1p are more common among African American MM patients. Furthermore, homozygous deletion encompassing the p18 locus is more significantly common among AA MM patients, especially AA patients with non-hyperdiploid tumors. As 1p deletion and p18 homozygous deletion have been linked to poor outcome, our results suggest that the increased frequency of these alterations in tumors from AA patients may in part explain the disparity in unfavorable outcomes seen among AA MM patients Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4822.

Abstract Microarray technologies are powerful assays, which can identify copy-number abnormalities (CNA) underlying the pathogenesis of cancer. Several commercial arrays are available but it is unclear which is the best platform. We did a side-by-side comparison between two leading arrays; the Affymetrix SNP6 and Agilent 1M, to compare data compression, noise, gene and exon coverage, and CNA detection. Five samples were run on both platforms and analyzed as recommended by the manufacturer. We first performed an in silico comparison to define the number of probes per serial 5k interval, number of probes per gene and exon, and the coefficient of variation of different smoothing windows. Comparing the CV of the two arrays showed a similar level of variation between a 3 and 5 probe averaging on the 1M and SNP6, respectively. Using these smoothing levels the 1M interrogates 81.2% of the genes in the genome compared to 69.3% on the SNP6. At the exon level the 1M has at least one probe in 64.8% compared to 41.2% on the SNP6. We observed a similar level of data compression (∼10%) on the two arrays but the SNP6 had nearly twice the noise (SD 0.38 versus 0.21). Finally, there was a marked increment in the number of CNA identified by 1M (mean of 78.5) than SNP6.0 (59.5). In this comparison the Agilent 1M out performed the Affymetrix SNP6. Even with half the number of probes, the 1M was superior in CNA detection, gene/exon coverage and showed less signal variation. A comparison with previous platforms showed that these two arrays did not identify new gene amplifications but did detect new deletions, however, neither platform detected several known deletions detected by other methods. Therefore, we designed a custom, exon-centered, 2×400K array (Agilent) with the goal of identifying additional deletions. The design outline was: a) all the probes from the Agilent CGH 44K array; b) 3 probes per exon across the human exome; c) high resolution tiling of 1450 cancer implicated genes; and d) tiling the 4kb flanking all MIRs. To improve performance, we only included probes with performance scores higher than 0.8 and 0.85 in queries b) and c), respectively. Lastly, 15000 probes from the 1M array that map to exons missed by our design parameters were also included. Our custom array has half the probes (415K) of the 1M (960K) and 4.5x less than the SNP6 (1.85M) but shows the best gene and exon coverage. When the minimum number of probes needed for calculating a CNA is considered, 86% of genes are interrogated compared to 81.2% (1M) and 69.3% (SNP6). The difference is even more marked at the exon level with 84% covered by at least one probe and at least 63.2% interrogated by two probes compared to 5.3% (1M) and 18.0% (SNP6). The promising in silico comparison of this exon-centered array, its more stringent design parameters in combination with significantly reducing the cost per run should make this a very promising array design for CNA analysis of tumor samples in the future Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4957.

Abstract Introduction: Alterations in components of the stromal tissue that underlie the epithelium can initiate, promote or inhibit epithelial tumorigenesis. Decorin (DCN) and lumican (LUM) are stromal genes with reduced expression in serous ovarian cancer. We hypothesized that single nucleotide polymorphisms (SNPs) in these genes may influence susceptibility to serous ovarian cancer. Methods: To test this hypothesis, we compared genotype frequencies of 11 tagSNPs in DCN and LUM between 397 Caucasian cases with primary serous ovarian cancer and 920 Caucasian controls in two studies conducted at Mayo Clinic and Duke University (discovery set). Associations were evaluated further in a third Caucasian population of 436 cases and 1,098 controls in Australia (replication set). TagSNPs were selected from unrelated Caucasian samples within HapMap based on the following criteria: (i) minor allele frequency ≥ 0.05, (ii) pairwise linkage disequilibrium (LD) of r2 ≥ 0.8, and (iii) location within, and 5kb upstream and downstream of, each gene region. Genotyping was performed using the Illumina GoldenGate™ assay and associations between SNPs and serous cancer were evaluated using unconditional logistic regression to estimate per allele odds ratios (OR) and 95% confidence intervals (95%CI). Untyped genotypes for DCN rs13312816 in the discovery set, and for DCN rs3138165 and LUM rs17018765 in the replication set, were imputed using the MACH software. Results: In the discovery set, we observed inverse associations between DCN rs3138165 (OR=0.7; 95%CI=0.5-1.0), DCN rs13312816 (OR=0.7; 95%CI=0.5-1.0), DCN rs516115 (OR=0.8; 95%CI=0.7-1.0) and LUM rs17018765 (OR=0.7; 95%CI=0.5-1.0) and risk of serous ovarian cancers (all Ptrend=0.06). Associations were confirmed in the replication set for DCN rs3138165 (OR=0.6; 95%CI=0.4-0.9; Ptrend=0.009), DCN rs13312816 (OR=0.7; 95%CI=0.5-0.9; Ptrend=0.01) and LUM rs17018765 (OR=0.6; 95%CI=0.4-0.9; Ptrend=0.008), but not for DCN rs516115 (Ptrend=0.20). To increase statistical power, data from the discovery and replication sets were combined (833 cases and 2,013 controls) following confirmation of no statistical heterogeneity in the ORs between study sites. In the combined sample, associations were strengthened for DCN rs3138165 (OR=0.7; 95%CI=0.5-0.9; Ptrend=0.002), DCN rs13312816 (OR=0.7; 95%CI=0.5-0.9; Ptrend=0.002), DCN rs516115 (OR=0.9; 95%CI=0.8-1.0; Ptrend=0.03) and LUM rs17018765 (OR=0.6; 95%CI=0.5-0.8; Ptrend=0.001). All four SNPs were in the same LD block on chromosome 12, suggesting that serous ovarian cancer susceptibility may be driven by a single, correlated variant in the region. Conclusion: The findings of this study suggest that genetic variation in DCN and LUM may influence susceptibility to serous ovarian cancer and contribute to the mounting evidence that supports the role of the stroma in epithelial ovarian cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2854.

Abstract There is increasing evidence that neighboring stromal cells are not uninvolved bystanders in the pathway to cancer. We hypothesized that SNPs in genes expressed as a consequence of interactions between ovarian cancer cells and the host micro-environment could contribute to ovarian cancer susceptibility. We therefore used a two-stage approach to comprehensively evaluate common single nucleotide polymorphisms (SNPs) in the Ovarian Cancer Association Consortium (OCAC) for 173 genes involved in stromal-epithelial interactions. Cases with epithelial ovarian cancer (n=675) and controls (n=1,162) were genotyped at 1536 SNPs using an Illumina GoldenGate™ BeadArray array. Logistic regression was used to estimate odds ratios (ORs) and adjust for potential confounders. Based on Positive Predictive Value estimates, three SNPs - PODXL rs1013368, ITGA6 rs13027811 and MMP3 rs522616 - were selected for replication using TaqMan genotyping in 3,734 serous invasive cases and 10,067 controls from 16 OCAC case-control studies. An additional 18 SNPs with Pper-allele <0.05 in the test set, and which fitted into an iPLEX design, were selected for replication by a subset of five OCAC studies (n=1771 serous invasive cases; n=4022 controls). The associations observed in the test set for the PODXL, ITGA6 and MMP3 SNPs were completely attenuated in the replication set (adj. Pper-allele ≥0.5). However, TERT rs7726159 showed evidence of a log additive association with ovarian cancer risk in the replication study (Pper-allele =0.03). Combined analysis of the test and replication sets for this SNP showed a significant association with risk of serous ovarian cancer among non-Hispanic whites [adj. ORper-allele 1.14 (1.04 - 1.24) p = 0.003]. A stronger association was observed for serous invasive cases when data for all ethnicities were included [adj. ORper-allele 1.18 (1.09 - 1.28) p = 2.46 × 10−5]. Stratification by histological subtype and malignant potential showed that TERT rs7726159 was also associated with risk of serous borderline tumors, but not with any other subtypes. Although TERT variants have not been previously reported to be associated with ovarian cancer, multiple genome-wide association studies have reported associations with this locus and risk of glioma, basal cell carcinoma, and several cancer types that are known to originate in the epithelium, including lung, bladder, prostate and cervical cancer. Further analysis of this locus is necessary to definitively identify the causal SNP(s). Our study adds to the growing evidence that, as well as 8q24, the TERT locus at 5p15.33, is a general cancer susceptibility locus. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4727.

Object Synovial cysts of the cervical spine are rare. Further, synovial cysts of the C1–2 articulation, or retroodontoid cysts, are very rare, with fewer than 20 cases reported overall. The authors report on a single-institution series of 10 patients with C1–2 retroodontoid synovial cysts. Methods The charts of 10 patients with pathologically confirmed synovial cysts following resection between January 1998 and June 2009 were reviewed. The clinical presentation, radiographic findings, surgical management, and pre- and postoperative functional levels (reported as a modified Rankin outcome) are reported. Results All 10 patients underwent attempts at complete resection of the synovial cyst; none of the lesions were simply aspirated. All 4 patients with an initial recommendation of observation alone ultimately underwent surgery because of their swift neurological deterioration. The mean age at surgery was 75.4 ± 4.6 years (range 54–81 years). The mean presenting cyst volume was 4.6 ± 1.7 cm3. Nine of 10 patients underwent transoral resection of the cyst with posterior fusion. Six of the 10 patients underwent additional posterior laminectomy for decompression. The hospital length of stay varied from 2 to 45 days, with a mean of 19 ± 7 days. All patients undergoing transoral decompression had varying degrees of difficulty with postoperative dysphagia, diagnosed using videofluoroscopy. All patients improved in their modified Rankin Scale score after surgical intervention with a mean follow-up of 42 months (95% CI 12–72 months). Conclusions Synovial cysts of the atlantoaxial joint are rare. They occur in older patients in whom clinical deterioration is likely to occur. In most cases, these cysts can be diagnosed preoperatively. Transoral decompression with posterior fusion is an effective treatment for C1–2 degenerative cysts and can be accomplished with few complications. However, the ideal treatment for these lesions remains unknown.

Abstract The molecular target(s) cooperating with proteasome inhibition in multiple myeloma (MM) remain unknown. We therefore measured proliferation in MM cells transfected with 13 984 small interfering RNAs in the absence or presence of increasing concentrations of bortezomib. We identified 37 genes, which when silenced, are not directly cytotoxic but do synergistically potentiate the growth inhibitory effects of bortezomib. To focus on bortezomib sensitizers, genes that also sensitized MM to melphalan were excluded. When suppressed, the strongest bortezomib sensitizers were the proteasome subunits PSMA5, PSMB2, PSMB3, and PSMB7 providing internal validation, but others included BAZ1B, CDK5, CDC42SE2, MDM4, NME7, RAB8B, TFE3, TNFAIP3, TNK1, TOP1, VAMP2, and YY1. The strongest hit CDK5 also featured prominently in pathway analysis of primary screen data. Cyclin-dependent kinase 5 (CDK5) is expressed at high levels in MM and neural tissues with relatively low expression in other organs. Viral shRNA knockdown of CDK5 consistently sensitized 5 genetically variable MM cell lines to proteasome inhibitors (bortezomib and carfilzomib). Small-molecule CDK5 inhibitors were demonstrated to synergize with bortezomib to induce cytotoxicity of primary myeloma cells and myeloma cell lines. CDK5 regulation of proteasome subunit PSMB5 was identified as a probable route to sensitization.

Background: Posterior tibial tendon dysfunction (PTTD) is a common malady leading to acquired flatfoot, which frequently causes foot and ankle pain and swelling. We hypothesized that patients with PTTD and pitting edema along the course of the posterior tibial tendon (PTT) would have evidence of fluid within the tendon sheath on MRI. We introduce and validate a novel, yet simple physical examination finding, the posterior tibial edema (PTE) sign, to help distinguish PTTD from other causes of foot and ankle pain and swelling. Patients and Methods: To determine an association between the PTE sign and changes to the PTT evident on MRI, we reviewed the medical records of patients with PTTD who underwent magnetic resonance imaging (MRI). Results: Of 186 patients identified with PTTD, 49 underwent MRI, and 42 (86%) demonstrated imaging characteristics consistent with tendonitis, tendinosis, or tenosynovitis. Presence or absence of increased posterior malleolar pitting edema agreed with presence or absence of these MRI findings in 43 patients (88%), making the clinical examination finding significantly predictive of MRI results ( p = 0.01). The sensitivity of the test for PTE was 86%, with specificity of 100%. Conclusion: The PTE sign refers to pitting edema along the course of the PTT, not associated with acute trauma and not accompanied by other areas of edema. Physical examination signs that are highly sensitive and specific to the condition may help lower the cost of diagnosis by eliminating the need for expensive tests that are not always necessary.

Object Little information is available on follow-up MR imaging after treatment of spinal dural arteriovenous fistulas (DAVFs). The authors studied MR imaging findings in treated spinal DAVFs in relation to clinical outcomes. Methods A retrospective review of patients with spinal DAVFs who had undergone both pre- and postoperative spinal MR imaging was conducted. Postoperative MR images were obtained as routine follow-up studies or because of subjective or objective clinical deterioration. Several pre- and posttreatment MR imaging characteristics were evaluated by 2 neuroradiologists blinded to the clinical outcome. Clinical outcomes of motor, sensory, and urinary function (in relation to the patient's preoperative status) at the time of the postoperative MR imaging were obtained from the clinical record. The chi-square, Fisher exact, and rank-sum tests were performed to correlate imaging findings and changes with clinical outcomes. Results Thirty-four patients met inclusion criteria. Treatment was surgical in 33 patients and endovascular in 1 patient. Follow-up MR imaging was performed at a mean 168 ± 107 days after treatment. Twenty-seven patients (79.4%) were either clinically stable or improved, and 7 (20.6%) experienced worsening in one or more clinical outcomes. Most patients were found to have improvement of MR imaging changes. However, some degree of persistent spinal cord signal abnormality, enhancement, and swelling was observed in 31 (91.2%), 29 (85.3%), and 18 (52.3%) patients, respectively. Changes in these MR imaging characteristics compared with preoperative MR imaging did not correlate with clinical outcomes (p > 0.05), with the one exception of a significant correlation between change in urinary function and extent of spinal cord contrast enhancement (p = 0.026), a correlation of uncertain importance. Ten of the 34 patients underwent posttreatment digital subtraction angiography, and 3 of these patients had recurrent/residual DAVFs. Worsening of motor function significantly correlated with recurrent/residual DAVF (p = 0.053). Conclusions Spinal cord abnormalities persist on postoperative MR imaging studies in patients with treated spinal DAVFs, and although they tend to mildly improve with time, these changes may not correlate with clinical outcomes. However, regardless of imaging findings, worsening motor function may correlate with a recurrent or residual DAVF.