Post hoc Analysis for Detecting Individual Rare Variant Risk Associations Using Probit Regression Bayesian Variable Selection Methods in Case‐Control Sequencing Studies
ABSTRACTRare variants (RVs) have been shown to be significant contributors to complex disease risk. By definition, these variants have very low minor allele frequencies and traditional single‐marker methods for statistical analysis are underpowered for typical sequencing study sample sizes. Multimarker burden‐type approaches attempt to identify aggregation of RVs across case‐control status by analyzing relatively small partitions of the genome, such as genes. However, it is generally the case that the aggregative measure would be a mixture of causal and neutral variants, and these omnibus tests do not directly provide any indication of which RVs may be driving a given association. Recently, Bayesian variable selection approaches have been proposed to identify RV associations from a large set of RVs under consideration. Although these approaches have been shown to be powerful at detecting associations at the RV level, there are often computational limitations on the total quantity of RVs under consideration and compromises are necessary for large‐scale application. Here, we propose a computationally efficient alternative formulation of this method using a probit regression approach specifically capable of simultaneously analyzing hundreds to thousands of RVs. We evaluate our approach to detect causal variation on simulated data and examine sensitivity and specificity in instances of high RV dimensionality as well as apply it to pathway‐level RV analysis results from a prostate cancer (PC) risk case‐control sequencing study. Finally, we discuss potential extensions and future directions of this work.
Assessing the role of insulin‐like growth factors and binding proteins in prostate cancer using Mendelian randomization: Genetic variants as instruments for circulating levels
Circulating insulin‐like growth factors (IGFs) and their binding proteins (IGFBPs) are associated with prostate cancer. Using genetic variants as instruments for IGF peptides, we investigated whether these associations are likely to be causal. We identified from the literature 56 single nucleotide polymorphisms (SNPs) in the IGF axis previously associated with biomarker levels (8 from a genome‐wide association study [GWAS] and 48 in reported candidate genes). In ∼700 men without prostate cancer and two replication cohorts (N ∼ 900 and ∼9,000), we examined the properties of these SNPS as instrumental variables (IVs) for IGF‐I, IGF‐II, IGFBP‐2 and IGFBP‐3. Those confirmed as strong IVs were tested for association with prostate cancer risk, low (< 7) vs. high (≥ 7) Gleason grade, localised vs. advanced stage, and mortality, in 22,936 controls and 22,992 cases. IV analysis was used in an attempt to estimate the causal effect of circulating IGF peptides on prostate cancer. Published SNPs in the IGFBP1/IGFBP3 gene region, particularly rs11977526, were strong instruments for IGF‐II and IGFBP‐3, less so for IGF‐I. Rs11977526 was associated with high (vs. low) Gleason grade (OR per IGF‐II/IGFBP‐3 level‐raising allele 1.05; 95% CI: 1.00, 1.10). Using rs11977526 as an IV we estimated the causal effect of a one SD increase in IGF‐II (∼265 ng/mL) on risk of high vs. low grade disease as 1.14 (95% CI: 1.00, 1.31). Because of the potential for pleiotropy of the genetic instruments, these findings can only causally implicate the IGF pathway in general, not any one specific biomarker.
Abstract P5-11-02: Survival benefit needed to undergo chemotherapy: Patients and physicians preferences
Abstract Background: Data regarding patients (pts) and physicians' preferences for modern adjuvant chemotherapy (CT) are limited. Prior studies suggested that most pts with early stage breast cancer were willing to receive 6 months of adjuvant cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) for modest survival benefits (e.g. most women would have accepted 3-6 months extension of life). Methods: E5103 was a phase III trial which randomized node positive or high risk node negative breast cancer pts to receive adjuvant CT (doxorubicin, cyclophosphamide and paclitaxel) with either placebo or bevacizumab. Telephone based surveys were administered to all pts enrolled on E5103 between 01/Jan/10 and 08/Jun/10, as part of a Decision-Making/Quality of Life component. Results presented here are part of the 18 months post-enrollment follow-up. Pts were asked to rate the survival benefit needed to justify 6 months of CT. A complementary survey was sent to all physicians who registered at least one pt on E5103. Results: 465 out of 519 eligible pts (90%) responded to this survey at 18 months. Main reasons for non response were: inability to reach the patient (6%) or patient refusal (2%). Median pts age was 51 (25-76); 42% of pts had at least a college degree. The majority had at least Stage II cancer. 179 (16%) physicians participated, among whom median age was 50 (35-70). The median years in practice was 17 (3-38); 78% of physicians worked on large size practices, 72% saw at least 5 new breast cancer pts/month, and 77% enroll between 1-4 pts on trials/month. We found considerable variation in pts preferences particularly for modest survival benefits: a substantial minority of pts (24%) would consider 6 months of CT definitely worthwhile for 1 month survival benefit, 18% would possibly consider it and 56% would not. The percentage considering CT definitely worthwhile increased with greater benefit, but did not reach 100%, even with 24 months survival benefit. About half of pts considered 6 months of CT definitely worthwhile for 9 months benefit, 70% for 12 months and 84% for 24 months. Physicians were less likely to accept CT for a small chance of benefit (34% of pts vs. 5% of physicians would definitely consider CT worthwhile for 2 months of benefit). For longer benefit, pts and physicians choices were similar (84% of pts vs. 92% of physicians would definitely consider CT worthwhile for 24 months benefit). Table Yes, definitely worthwhileYes, maybeNo, not worthwhileNo answerConsider 6 months of CT to live:PtsPhysiciansPtsPhysiciansPtsPhysiciansPts/Physicians*1 month longer24%3%18%15%56%80%2%2 months longer34%5%23%32%41%60%2%6 months longer44%32%35%54%19%12%2%9 months longer53%51%34%42%11%5%2%12 months longer70%75%23%22%5%1%2%24 months longer84%92%12%5%2%1%2%n Pts= 465; n Physicians= 179; * equal results in both groups Conclusions: This subgroup of pts who had undergone modern adjuvant CT in a large multicenter randomized controlled trial and these physicians who registered pts on the same trial had different cutoffs for acceptable levels of benefits and risks when considering adjuvant chemotherapy. It is important to engage pts in determining whether CT is or is not a "reasonable" option for treatment. Citation Format: Vaz Luis I, O'Neill A, Sepucha K, Miller KD, Baker E, Dang CT, Northfelt DW, Winer EP, Sledge GW, Schneider BP, Partridge A. Survival benefit needed to undergo chemotherapy: Patients and physicians preferences. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-11-02.
Intensive vs Standard Blood Pressure Control and Cardiovascular Disease Outcomes in Adults Aged ≥75 Years
ABSTRACT Introduction Penile prosthesis implantation has emerged as a definitive treatment to restore sexual function to the motivated man with erectile dysfunction. Substantial improvements in the design of inflatable devices have been made since they first became available more than four decades ago. Aim To review the history of the penile prosthesis, the indications, preoperative evaluation, and patient and partner satisfaction. The current approaches to addressing intra- and postoperative complications, provide an understanding of prosthesis infection, and placement of these devices will be reviewed. Methods A committee of worldwide experts in this field was assembled during the 2015 International Consultation on Sexual Medicine (ICSM) and performed a systematic review of the peer-reviewed published medical literature pertaining to penile prosthesis. Particular attention was given to higher level trials when available. Recommendations are based upon the Oxford Criteria. Main Outcome Measures Unfortunately there is limited level 1 and 2 evidence, and where expert opinion was utilized, the decision was unanimous within the committee with a goal of presenting a clinically relevant guideline pertaining to penile prostheses. Results Penile prosthesis has undergone an evolution over the past 40 years resulting in a more effective and reliable treatment for advanced erectile dysfunction not responding to less invasive methods including oral treatment with PDE5 inhibitors, vacuum erection device, and intracorporal injection therapy. It should be considered an appropriate treatment option for the man who wishes to restore erectile function and who understands the potential risk of mechanical failure and infection, both of which are less common now as a result of improvements made in device design as well as surgical protocols adhered to in the operating room. Patients must be clearly informed of the risks associated with penile prosthesis including mechanical failure, infection, shortening of the penis, change in sensation and configuration of the penis, as well as injury to local structures. Intraoperative complications are unusual but do occur and can usually be addressed intraoperatively to allow placement of the device at the time of initial surgery. Postoperative complications may also be addressed when they occur but may require more advanced reconstructive surgical techniques. Men with Peyronie's disease, corporal fibrosis due to infection, trauma, prior prosthesis explantation, priapism, and men who have undergone construction of a neophallus may require additional advanced maneuvers to obtain optimum results with a penile prosthesis. Conclusion Penile prosthesis remains as an important, viable, and effective treatment for male erectile dysfunction that does not respond to other less invasive approaches or when these approaches are contraindicated or not acceptable to the patient. These devices provide the patient with the ability to engage in penetrative sexual activity without interfering with urination, ejaculation, sensation, or orgasm. Although mechanical failure can occur, the current devices are more reliable as a result of design modifications. Infection remains the most dreaded complication but since the introduction of antibiotic and hydrophilic coatings, infection is less common. Overall, patient and partner satisfaction appear to be reasonably high when a penile prosthesis is used to restore erectile function.
ABSTRACT The health care-associated pneumonia (HCAP) criteria have a limited ability to predict pneumonia caused by drug-resistant bacteria and favor the overutilization of broad-spectrum antibiotics. We aimed to derive and validate a clinical prediction score with an improved ability to predict the risk of pneumonia due to drug-resistant pathogens compared to that of HCAP criteria. A derivation cohort of 200 microbiologically confirmed pneumonia cases in 2011 and 2012 was identified retrospectively. Risk factors for pneumonia due to drug-resistant pathogens were evaluated by logistic regression, and a novel prediction score (the drug resistance in pneumonia [DRIP] score) was derived. The score was then validated in a prospective, observational cohort of 200 microbiologically confirmed cases of pneumonia at four U.S. centers in 2013 and 2014. The DRIP score (area under the receiver operator curve [AUROC], 0.88 [95% confidence interval {CI}, 0.82 to 0.93]) performed significantly better ( P = 0.02) than the HCAP criteria (AUROC, 0.72 [95% CI, 0.64 to 0.79]). At a threshold of ≥4 points, the DRIP score demonstrated a sensitivity of 0.82 (95% CI, 0.67 to 0.88), a specificity of 0.81 (95% CI, 0.73 to 0.87), a positive predictive value (PPV) of 0.68 (95% CI, 0.56 to 0.78), and a negative predictive value (NPV) of 0.90 (95% CI, 0.81 to 0.93). By comparison, the performance of HCAP criteria was less favorable: sensitivity was 0.79 (95% CI, 0.67 to 0.88), specificity was 0.65 (95% CI, 0.56 to 0.73), PPV was 0.53 (95% CI, 0.42 to 0.63), and NPV was 0.86 (95% CI, 0.77 to 0.92). The overall accuracy of the HCAP criteria was 69.5% (95% CI, 62.5 to 75.7%), whereas that of the DRIP score was 81.5% (95% CI, 74.2 to 85.6%) ( P = 0.005). Unnecessary extended-spectrum antibiotics were recommended 46% less frequently by applying the DRIP score (25/200, 12.5%) than by use of HCAP criteria (47/200, 23.5%) ( P = 0.004), without increasing the rate at which inadequate treatment recommendations were made. The DRIP score was more predictive of the risk of pneumonia due to drug-resistant pathogens than HCAP criteria and may have the potential to decrease antibiotic overutilization in patients with pneumonia. Validation in larger cohorts of patients with pneumonia due to all causes is necessary.
A new HIF‐1α/RANTES‐driven pathway to hepatocellular carcinoma mediated by germline haploinsufficiency of SART1/HAF in mice
The hypoxia‐inducible factor (HIF), HIF‐1, is a central regulator of the response to low oxygen or inflammatory stress and plays an essential role in survival and function of immune cells. However, the mechanisms regulating nonhypoxic induction of HIF‐1 remain unclear. Here, we assess the impact of germline heterozygosity of a novel, oxygen‐independent ubiquitin ligase for HIF‐1α: hypoxia‐associated factor (HAF; encoded by SART1). SART1−/− mice were embryonic lethal, whereas male SART1+/− mice spontaneously recapitulated key features of nonalcoholic steatohepatitis (NASH)‐driven hepatocellular carcinoma (HCC), including steatosis, fibrosis, and inflammatory cytokine production. Male, but not female, SART1+/− mice showed significant up‐regulation of HIF‐1α in circulating and liver‐infiltrating immune cells, but not in hepatocytes, before development of malignancy. Additionally, Kupffer cells derived from male, but not female, SART1+/− mice produced increased levels of the HIF‐1‐dependent chemokine, regulated on activation, normal T‐cell expressed and secreted (RANTES), compared to wild type. This was associated with increased liver‐neutrophilic infiltration, whereas infiltration of lymphocytes and macrophages were not significantly different. Neutralization of circulating RANTES decreased liver neutrophilic infiltration and attenuated HCC tumor initiation/growth in SART1+/− mice. Conclusion: This work establishes a new tumor‐suppressor role for HAF in immune cell function by preventing inappropriate HIF‐1 activation in male mice and identifies RANTES as a novel therapeutic target for NASH and NASH‐driven HCC. (Hepatology 2016;63:1576‐1591)