How well do polygenic risk scores identify men at high risk for prostate cancer? Systematic review and meta-analysis

OBJECTIVES

Genome-wide association studies have revealed over 200 genetic susceptibility loci for prostate cancer (PCa). By combining them, polygenic risk scores (PRS) can be generated to predict risk of PCa. We summarize the published evidence and conduct meta-analyses of PRS as a predictor of PCa risk in Caucasian men.

PATIENTS AND METHODS

Data were extracted from 59 studies, with 16 studies including 17 separate analyses used in the main meta-analysis with a total of 20,786 cases and 69,106 controls identified through a systematic search of ten databases. Random effects meta-analysis was used to obtain pooled estimates of area under the receiver-operating characteristic curve (AUC). Meta-regression was used to assess the impact of number of single-nucleotide polymorphisms (SNPs) incorporated in PRS on AUC. Heterogeneity is expressed as I² scores. Publication bias was evaluated using funnel plots and Egger tests.

RESULTS

The ability of PRS to identify men with PCa was modest (pooled AUC 0.63, 95% CI 0.62-0.64) with moderate consistency (I² 64%). Combining PRS with clinical variables increased the pooled AUC to 0.74 (0.68-0.81). Meta-regression showed only negligible increase in AUC for adding incremental SNPs. Despite moderate heterogeneity, publication bias was not evident.

CONCLUSION

Typically, PRS accuracy is comparable to PSA or family history with a pooled AUC value 0.63 indicating mediocre performance for PRS alone.

Clinicopathological characteristics of high-altitude polycythemia-related kidney disease in Tibetan inhabitants

High-altitude polycythemia (HAPC) is a clinical syndrome that occurs in native inhabitants or long-term residents living at altitude. The kidney is one of the most affected organs. However, the clinical and kidney histopathological profiles of HAPC-related kidney disease have rarely been reported. Here, we report kidney biopsy-based clinicopathological study on this disease. HAPC was defined as excessive erythrocytosis [females, hemoglobin 190 g/L or more; males, 210 g/L or more] in patients living above an altitude of 2500 m for more than ten years. A total of 416 Tibetan patients underwent kidney biopsy between January 1, 2016, and November 31, 2020. Of these patients 17 met the diagnostic criteria for HAPC-related kidney disease. Clinically, these patients had a median urinary protein level of 2.5 g/24-hour (range 1.81-6.85). Twelve patients had hyperuricemia, nine had hypertension, and three had kidney insufficiency. On histopathology, glomerular hypertrophy, glomerular basement membrane thickening, podocyte foot process effacement, segmental glomerulosclerosis and global glomerulosclerosis were the main features. Extraglomerular arterial/arteriolar lesions were common, presenting as intimal fibrosis, hyalinosis and endothelial cell swelling/subintimal edema. Expansion of the arterial/arteriolar medial wall area characterized by smooth muscle cell proliferation was clearly observed, potentially indicating vascular remodeling. Hypoxia-inducible factor 2α was expressed in the kidney tissues of these patients. Thus, the pathological changes of HAPC-related kidney disease encompassed both glomerular and extraglomerular vascular lesions, suggesting a key role of both chronic hypoxia itself and secondary hemodynamic changes in the pathogenesis of this disease.

A review of the microtremor horizontal-to-vertical spectral ratio (MHVSR) method

The single-station microtremor horizontal-to-vertical spectral ratio (MHVSR) method was initially proposed to retrieve the site amplification function and its resonance frequencies produced by unconsolidated sediments overlying high-velocity bedrock. Presently, MHVSR measurements are predominantly conducted to obtain an estimate of the fundamental site frequency at sites where a strong subsurface impedance contrast exists. Of the earthquake site characterization methods presented in this special issue, the MHVSR method is the furthest behind in terms of consensus towards standardized guidelines and commercial use. The greatest challenges to an international standardization of MHVSR acquisition and analysis are (1) the what - the underlying composition of the microtremor wavefield is site-dependent, and thus, the appropriate theoretical (forward) model for inversion is still debated; and (2) the how - many factors and options are involved in the data acquisition, processing, and interpretation stages. This paper reviews briefly a historical development of the MHVSR technique and the physical basis of an MHVSR (the what). We then summarize recommendations for MHVSR acquisition and analysis (the how). Specific sections address MHVSR interpretation and uncertainty assessment.

Size of low wall shear stress areas in coronary arteries is related to epicardial physiology and not to microcirculatory resistance

Background

Wall shear stress (WSS) plays an important role in coronary atherosclerosis. Low WSS is associated with inflammation, endothelial dysfunction, and progression of atherosclerosis; while high WSS leads to vulnerable plaque transformation and future myocardial infarction. Defining the relationship between WSS and the currently available coronary physiology indices would provide valuable insights into potential mechanisms for predicting future adverse cardiac events.

Purpose

To investigate the relationship between WSS and the coronary epicardial/microvascular physiology indices.

Methods

Patients undergoing coronary angiography and physiology testing were prospectively recruited. Physiology measurements were performed under resting and hyperaemic conditions using a pressure/temperature sensor guidewire. Fractional flow reserve (FFR), non-hyperaemic pressure ratios (NHPRs), coronary flow reserve (CFR), and corrected index of microcirculatory resistance (IMR) were measured. The NHPRs including resting full-cycle ratio (RFR), resting distal/aortic pressure (Pd/Pa), instantaneous wave-free ratio (iFR), diastolic pressure ratio (dPR) and diastolic hyperaemia-free ratio (DFR) were derived offline by a blinded expert reader. Values of FFR ≤0.80, NHPR ≤0.89, CFR <2, or IMR >25 were considered ischaemic/abnormal. Computational fluid dynamics analysis was performed and fluid motion equations were solved using finite-volume based software. The inlet and outlet boundary conditions were set to the patient-specific Pa and Pd respectively. The lesion WSS, mean WSS in five segments (WSSupstream = 5mm proximal to lesion, WSSprox = proximal third of lesion, WSSmid = middle third of lesion, WSSdistal = distal third of lesion, WSSdownstream = 5mm distal to lesion), and the total area of low WSS (defined as <1 Pa) along the entire vessel were calculated (Figure A).

Results

A total of 112 vessels from 93 patients were included in the study. The total area of low WSS was significantly larger in lesions with ischaemic FFR, NHPRs, and CFR values (Figure B), and not significantly different in lesions with abnormal IMR values. There was no significant difference in lesion WSS between groups stratified by all physiology indices. Within the lesion WSS sub-segments, WSSprox was significant higher in ischaemic lesions stratified by normal/abnormal FFR, iFR, and dPR (4.2 vs 3.3 Pa, 4.2 vs 3.3 Pa, 4.3 vs 3.3 Pa respectively, all p=0.04), and not significantly different when stratified by RFR, DFR, Pd/Pa, CFR, and IMR.

Conclusion

Functionally significant coronary lesions classified by the epicardial physiology indices have significantly larger total area of low WSS and higher WSSprox which may explain the higher cardiovascular event rates in patients with ischaemic lesions. There was no significant relationship between WSS and coronary microcirculatory resistance.

Figure 1

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): National Heart Foundation of Australia Health Professional Scholarship

A real-world comparison of outcomes between fractional flow reserve-guided versus angiography-guided percutaneous coronary intervention

Background

Fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) has been shown to be superior to angiography-guided PCI in randomized controlled studies. However, real-world data on the use and outcomes of FFR-guided PCI remain limited.

Purpose

To investigate the outcomes of patients undergoing FFR-guided PCI compared to angiography-guided PCI in a large, state-wide unselected cohort.

Methods

All patients undergoing PCI between June 2017 and June 2018 recorded by the Centre for Health Record Linkage (CHeReL) were included in the study. The CHeReL database is one of the largest data linkage systems in Australia, capturing health data from ≥97% of all healthcare facilities in the state of New South Wales, which has a population of 7.5 million people. The PCI cohort was stratified into the FFR-guided group when a concomitant FFR procedure was performed, and the angiography-guided group when no FFR was performed. The primary endpoint was a combined endpoint of death or myocardial infarction (MI). Secondary endpoints included all-cause death, cardiovascular (CV) death, and MI.

Results

The cohort comprised 10,304 patients, of which 542 (5%) underwent FFR-guided PCI. There were no significant differences in age, gender, or comorbidities between the two groups. During a mean follow-up of 12±4 months, the FFR-guided PCI group had reduced occurrence of the primary endpoint (3% vs 8%, P<0.001), all-cause death (1% vs 4%, P=0.001), CV death (1% vs 3%, P=0.01), and MI (2% vs 4%, P=0.01) (Figure). Multivariable Cox regression analysis demonstrated FFR-guidance to be an independent predictor of the primary endpoint (hazard ratio [HR] 0.47, 95% confidence interval [CI] 0.28–0.78, P=0.004), after adjusting for age, clinical presentation, comorbidities, and multi-vessel PCI. A sensitivity analysis was performed excluding patients that presented with acute MI, leading to a smaller cohort of 5,850 patients, of which 448 (8%) underwent FFR-guided PCI. FFR-guidance remained an independent predictor of the primary endpoint in this cohort of stable patients (HR 0.36, 95% CI 0.17–0.77, P=0.01).

Conclusion

In this real-world study of patients undergoing PCI, FFR-guidance was associated with improved clinical outcomes, driven by the lower hard endpoint of death or MI. The use of FFR-guided PCI remains limited worldwide, and efforts should be directed to increase adoption of this technique in future.

Figure 1

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): National Heart Foundation of Australia Health Professional Scholarship

Abstract P6-20-04: Activation of AR inhibits growth of endocrine-resistant breast cancer

Introduction

Resistance to endocrine therapy is a major clinical problem in estrogen receptor positive (ER+) breast cancer. The androgen receptor (AR) is expressed in ˜90% of all ER+ breast cancers and high expression of AR is associated with a better patient outcome in this subtype. In agreement, AR activation in breast cancer cell line models reduces proliferation of cells via antagonism of ER signaling. However, uncertainty surrounding the role of AR in endocrine resistance is reflected in current clinical trials in which both AR agonists and antagonists are being investigated. In this study, we sought to investigate the optimal approach in targeting AR in endocrine-resistant breast cancer.

Methods

We evaluated the consequences of AR activation, using AR cognate ligand 5α-dihydrotestosterone (DHT) and selective AR modulator enobosarm, and AR antagonism using enzalutamide on in vitro and in vivo models of endocrine-resistance. The efficacy of these AR modulators were assessed in vitro using tamoxifen-resistant (TamR) and long-term estrogen derived (LTED) models of MCF7 cells, and in vivo using ESR1 mutant E2-dependent (HCI-005) and ESR1 wild-type E2-independent (Gar15-13) endocrine-resistant PDX models

Results

Treatment with DHT and enobosarm inhibited the growth of MCF7 TamR and LTED cells but enzalutamide had no effect. AR activation was associated with loss of ER in MCF7 TamR cells and loss of ER-regulated PR expression in MCF7 LTED which suggests that this growth suppression was mediated through the antagonism of ER signaling. Notably, an additive anti-proliferative effect was observed with the combination of enobosarm and CDK4/6 inhibitor palbocilib in the MCF7 TamR cells. A similar pattern was observed in vivo with DHT strongly inhibiting the proliferation of both PDX models. Enobosarm similarly suppressed the proliferation of HCI-005, and to a lesser extent in Gar15-13. The benefit of enobosarm in Gar15-13 was significant given that this model is fulvestrant-resistant. Antagonizing AR with enzalutamide had no effect on growth of Gar15-13 model, similar to our in vitro data. AR agonists reduced expression levels of ER and PR in HCI-005, and transcriptomic analysis of AR agonist-treated Gar15-13 identified significant negative enrichment of genes related to proliferation and estrogen response. These observations indicate that the growth-suppressive effects of AR activation in vivo were mediated through inhibiting ER signaling. We identified an AR gene signature, through RNA-seq analysis of DHT-treated Gar15-13 PDX, which is strongly associated with good outcome in the METABRIC dataset, supporting the hypothesis that an active canonical AR signaling is tumor suppressive in both endocrine-sensitive and -resistant disease contexts. Lastly, we present in vivo data demonstrating enhanced suppression of Ki-67 with the combination of enobosarm and palbociclib in the Gar15-13 PDX.

Conclusion

We have demonstrated that activating AR is an effective therapeutic approach in endocrine-resistant breast cancer, and the combination of an AR agonist with a CDK4/6 inhibitor warrants further investigation in this breast cancer subtype.

Citation Format: Chia KM, Milioli H, Portman N, Laven-Law G, Yong A, Swarbrick A, Caldon L, Tilley W, Hickey T, Lim E. Activation of AR inhibits growth of endocrine-resistant breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-20-04.

The incidence, mortality and timing of Pneumocystis jiroveci pneumonia after hematopoietic cell transplantation: a CIBMTR analysis

Pneumocystis jiroveci pneumonia (PJP) is associated with high morbidity and mortality after hematopoietic stem cell transplantation (HSCT). Little is known about PJP infections after HSCT because of the rarity of disease given routine prophylaxis. We report the results of a Center for International Blood and Marrow Transplant Research study evaluating the incidence, timing, prophylaxis agents, risk factors and mortality of PJP after autologous (auto) and allogeneic (allo) HSCT. Between 1995 and 2005, 0.63% allo recipients and 0.28% auto recipients of first HSCT developed PJP. Cases occurred as early as 30 days to beyond a year after allo HSCT. A nested case cohort analysis with supplemental data (n=68 allo cases, n=111 allo controls) revealed that risk factors for PJP infection included lymphopenia and mismatch after HSCT. After allo or auto HSCT, overall survival was significantly poorer among cases vs controls (P=0.0004). After controlling for significant variables, the proportional hazards model revealed that PJP cases were 6.87 times more likely to die vs matched controls (P<0.0001). We conclude PJP infection is rare after HSCT but is associated with high mortality. Factors associated with GVHD and with poor immune reconstitution are among the risk factors for PJP and suggest that protracted prophylaxis for PJP in high-risk HSCT recipients may improve outcomes.

Validation of the Vitiligo Noticeability Scale: a patient-reported outcome measure of vitiligo treatment success

BACKGROUND

Patient-reported outcome measures are rarely used in vitiligo trials. The Vitiligo Noticeability Scale (VNS) is a new patient-reported outcome measure assessing how 'noticeable' vitiligo patches are after treatment. The noticeability of vitiligo after treatment is an important indicator of treatment success from the patient's perspective.

OBJECTIVES

To evaluate the construct validity, acceptability and interpretability of the VNS.

METHODS

Clinicians (n = 33) and patients with vitiligo (n = 101) examined 39 image pairs, each depicting a vitiligo lesion pre- and post-treatment. Using an online questionnaire, respondents gave a global assessment of treatment success and a VNS score for treatment response. Clinicians also estimated percentage repigmentation of lesions (< 25%; 25-50%; 51-75%; > 75%). Treatment success was defined as 'yes' on global assessment, a VNS score of 4 or 5, and > 75% repigmentation. Agreement between respondents and the different scales was assessed using kappa (κ) statistics.

RESULTS

Vitiligo Noticeability Scale scores were associated with both patient- and clinician-reported global treatment success (κ = 0·54 and κ = 0·47, respectively). Percentage repigmentation showed a weaker association with patient- and clinician-reported global treatment success (κ = 0·39 and κ = 0·29, respectively). VNS scores of 4 or 5 can be interpreted as representing treatment success. Images depicting post-treatment hyperpigmentation were less likely to be rated as successful.

CONCLUSIONS

The VNS is a valid patient-reported measure of vitiligo treatment success. Further validation of the VNS is required, using larger sets of clinical pre- and post-treatment images, affecting a wider range of anatomical sites.

Secondary solid cancer screening following hematopoietic cell transplantation

Hematopoietic stem cell transplant (HCT) recipients have a substantial risk of developing secondary solid cancers, particularly beyond 5 years after HCT and without reaching a plateau overtime. A working group was established through the Center for International Blood and Marrow Transplant Research and the European Group for Blood and Marrow Transplantation with the goal to facilitate implementation of cancer screening appropriate to HCT recipients. The working group reviewed guidelines and methods for cancer screening applicable to the general population and reviewed the incidence and risk factors for secondary cancers after HCT. A consensus approach was used to establish recommendations for individual secondary cancers. The most common sites include oral cavity, skin, breast and thyroid. Risks of cancers are increased after HCT compared with the general population in skin, thyroid, oral cavity, esophagus, liver, nervous system, bone and connective tissues. Myeloablative TBI, young age at HCT, chronic GVHD and prolonged immunosuppressive treatment beyond 24 months were well-documented risk factors for many types of secondary cancers. All HCT recipients should be advised of the risks of secondary cancers annually and encouraged to undergo recommended screening based on their predisposition. Here we propose guidelines to help clinicians in providing screening and preventive care for secondary cancers among HCT recipients.

Advanced glycation end products in foods and a practical guide to their reduction in the diet

Modern diets are largely heat-processed and as a result contain high levels of advanced glycation end products (AGEs). Dietary advanced glycation end products (dAGEs) are known to contribute to increased oxidant stress and inflammation, which are linked to the recent epidemics of diabetes and cardiovascular disease. This report significantly expands the available dAGE database, validates the dAGE testing methodology, compares cooking procedures and inhibitory agents on new dAGE formation, and introduces practical approaches for reducing dAGE consumption in daily life. Based on the findings, dry heat promotes new dAGE formation by >10- to 100-fold above the uncooked state across food categories. Animal-derived foods that are high in fat and protein are generally AGE-rich and prone to new AGE formation during cooking. In contrast, carbohydrate-rich foods such as vegetables, fruits, whole grains, and milk contain relatively few AGEs, even after cooking. The formation of new dAGEs during cooking was prevented by the AGE inhibitory compound aminoguanidine and significantly reduced by cooking with moist heat, using shorter cooking times, cooking at lower temperatures, and by use of acidic ingredients such as lemon juice or vinegar. The new dAGE database provides a valuable instrument for estimating dAGE intake and for guiding food choices to reduce dAGE intake.

Protection against loss of innate defenses in adulthood by low advanced glycation end products (AGE) intake: role of the antiinflammatory AGE receptor-1

CONTEXT

Increased oxidant stress and inflammation (OS/infl) are linked to both aging-related diseases and advanced glycation end products (AGEs). Whereas AGE receptor-1 (AGER1) reduces OS/infl in animals, this has not been assessed in normal humans.

OBJECTIVE

The objectives of the study were to determine whether AGER1 correlates with AGEs and OS/infl and a reduction of dietary AGEs (dAGEs) lowers OS/infl in healthy adults and chronic kidney disease (CKD-3) patients.

DESIGN

This study was cross-sectional with 2-yr follow-up studies of healthy adults and CKD-3 patients, a subset of which received a reduced AGE or regular diet.

SETTING

The study was conducted at general community and renal clinics.

PARTICIPANTS

Participants included 325 healthy adults (18-45 and >60 yr old) and 66 CKD-3 patients.

INTERVENTION

An isocaloric low-AGE (30-50% reduction) or regular diet was given to 40 healthy subjects for 4 months and to nine CKD-3 patients for 4 wk.

MAIN OUTCOME

Relationships between age, dAGEs, serum AGEs, peripheral mononuclear cell AGE-receptors, and OS/Infl before and after reduction of dAGE intake were measured.

RESULTS

AGEs, oxidant stress, receptor for AGE, and TNFalpha were reduced in normal and CKD-3 patients after the low-AGE diet, independently of age. AGER1 levels in CKD-3 patients on the low-AGE diet resembled 18- to 45-yr-old normal subjects. Dietary, serum, and urine AGEs correlated positively with peripheral mononuclear cell AGER1 levels in healthy participants. AGER1 was suppressed in CKD-3 subjects, whereas receptor for AGE and TNFalpha were increased.

CONCLUSIONS

Reduction of AGEs in normal diets may lower oxidant stress/inflammation and restore levels of AGER1, an antioxidant, in healthy and aging subjects and CKD-3 patients. AGE intake has implications for health outcomes and costs and warrants further testing.