Robustness of cancer microbiome signals over a broad range of methodological variation

In 2020, we identified cancer-specific microbial signals in The Cancer Genome Atlas (TCGA) [1]. Multiple peer-reviewed papers independently verified or extended our findings [2-12]. Given this impact, we carefully considered concerns by Gihawi et al. [13] that batch correction and database contamination with host sequences artificially created the appearance of cancer type-specific microbiomes. (1) We tested batch correction by comparing raw and Voom-SNM-corrected data per-batch, finding predictive equivalence and significantly similar features. We found consistent results with a modern microbiome-specific method (ConQuR [14]), and when restricting to taxa found in an independent, highly-decontaminated cohort. (2) Using Conterminator [15], we found low levels of human contamination in our original databases (~1% of genomes). We demonstrated that the increased detection of human reads in Gihawi et al. [13] was due to using a newer human genome reference. (3) We developed Exhaustive, a method twice as sensitive as Conterminator, to clean RefSeq. We comprehensively host-deplete TCGA with many human (pan)genome references. We repeated all analyses with this and the Gihawi et al. [13] pipeline, and found cancer type-specific microbiomes. These extensive re-analyses and updated methods validate our original conclusion that cancer type-specific microbial signatures exist in TCGA, and show they are robust to methodology.

Effect of Cobalt-60 Treatment Dose Rate on Arteriovenous Malformation Obliteration After Stereotactic Radiosurgery With Gamma Knife

BACKGROUND AND OBJECTIVES

Stereotactic radiosurgery (SRS) marginal dose is associated with successful obliteration of cerebral arteriovenous malformations (AVM). SRS dose rate-how old the cobalt-60 sources are-is known to influence outcomes for some neurological conditions and benign tumors. The objective of this study was to determine the association between cobalt-60 treatment dose rate and cerebral AVM obliteration in patients treated with SRS.

METHODS

We performed a retrospective cohort study of 361 patients undergoing 411 AVM-directed SRS treatments between 2005 and 2019 at a single institution. Lesion characteristics, SRS details, obliteration dates, and post-treatment toxicities were recorded. Univariate and multivariate regression analyses of AVM outcomes regarding SRS dose rate (range 1.3-3.7 Gy, mean = 2.4 Gy, median = 2.5 Gy) were performed.

RESULTS

At 10 years post-SRS, 68% of AVMs were obliterated on follow-up imaging. Dose rates >2.9 Gy/min were found to be significantly associated with AVM obliteration compared with those <2.1 Gy/min ( P = .034). AVM size, biologically effective dose, and SRS marginal dose were also associated with obliteration, with obliteration more likely for smaller lesions, higher biologically effective dose, and higher marginal dose. Higher dose rates were not associated with the development of post-SRS radiological or symptomatic edema, although larger AVM volume was associated with both types of edema.

CONCLUSION

Patients with cerebral AVMs treated with higher SRS dose rates (from newer cobalt-60 sources) experience higher incidences of obliteration without a significant change in the risk of post-treatment edema.

On dosimetric characteristics of detectors for relative dosimetry in small fields: a multicenter experimental study

Objective. In this multicentric collaborative study, we aimed to verify whether the selected radiation detectors satisfy the requirements of TRS-483 Code of Practice for relative small field dosimetry in megavoltage photon beams used in radiotherapy, by investigating four dosimetric characteristics. Furthermore, we intended to analyze and complement the recommendations given in TRS-483.Approach. Short-term stability, dose linearity, dose-rate dependence, and leakage were determined for 17 models of detectors considered suitable for small field dosimetry. Altogether, 47 detectors were used in this study across ten institutions. Photon beams with 6 and 10 MV, with and without flattening filters, generated by Elekta Versa HDTMor Varian TrueBeamTMlinear accelerators, were used.Main results. The tolerance level of 0.1% for stability was fulfilled by 70% of the data points. For the determination of dose linearity, two methods were considered. Results from the use of a stricter method show that the guideline of 0.1% for dose linearity is not attainable for most of the detectors used in the study. Following the second approach (squared Pearson's correlation coefficientr2), it was found that 100% of the data fulfill the criteriar2> 0.999 (0.1% guideline for tolerance). Less than 50% of all data points satisfied the published tolerance of 0.1% for dose-rate dependence. Almost all data points (98.2%) satisfied the 0.1% criterion for leakage.Significance. For short-term stability (repeatability), it was found that the 0.1% guideline could not be met. Therefore, a less rigorous criterion of 0.25% is proposed. For dose linearity, our recommendation is to adopt a simple and clear methodology and to define an achievable tolerance based on the experimental data. For dose-rate dependence, a realistic criterion of 1% is proposed instead of the present 0.1%. Agreement was found with published guidelines for background signal (leakage).

Altered expression of the L-arginine/nitric oxide pathway in ovarian cancer: metabolic biomarkers and biological implications

MOTIVATION

Ovarian cancer (OC) is a highly lethal gynecological malignancy. Extensive research has shown that OC cells undergo significant metabolic alterations during tumorigenesis. In this study, we aim to leverage these metabolic changes as potential biomarkers for assessing ovarian cancer.

METHODS

A functional module-based approach was utilized to identify key gene expression pathways that distinguish different stages of ovarian cancer (OC) within a tissue biopsy cohort. This cohort consisted of control samples (n = 79), stage I/II samples (n = 280), and stage III/IV samples (n = 1016). To further explore these altered molecular pathways, minimal spanning tree (MST) analysis was applied, leading to the formulation of metabolic biomarker hypotheses for OC liquid biopsy. To validate, a multiple reaction monitoring (MRM) based quantitative LCMS/MS method was developed. This method allowed for the precise quantification of targeted metabolite biomarkers using an OC blood cohort comprising control samples (n = 464), benign samples (n = 3), and OC samples (n = 13).

RESULTS

Eleven functional modules were identified as significant differentiators (false discovery rate, FDR < 0.05) between normal and early-stage, or early-stage and late-stage ovarian cancer (OC) tumor tissues. MST analysis revealed that the metabolic L-arginine/nitric oxide (L-ARG/NO) pathway was reprogrammed, and the modules related to "DNA replication" and "DNA repair and recombination" served as anchor modules connecting the other nine modules. Based on this analysis, symmetric dimethylarginine (SDMA) and arginine were proposed as potential liquid biopsy biomarkers for OC assessment. Our quantitative LCMS/MS analysis on our OC blood cohort provided direct evidence supporting the use of the SDMA-to-arginine ratio as a liquid biopsy panel to distinguish between normal and OC samples, with an area under the ROC curve (AUC) of 98.3%.

CONCLUSION

Our comprehensive analysis of tissue genomics and blood quantitative LC/MSMS metabolic data shed light on the metabolic reprogramming underlying OC pathophysiology. These findings offer new insights into the potential diagnostic utility of the SDMA-to-arginine ratio for OC assessment. Further validation studies using adequately powered OC cohorts are warranted to fully establish the clinical effectiveness of this diagnostic test.

Development and Validation of Blood-Based Predictive Biomarkers for Response to PD-1/PD-L1 Checkpoint Inhibitors: Evidence of a Universal Systemic Core of 3D Immunogenetic Profiling across Multiple Oncological Indications

BACKGROUND

Unprecedented advantages in cancer treatment with immune checkpoint inhibitors (ICIs) remain limited to only a subset of patients. Systemic analyses of the regulatory 3D genome architecture linked to individual epigenetic and immunogenetic controls associated with tumour immune evasion mechanisms and immune checkpoint pathways reveal a highly prevalent molecular profile predictive of response to PD-1/PD-L1 ICIs. A clinical blood test based on a set of eight (8) 3D genomic biomarkers has been developed and validated on the basis of an observational trial to predict response to ICI therapy.

METHODS

The predictive eight biomarker set is derived from prospective observational clinical trials, representing 280 treatments with Pembrolizumab, Atezolizumab, Durvalumab, Nivolumab, and Avelumab in a broad range of indications: melanoma, lung, hepatocellular, renal, breast, bladder, colon, head and neck, bone, brain, lymphoma, prostate, vulvar, and cervical cancers.

RESULTS

The 3D genomic eight biomarker panel for response to immune checkpoint therapy achieved a high accuracy of 85%, sensitivity of 93%, and specificity of 82%.

CONCLUSIONS

This study demonstrates that a 3D genomic approach can be used to develop a predictive clinical assay for response to PD-1/PD-L1 checkpoint inhibition in cancer patients.

Dosimetric evaluation of adult and paediatric brain tumours planned using mask-based cobalt-60 fractionated stereotactic radiotherapy compared to linear accelerator-based volumetric modulated arc therapy

INTRODUCTION

We conducted a study to evaluate the dosimetric feasibility of mask-based cobalt-60 fractionated stereotactic radiotherapy (mcfSRT) with the Leksell Gamma Knife® Icon™ device.

METHODS

Eleven patients with intracranial tumours were selected for this dosimetry study. These patients, previously treated with volumetric arc therapy (VMAT), were re-planned using mcfSRT. Target volume coverage, conformity/gradient indices, doses to organs at risk and treatment times were compared between the mcfSRT and VMAT plans. Two-sided paired Wilcoxon signed-rank test was used to compare differences between the two plans.

RESULTS

The V95 for PTV was similar between fractionated mcfSRT and VMAT (P = 0.47). The conformity index and gradient indices were 0.9 and 3.3, respectively, for mcfSRT compared to 0.7 and 4.2, respectively, for VMAT (P < 0.001 and 0.004, respectively). The radiation exposure to normal brain was lower for mcfSRT across V10, V25 and V50 compared with VMAT (P = 0.007, <0.001 and <0.001, respectively). The median D0.1cc for optic nerve and chiasm as well as the median D50 to the hippocampi were lower for mcfSRT compared to VMAT. Median beam-on time for mcfSRT was 9.7 min per fraction, compared to 0.9 min for VMAT (P = 0.002).

CONCLUSION

mcfSRT plans achieve equivalent target volume coverage, improved conformity and gradient indices, and reduced radiation doses to organs at risk as compared with VMAT plans. These results suggest superior dosimetric parameters for mcfSRT plans and can form the basis for future prospective studies.

Proteomic profiling of antibody-drug conjugate (ADC) biomarkers in pancreatic cancer

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Background: Pancreatic cancer (PaC) is a highly fatal disease with a 5-year survival rate of 5-10%. Effective screening is not available, and most patients (50-55%) present with metastatic (50%-55%) disease at diagnosis. For patients with advanced PaC, the standard chemotherapy combinations include FOLFIRINOX and/or gemcitabine/nab-paclitaxel which has results in a overall survival of 7-11 months. The lack of effective therapies underscores the importance of exploring other agents. We propose that quantitating therapy-associated protein biomarkers including markers of antibody-drug conjugates (ADC) can improve treatment personalization for PaC. Methods: FFPE tumor tissues from 185 clinical PaC patients were microdissected and solubilized for mass spectrometry-based targeted proteomic analysis. We quantified biomarkers for ADCs simultaneously from 2-3 section of FFPE. These biomarkers include antibody targets such as EGFR, HER2, HER3, FRalpha, and Trop2 and payload biomarkers of sensitivity (TOPO1) and resistance (TUBB3). The multiplexed assay also quantified additional 65 clinically relevant protein biomarkers for chemotherapy, immunotherapy and targeted therapy. Results: Expression of EGFR was observed in majority of samples (88%) while only overexpressed ( > 1000 amol/µg) in 3% of samples. HER2 was expressed in half of patients (52%) and overexpressed ( > 750 amol/µg) in 5% of cases while the rest of HER2 protein expression ranged from 300 -750 amol/µg which corresponds to low Her2 expression. Trop2 was expressed in majority of patients (91%) with a 25x distribution between lowest and highest expressor. Other ADC biomarkers include HER3(55%, 5x), Axl (24%, 12x), Mesothelin (65%, 58x), Folate receptor alpha (10%, 17x). Expression of TUBB3 (77%, 8x) and TOPO1 (92%, 8x) in antibody target-positive subset may suggest resistance or response for several known payloads, such as taxanes and irinotecan/deruxtecan/govitecan, respectively. Conclusions: There is currently no approved ADC for pancreatic cancer, but several ADC clinical trials are underway. Quantitative proteomics identified antibody targets as well as markers of resistance or response to payloads for a variety of approved and investigational ADC therapies, which could aid in patient stratification in ADC clinical trials.

Odd- and even-numbered medium-chained fatty acids protect against glutathione depletion in very long-chain acyl-CoA dehydrogenase deficiency

Recent trials have reported the ability of triheptanoin to improve clinical outcomes for the severe symptoms associated with long-chain fatty acid oxidation disorders, including very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency. However, the milder myopathic symptoms are still challenging to treat satisfactorily. Myopathic pathogenesis is multifactorial, but oxidative stress is an important component. We have previously shown that metabolic stress increases the oxidative burden in VLCAD-deficient cell lines and can deplete the antioxidant glutathione (GSH). We investigated whether medium-chain fatty acids provide protection against GSH depletion during metabolic stress in VLCAD-deficient fibroblasts. To investigate the effect of differences in anaplerotic capacity, we included both even-(octanoate) and odd-numbered (heptanoate) medium-chain fatty acids. Overall, we show that modulation of the concentration of medium-chain fatty acids in culture media affects levels of GSH retained during metabolic stress in VLCAD-deficient cell lines but not in controls. Lowered glutamine concentration in the culture media during metabolic stress led to GSH depletion and decreased viability in VLCAD deficient cells, which could be rescued by both heptanoate and octanoate in a dose-dependent manner. Unlike GSH levels, the levels of total thiols increased after metabolic stress exposure, the size of this increase was not affected by differences in cell culture medium concentrations of glutamine, heptanoate or octanoate. Addition of a PPAR agonist further exacerbated stress-related GSH-depletion and viability loss, requiring higher concentrations of fatty acids to restore GSH levels and cell viability. Both odd- and even-numbered medium-chain fatty acids efficiently protect VLCADdeficient cells against metabolic stress-induced antioxidant depletion.

Association of Plasma Eicosanoid Levels With Immune, Viral, and Cognitive Outcomes in People With HIV

BACKGROUND AND OBJECTIVES

To determine whether plasma eicosanoid levels are associated with immune, viral, and cognitive outcomes in people with HIV (PWH).

METHODS

We measured 42 eicosanoids in a longitudinal study of 95 PWH and 25 demographically comparable uninfected participants. Routine clinical chemistry, virologic, immune markers, and a neuropsychological test battery assessing 7 cognitive domains were administered to all participants at 2 study visits over an average of 6.5 months.

RESULTS

Plasma eicosanoid concentrations were elevated in PWH (n = 95) compared with seronegative controls (n = 25) (100% prediction power at 5% false discovery rate [FDR], α = 0.0531) and were negatively associated with lower current and nadir CD4 lymphocyte counts. Higher levels of eicosanoids were associated with impairments in working memory, verbal fluency, and executive function. Higher plasma viral load was associated with elevated proinflammatory eicosanoids (24% prediction power at 5% FDR and 42.4% prediction power at 10% FDR, α = 0.10). Longitudinal analyses showed that eicosanoid levels were correlated with viral load and with plasma creatinine. Despite associations of eicosanoids with viral loads, elevated plasma eicosanoids were similar in virally suppressed and not fully suppressed PWH.

DISCUSSION

These data show that HIV infection is associated with a robust production of eicosanoids that are not substantially reduced by antiretroviral therapy (ART). The sustained elevation of these oxylipins in PWH despite ART may contribute to an accelerated aging phenotype that includes earlier than expected brain and peripheral organ damage.

Abstract 4099: Clinical survey of Trop2 antibody drug conjugate target and payload biomarkers in multiple cancer indications using multiplex mass spectrometry

Introduction: Trop2 is overexpressed in many cancers and currently Trop2 ADC is approved in TNBC. In ADC drug design, it is imperative to assess not only the levels of the receptor but also the payload biomarkers. We have developed a multiplex mass spectrometry method to quantitate 72 actionable proteins from FFPE samples that requires minimal tissue (2-3 sections). This panel includes chemotherapy, targeted therapy and immunotherapy agents. The test is run in our CAP, CLIA, and NYSDOH approved laboratory. For this study, we examined a subset of samples run in the clinical lab for the levels of Trop2 (target biomarker) and payload biomarkers (Topo1, TUBB3). Topo1 is a chemosensitive marker for irinotecan, while TUBB3 is a chemoresistance marker for tubulin inhibitors.

Methods: FFPE tissue sections from 1140 clinical samples from a variety of cancers were examined. These include breast (n=318), colorectal (n=228), ovarian (n=199), GBM (n=69), NSCLC (n=169), HNSCC (n=91), and Gastric cancer (n=66). Two sections (10 µ) of FFPE tissue were cut on DIRECTOR slides and only the tumor areas were laser microdissected for downstream analysis which resulted in tryptic peptides. 1µg of peptides (~4000 cells) along with heavy peptides was injected into a triple quad mass spec and 72 biomarkers were quantitated concurrently.

Results: Trop2 showed a wide range of expression in various cancers. Almost all (95%)breast cancer samples expressed Trop2 which exhibited a wide range (93x; 157 - 14650 amol/µg). Topo1 and TUBB3 were expressed in 93% and 60% of samples respectively. 1/4th of NSCLC does not express Trop2 and there is a 106x difference in expression of Trop2 in NSCLC. Topo1 was expressed in almost all samples while TUBB3 was expressed in 80% of NSCLC. Majority of ovarian cancer samples (85%), HNSCC (89%), Gastric cancer (88%) samples expressed Trop2 with a 113x, 134x, 47x difference in expression. Chemosensitive biomarker Topo1 was expressed in almost all ovarian (96%), HNSCC (91%) and Gastric (99%) cancer samples. Chemoresistant marker TUBB3 was expressed in 66% of ovarian cancer, 44% of HNSCC and 45% of gastric cancer samples. In contrast to above cancers, only 10% of Glioblastoma samples express Trop2 and only 3/4th of GBMs express Topo1.

Discussion: In a randomly selected group of cancers, we have found Trop2 is expressed in majority of Breast, Ovarian, Lung, HNSCC and gastric cancers and minimal expression in GBM. Given the range of expression of anti-tubulin resistance marker in many solid tumors, a payload biomarker guided clinical trial is highly recommended in ADCs that employ anti-tubulin inhibitors. In contrast, wide expression of chemosensitive biomarker for Topo1 payload makes it a promising candidate for many solid tumors. Further studies are warranted to determine the level of target and payload biomarkers that will be required for a clinical response.

Citation Format: Sheeno P. Thyparambil, Wei-Li Liao, Robert Heaton, Guolin Zhang, Amanda Strasbaugh, Marya Melkie, Xuefeng B. Ling. Clinical survey of Trop2 antibody drug conjugate target and payload biomarkers in multiple cancer indications using multiplex mass spectrometry [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4099.

AB1562-HPR COMPARING THE PROVISION OF SUBCUTANEOUS METHOTREXATE BETWEEN HOMECARE AND OUTPATIENT PHARMACY; WHAT DO PATIENTS PREFER AND IS ONE ROUTE QUICKER?

Background

The provision of subcutaneous methotrexate has historically been through homecare who provide injection training and delivery. In July 2018, subcutaneous methotrexate was accepted for shared care in the Trust’s locality to reduce medication costs but to also improve safety, reducing the risk of concomitant trimethoprim prescribing.

When suitable for shared care, initial injection training is provided by outpatient pharmacists and prescribing and monitoring during the stabilisation period is the responsibility of the rheumatology pharmacy team.

Objectives

The primary aim of this audit was to compare patient satisfaction between these two different routes of injection training and prescription provision. Additionally, the time it took for a patient to receive their first dose following a decision to start treatment, was also compared.

Methods

Patients were identified from databases held within the department, contacted retrospectively via telephone and asked to complete a short questionnaire. Clinic letters and the homecare company provided dates of treatment decision and initiation.

Results

40 patients were contacted, 20 had received treatment via outpatient pharmacy and 20 via homecare.

Table 1.

Patient reported satisfaction following receipt of injection training and prescription provision via outpatient pharmacy and homecare

Outpatient Pharmacy (20)Homecare (20)Not satisfiedSatisfiedVery satisfiedNot satisfiedSatisfiedVery satisfiedTime taken to start treatment25132612Injection training04163512Method for delivery of injection training and initial prescription18113413Process of receiving repeat prescriptions14151316

The mean time taken to start treatment was 30 days in the homecare group and 13 days in the outpatient group. 7 patients (35%) within the outpatient group started treatment within 7 days. The shortest time within the homecare group was 15 days (3 patients).

Conclusion

Reported patient satisfaction between the two routes of treatment provision was similar. Patients commenced treatment significantly quicker via outpatient pharmacy, reporting a high degree of satisfaction with the injection training provided by outpatient pharmacists. This audit has confirmed that shared care provision of methotrexate initially via outpatient pharmacy is a safe, efficient and viable option.

Disclosure of Interests

Rebecca Heaton Speakers bureau: I prepared slides and presented virtually for pharmacists explaining shared care experience (Nordic), Consultant of: Formulating a educational package for rheumatology pharmacists (Galapagos), Jennifer Nasralla: None declared, Charlotte Filer: None declared, Edward Appleby: None declared, Mya Myintzu: None declared

Development and validation of blood-based predictive biomarkers for response to PD-(L)-1 checkpoint inhibitors: Evidence of a universal systemic core of 3D immunogenetic profiling across multiple oncological indications

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Background: Unprecedented advantages in cancer treatments with immune checkpoint inhibitors (ICI) remain limited to a subset of patients, with high demands for development of better biomarkers to access likely clinical response in advance of ICI therapeutic interventions. 3D genomics has emerged as a novel molecular biomarker modality with strong functional correlation to clinical outcomes (1). The last few years have seen rapid emergence of 3D genomics applications in clinical stratifications. They have demonstrated high sensitivity and specificity in patient stratifications, offered solutions in symptomatic and pre-symptomatic diagnosis, in prognosis, residual disease monitoring, and prediction of response to therapeutic interventions (2-8). EpiSwitch is a 3D genomic platform that has been reduced to practice for the discovery of 3D genomic blood-based biomarkers in a variety of immune-related and oncological diseases (7,8). Methods: A clinical blood assay based on 8 markers - Checkpoint Inhibitor Response Test (CiRT) - has been developed to predict response to PD-(L)1 immune checkpoint inhibition from over 30 million data points, with validations on several independent cancer patient cohorts. The predictive 8 biomarker set is based on an observational clinical trial and several retrospective cohorts, representing all together 229 treatments with Pembrolizumab, Atezolizumab, Durvalumab, in over 15 diverse oncological indications, i.e. melanoma, lung, urethral, hepatocellular, bladder, prostate, head and neck, colon, breast, bone, brain, lymphoma, larynx. Results: CiRT has demonstrated high accuracy up to 85%, sensitivity of 93% and specificity of 82%. Conclusions: This study demonstrates that a 3D genomic approach could be successfully utilized for development of a non-invasive predictive clinical assay for response to PD-(L)1 checkpoint inhibition in cancer patients. CiRT can assist in treatment decisions, help improve patient selection for optimized treatment, utilize alternative effective treatments, minimize unnecessary toxicity, and efficiently manage the costs.

Deviation from the precisely timed age-associated patterns revealed by blood metabolomics to find CRC patients at risk of relapse at the CRC diagnosis

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Background: Human serum metabolome profiles have been analyzed to explore the molecular changes that occur with aging. We hypothesized that deep metabolic profiling of sera with different ages would allow the identification of distinct metabolic chronologic patterns as a normal biological baseline to study personal aging. We further hypothesized that metabolic assessment of this chronologic deviation, resulting from advanced precancerous lesion (APL) and stage I/II/III CRC, from the normal reference baseline, would be instrumental for prognosis of relapse revealing underlying pathophysiology. Methods: A cohort of normal (n=3,616, training; n=1,170, testing), 631 advanced adenoma, 1,019 stage I, 404 stage II and 417 stage III serum samples were assembled. Innovative global LCMS metabolomic production were applied to deep profile these subjects. Identification of the age-associated molecular patterns in normal subjects, modeled with an elastic net algorithm, established the reference baseline to mirror a metabolic clock. CRC associated deviation from the precise chronologically paced metabolic patterns was quantified to associate the clinical endpoints of relapse, OSF and PFS, and to identify the tightly associated metabolic pathways. Results: We observed that for those CRCs, the predicted metabolic age can differ from the chronological age with consistent variations, resulting “older” or “younger” metabolic age subgroup in reference to the chronological age. Significant disruptions from the normal baseline were observed in CRCs patients, and consistent stage specific patterns were observed. Outlier, “Older” or “younger” metabolic age subgroup, CRC patients were found with significant future relapse enrichment. Predictive models were derived to case find the patients at risk of future relapse at the CRC diagnosis timepoint. Conclusions: Deviations from the meticulously timed metabolic aging patterns may provide utility to allow prognosis of future clinical endpoints of relapse and overall survival. Close examination of the underlying metabolic pathways, associated with CRC stage specific metabolic patterns, disrupting the baseline ageotypes, not only may improve the sensitivity and specificity of prognostic tests of CRC relapse, but also shed new insights into CRC therapeutics.

Quantitative proteomic profiling of esophageal adenocarcinoma tumors to assess prevalence of approved targets and elucidate novel biomarkers

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Background: Esophageal adenocarcinoma (EAC) continues to have extremely poor prognosis despite advances in surgical and oncological regimens. Targeted and immune therapy hold promise to improve outcomes in solid tumors including EAC. At present HER-2 and anti-PD-L1 therapies are approved by the FDA for EAC. Additionally, off-label use of EGFR directed therapy has been reported. The aim of this study is to measure expression of 80+ oncoproteins in EAC using multiplexed mass spectrometry to elucidate expression of currently approved-drug targets and explore promising new targets for drug development. Methods: After Institutional Review Board approval (Mayo Clinic and KUMC), EAC patients whose tumors were resected via esophagectomy before chemotherapy and/or radiation were identified. Normal esophageal mucosa samples with no history of EAC were also retrieved for analysis. Tissue sections were microdissected to exclude stroma from adenocarcinoma cells. Isolated EAC cells were solubilized for mass spectrometry-based quantitation of more than 80 clinically relevant tumor markers. Results: 55 EAC tissues were analyzed. HER2, PD-L1 and EGFR were overexpressed only in 16.3%, 0%, and 0% of patients, respectively. New oncoproteins #2 and #6 were noted to have high (7,634.0 and 27,222.6 attomoles/ug) and consistent (98.1% and 94.5%) overexpression in EAC samples. Expression of HER2, oncoproteins #2 and #6 were significantly higher in EAC compared to normal esophageal mucosa. There was no statistical difference in the expression of PD-L1 and EGFR between EAC and normal samples. Conclusions: Mass spectrometry revealed a very low prevalence of target oncoproteins in EAC for currently used drugs. Our study potentially reveals alternate markers which are near universally present at high levels and should be further explored for targeted treatment.[Table: see text]

Importance of Cobalt-60 Dose Rate and Biologically Effective Dose on Local Control for Intracranial Meningiomas Treated With Stereotactic Radiosurgery

BACKGROUND

Radiosurgery dose rate and biologically effective dose (BED) are associated with outcomes after stereotactic radiosurgery (SRS) for functional neurosurgical conditions and some benign tumors. It is not known if these factors affect the efficacy of SRS for meningioma.

OBJECTIVE

To determine the association between cobalt-60 dose rate and BED on outcomes in patients with meningioma treated with SRS.

METHODS

A single-institution cohort of 336 patients treated between 2005 and 2018 with cobalt-based SRS for 414 separate meningioma lesions was assembled. BED was calculated using an SRS-specific monoexponential model accounting for treatment time per lesion, assuming α/β = 2.47 Gy. Cumulative incidences of local failure (LF) were reported after considering the competing risk of death, on a per-lesion basis. Multivariable analysis of LF was performed using a proportional hazards model.

RESULTS

The most common SRS dose was 12 Gy (n = 227); 140 lesions received 14 Gy. Five-year LF was 15.6% (95% confidence interval 10.4-21.9) and 4.3% (1.4-9.8) in patients who had a dose rate of <2.95 and ≥2.95 Gy/min, respectively (P = .0375). Among 354 grade I or unresected lesions treated with SRS, BED >50 Gy2.47 was associated with a lower incidence of LF (P = .0030). Each 1 Gy/min increase in dose rate was associated with an adjusted hazard ratio of 0.53 (95% confidence interval, 0.29-0.97, P = .041) for LF. Prescription dose >12 Gy was not associated with a lower incidence of LF.

CONCLUSION

Patients with meningiomas treated with lower dose rates experienced a higher incidence of LF than those treated with higher dose rates.

Associations Between HIV Stigma and Mental Health Among Older Hispanics and Whites Living With HIV

Older immigrants totaled 7.3 million in 2018, representing 13.9 percent of the population of seniors in the U.S. While this population is found to contribute significantly to society, along with new opportunities comes circumstantial challenges. Of these, one of the most salient issues for foreign-born older adults is social isolation. Additionally, this population may be at an increased risk for social isolation with poor mental health because migrating to a new country might results in resettlement challenges. Despite these concerns, less is known about the consequences of social isolation among older immigrant adults. Guided by the Population Interest Context (PICO) framework and the Qualitative Interpretive Meta-Synthesis (QIMS) guidelines, this study seeks to explore consequences of social isolation among older immigrant, as well as interventions to combat isolation. The final sample of six full text articles were published between 2011 and 2021, totaling 180 participants with ages ranging from 61 to 93 years old. Findings from the study indicated that older immigrants are at risk of social isolation and loneliness because they have fewer social connections due to leaving behind their familiar social group in the home country, encounter linguistic challenges that negatively contribute to greater social isolation and poor mental health. Despite these difficulties older immigrants reported various social interventions, i.e., access to senior centers, community programs and services to be of greater importance in building social networks. Authors discuss opportunities for future research, such as exploring evidence-based studies on interventions for social isolation and loneliness of older immigrant populations.

Metabolic Syndrome and Neurocognitive Function among older Hispanics/Latinos with HIV

Neurocognitive impairment is prevalent among persons with HIV (PWH), particularly among Hispanics/Latinos/as/x (henceforth Hispanics). We examined disparities in HIV-associated neurocognitive function between older Hispanic and non-Hispanic White PWH, and the potential role of metabolic syndrome (MetS) in explaining these disparities. Participants included 116 community-dwelling PWH ages 50-75, who were enrolled in a cohort study in southern California (58 Hispanic [53% Spanish-speaking] and 58 age-comparable non-Hispanic White; Overall group: Age: M=57.9, SD=5.7; Education: M=13, SD=3.4; 83% male, 58% AIDS, 94% on antiretroviral therapy [ART], 4% detectable plasma RNA). A global neurocognition score was derived from T-Scores on a comprehensive neurocognitive battery, with separate demographic adjustments for English and Spanish-speakers. MetS was ascertained via standard criteria that considered central obesity, elevated triglycerides, low high-density lipoprotein cholesterol, and elevated fasting glucose, as well as current medical treatment for these conditions. Covariates examined included sociodemographic, psychiatric, substance use and HIV-disease characteristics. Hispanics had higher rates of MetS (56%) than non-Hispanic Whites (37%; p<.05). A stepwise regression model on global neurocognition including ethnicity and covariates that differed between ethnic groups, selected only Hispanic ethnicity as a significant predictor (B=-3.82, SE=1.27, p<.01). A comparable model also including MetS showed that both Hispanic ethnicity (B=-3.39, SE=1.31, p=.01) and MetS (B=-2.73, SE=1.31, p=.04), were significantly associated with worse global neurocognition. Findings indicate that MetS does not fully explain disparities in neurocognitive function between Hispanic and non-Hispanic White older PWH, but rather is an independent predictor of neurocognitive function along with Hispanic ethnicity.

Paresthesia Predicts Increased Risk of Distal Neuropathic Pain in Older People with HIV-Associated Sensory Polyneuropathy

OBJECTIVE

Distal sensory polyneuropathy (DSP) is a disabling consequence of human immunodeficiency virus (HIV), leading to poor quality of life and more frequent falls in older age. Neuropathic pain and paresthesia are prevalent symptoms; however, there are currently no known curative treatments and the longitudinal course of pain in HIV-associated DSP is poorly characterized.

METHODS

This was a prospective longitudinal study of 265 people with HIV (PWH) enrolled in the CNS HIV Antiretroviral Therapy Effects Research (CHARTER) study with baseline and 12-year follow-up evaluations. Since pain and paresthesia are highly correlated, statistical decomposition was used to separate the two symptoms at baseline. Multivariable logistic regression analyses of decomposed variables were used to determine the effects of neuropathy symptoms at baseline on presence and worsening of distal neuropathic pain at 12-year follow-up, adjusted for covariates.

RESULTS

Mean age was 56 ± 8 years, and 21% were female at follow-up. Nearly the entire cohort (96%) was on antiretroviral therapy (ART), and 82% had suppressed (≤50 copies/mL) plasma viral loads at follow-up. Of those with pain at follow-up (n = 100), 23% had paresthesia at the initial visit. Decomposed paresthesia at baseline increased the risk of pain at follow-up (odds ratio [OR] 1.56; 95% confidence interval [CI] 1.18, 2.07), and decomposed pain at baseline predicted a higher frequency of pain at follow-up (OR 1.96 [95% CI 1.51, 2.58]).

CONCLUSIONS

Paresthesias are a clinically significant predictor of incident pain at follow-up among aging PWH with DSP. Development of new therapies to encourage neuroregeneration might take advantage of this finding to choose individuals likely to benefit from treatment preventing incident pain.

Radiation Dose Rate, Biologically Effective Dose, and Tumor Characteristics on Local Control and Toxicity After Radiosurgery for Acoustic Neuromas

OBJECTIVE

To evaluate the relationships between calibration dose rate, calculated biologically effective dose (BED), and clinical factors and tumor control after stereotactic radiosurgery (SRS) for acoustic neuroma.

METHODS

We performed a retrospective study of all patients with acoustic neuromas treated with frame-based cobalt-60 SRS at a single institution between 2005 and 2019. The calibration dose rate and cobalt-60 half-life were used to calculate the nominal dose rate during treatment. An SRS-specific monoexponential model accounting for treatment time per lesion was used to estimate BED.

RESULTS

The study included 607 patients with 612 acoustic neuromas. Median follow-up was 5.0 years. There was no association between dose rate or BED with local failure (LF), radiologic edema, or symptomatic edema. Cystic tumors (adjusted hazard ratio 0.26, P = 0.028) were associated with lower LF, while use of SRS as salvage treatment for growing tumors (adjusted hazard ratio 4.9, P < 0.0001) was associated with higher LF. LF occurred more frequently in larger-diameter tumors, while radiologic or symptomatic edema occurred more frequently in larger-volume tumors.

CONCLUSIONS

Radiosurgery dose rate and BED were not associated with tumor control or radiologic or symptomatic edema. Salvage SRS and larger tumors were associated with a higher LF rate, while cystic tumors were associated with a lower LF rate. Patients with larger tumors should be counseled appropriately about potential side effects and when to seek follow-up care.

Multi-omics longitudinal analyses in stages I to III CRC patients: Surveillance liquid biopsy test to predict early recurrence and enable risk-stratified postoperative CRC management

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Background: One-third of colorectal cancer (CRC) recurs following curative surgery and chemotherapy. Accordingly, novel methods are needed to predict recurrence to enable clinical course mitigating strategies. Serial monitoring of plasma by mass spectrometry (MS) and multi-omics modeling (MMO) of CRC relapse chronology provide the framework for liquid biopsy test development to supersede existing imaging modalities such as CT scans according to relapse related pathologies. We hypothesized that plasma MS and MMO analysis of relapse related pathologies can deconvolute high risk stratification for CRC recurrence within the cancer continuum of care pre/post-surgery and/or pre/post adjuvant chemotherapy (ACT). Methods: 189 CRC patients (Stage I-III) underwent one of three treatment modalities: Modality 1 (Surgery followed by ACT), Modality 2 (Surgery only), Modality 3 (Neoadjuvant chemotherapy followed by surgery and ACT). Plasma samples (n = 441) were collected from patients before surgery, 30 days post-op, and every 3 months until death or month 24 whichever came first. The MMO approach was used to analyze biological features encompassing native peptides, proteins, metabolites, lipids, and ceramides. MMO panels were developed comprising the significantly perturbed features as per the treatment modalities. These panels were used to predict relapse from plasma collected pre-op, 30-day post-op or after adjuvant chemotherapy. CEA levels were monitored in parallel. Results: Follow-up data was available for 135 patients (Stage I-III) and 25/135 had evidence of radiological recurrence. Irrespective of the treatment modality, longitudinal follow-up using the MMO panel was able to predict disease recurrence greater than 7 months before clinical progression was confirmed by CT scan. There was no significant correlation between longitudinal CEA levels and recurrence status, hence CEA levels alone did not provide any lead time advantage over the MMO panel or radiological surveillance. Kaplan-Meier (KM) survival analysis revealed that patients that were MMO panel positive had a poor survival irrespective of treatment modalities used: Modality 1 (HR = 6.2, p value = 0.003, test immediately post-surgery and immediately before ACT; HR = 31.6, p value = 0.01, test immediately after ACT); Modality 2 (HR = 11.2; p value = 0.01, test immediately after-surgery); Modality 3 (HR > 40, p value = 0.08, test immediately after neo-ACT and before-surgery; HR > 40, p value = 0.004, test immediately after-surgery). Conclusions: The MMO panel predicts CRC recurrence several months prior to detection by conventional CT scans, thus providing opportunity for alternative therapeutic strategies much earlier in the disease course.

Telomere length is associated with HIV infection, methamphetamine use, inflammation, and comorbid disease risk

BACKGROUND

HIV infection and methamphetamine dependence (METH) are each associated with inflammation and premature aging, but their impact on biological aging is difficult to measure. Here we examined the impact of HIV and METH on leukocyte telomere lengths (LTL), and the correlations between LTL and other aging biomarkers.

METHODS

The study was a cross-sectional analysis of 161 individuals categorized by HIV and methamphetamine (METH) dependence status into four groups: HIV-METH- (n = 50), HIV-METH+ (n = 29), HIV + METH- (n = 40), and HIV + METH+ (n = 42). We analyzed the relationships of leukocyte telomere length (telomere to single copy gene [T/S] ratio) with demographic and clinical data as well as a panel of biomarkers of inflammation and endothelial activation measured in blood and cerebrospinal fluid (CSF).

RESULTS

HIV and METH were independently associated with shorter T/S ratio, even after adjusting for demographics and leukocyte count (R2 = 0·59, p < 0·0001). Higher plasma C-reactive protein (p = 0·0036) and CSF VCAM-1 (p = 0·0080) were also associated with shorter T/S ratio. A shorter T/S ratio was associated with higher risk for cardiovascular disease (p < 0·0001) and stroke (p < 0·0001), worse motor functioning (p = 0·037) and processing speed (p = 0·023), more depressive symptoms (p = 0·013), and higher CSF neurofilament-light (p = 0·003).

CONCLUSIONS

HIV and METH dependence were each associated with shorter telomeres. After adjusting for demographics, HIV, and METH, T/S ratio remained associated with aging-related outcomes including neurocognitive impairment, neurodegeneration, risks of cardiovascular disease and stroke. While not establishing causality, this study supports using the T/S ratio as a biomarker for estimating the impact of HIV and comorbidities on long-term health.

Bezafibrate activation of PPAR drives disturbances in mitochondrial redox bioenergetics and decreases the viability of cells from patients with VLCAD deficiency

Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is the most common inborn long-chain fatty acid oxidation (FAO) disorder. VLCAD deficiency is characterized by distinct phenotypes. The severe phenotypes are potentially life-threatening and affect the heart or liver, with a comparatively milder phenotype characterized by myopathic symptoms. There is an unmet clinical need for effective treatment options for the myopathic phenotype. The molecular mechanisms driving the gradual decrease in mitochondrial function and associated alterations of muscle fibers are unclear. The peroxisome proliferator-activated receptor (PPAR) pan-agonist bezafibrate is a potent modulator of FAO and multiple other mitochondrial functions and has been proposed as a potential medication for myopathic cases of long-chain FAO disorders. In vitro experiments have demonstrated the ability of bezafibrate to increase VLCAD expression and activity. However, the outcome of small-scale clinical trials has been controversial. We found VLCAD deficient patient fibroblasts to have an increased oxidative stress burden and deranged mitochondrial bioenergetic capacity, compared to controls. Applying heat stress under fasting conditions to bezafibrate pretreated patient cells, caused a marked further increase of mitochondrial superoxide levels. Patient cells failed to maintain levels of the essential thiol peptide antioxidant glutathione and experienced a decrease in cellular viability. Our findings indicate that chronic PPAR activation is a plausible initiator of long-term pathogenesis in VLCAD deficiency. Our findings further implicate disruption of redox homeostasis as a key pathogenic mechanism in VLCAD deficiency and support the notion that a deranged thiol metabolism might be an important pathogenic factor in VLCAD deficiency.

Native Spanish-speaker's test performance and the effects of Spanish-English bilingualism: results from the neuropsychological norms for the U.S.-Mexico Border Region in Spanish (NP-NUMBRS) project

Objective: We aimed to investigate whether or not demographically-corrected test scores derived from the Neuropsychological Norms for the U.S.-Mexico Border Region in Spanish (NP-NUMBRS) would be less accurate if applied to Spanish-speakers with various degrees of English fluency. Spanish-English Method: One hundred and seventy primarily Spanish-speaking adults from the NP-NUMBRS project completed a comprehensive neuropsychological test battery. T-scores adjusted for age, education, and sex (but not degree of bilingualism), were derived for each test utilizing population-specific normative data. English fluency was assessed via the Controlled Oral Word Association Test in English (F-A-S), and Spanish fluency with "P-M-R," and degree of relative English fluency was calculated as the ratio of English language words over total words produced in both languages. Effects of degree of bilingualism on the NUMBRS battery test scores (raw scores and T-scores) were examined via Pearson's product moment correlation coefficients, and language groups (Spanish dominant vs. relative bilingual) were compared on demographically adjusted T-scores via independent samples t-tests. Results: Higher Spanish-English bilingualism was associated with higher education and SES, and was significantly associated with higher raw scores on all tests, but only associated with higher T-scores on a limited number of tests (i.e., WAIS-III Digit Symbol, Symbol Search, Letter-Number Sequencing and Trails B). Conclusion: Degree of Spanish-English bilingualism generally did not account for significant variance in the normed tests beyond the standard demographic adjustments on most tests. Overall, the normative adjustments provided by the NP-NUMBRS project appear applicable to native Spanish speakers from the U.S.-Mexico border region with various degrees of Spanish-English bilingualism.

RADT-19. EFFECTS OF RADIATION DOSE-RATE AND TUMOR CHARACTERISTICS ON LOCAL CONTROL AND TOXICITY AFTER RADIOSURGERY FOR ACOUSTIC NEUROMAS

INTRODUCTION

The effect of stereotactic radiosurgery (SRS) dose-rate on tumor control for acoustic neuroma (AN, or vestibular schwannoma) is unclear.

METHODS

This was a retrospective study of all patients treated for AN with frame-based cobalt-60 SRS at the Toronto Western Hospital between 2005-2019. Dose rates on the day of SRS were calculated from the calibration dose-rate while accounting for the cobalt-60 half-life of 5.2713 years. Local failure was defined as continued tumor growth &gt;36 months post-SRS, tumor resection for LF, or use of any repeat SRS for LF. Cumulative incidence of LF was reported after accounting for competing risks of death, on a per-lesion basis. Comparisons of actuarial LF were made using Gray’s test. Multivariable analysis of LF was performed using a proportional hazards model.

RESULTS

A total of 607 patients were treated for 617 acoustic neuromas. Median follow-up was 5.0 years. 158 tumors (26%) were cystic. 71 tumors (12%) had previous resection. Nine patients received 10-11 Gy due to large tumor size; all remaining patients received 12 Gy to approximately the 50% isodose line. Median dose rate was 2.4 Gy/min (range, 1.3-3.7). There was no association between dose rate and LF (≥ 2.4 Gy/min vs. &lt; 2.4 Gy/min, 6.07% vs. 6.12% at 5-year follow-up, p = 0.75). The adjusted local failure-specific hazard ratio (HR) for dose rate (per Gy/min) was 1.2 (95% CI 0.69-2.1, p = 0.52). Patients with previous surgery had higher LF, with a HR of 3.6 (95% CI 1.7-7.8, p = 0.0012), after adjusting for presence of cysts (HR 0.27, p = 0.034) and maximum tumor diameter (HR 1.055 per cm, p = 0.071).

CONCLUSIONS

In a large cohort of patients with acoustic neuromas, radiosurgery dose-rate was not associated with tumor control. Previous resection was a strong risk factor for local failure after SRS.

Reduced Independence in Daily Living Is Associated with the Gut Microbiome in People with HIV and HCV

Alterations in the gut microbiome are associated with neurocognition and related disorders, including in the context of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infection. However, the connection between the gut microbiome and cognitive decline, gauged by increased dependence in instrumental activities of daily living (IADL), remains largely unexplored in the context of these diseases. Here we characterized the gut microbiome using 16S rRNA amplicon sequencing and untargeted metabolomics with liquid chromatography-mass spectrometry from 347 people with HIV, HIV and HCV, or neither, all of whom underwent a comprehensive neuropsychiatric assessment. We observed that IADL-dependent and -independent HIV-monoinfected (HIV-positive [HIV+]/HCV-negative [HCV-]) and coinfected (HIV+/HCV+) individuals have distinct gut microbiomes. Moreover, we found that dependent individuals with HIV or HIV and HCV were enriched in Bacteroides These results may have implications for the characterization of cognitive decline, as well as the development of potential prevention and treatment strategies for individuals infected with HIV and/or HCV. Of particular interest is the possibility that dietary interventions that are known to modify the microbiome could be used to shift the microbiome toward more favorable states for preserving independence.IMPORTANCE The microbes in the gut and the chemicals they produce by metabolism have been linked to brain function. In earlier work, we showed that infection with two viruses, HIV and HCV, changed the gut microbes and metabolism in ways that were associated with a lifetime history of major depressive disorder. Here, we extend this analysis looking at a measurement of independence in daily living. We find that in individuals with HIV, whether or not they also have HCV, those who reported reduced independence were enriched in a genus of bacteria called Bacteroides This result is interesting because Bacteroides is strongly associated with diets low in carbohydrates and high in animal protein, suggesting that diet changes may help preserve independent living in people living long-term with HIV (although clinical intervention trials would be needed in order to confirm this).

Depression in Individuals Coinfected with HIV and HCV Is Associated with Systematic Differences in the Gut Microbiome and Metabolome

Depression is influenced by the structure, diversity, and composition of the gut microbiome. Although depression has been described previously in human immunodeficiency virus (HIV) and hepatitis C virus (HCV) monoinfections, and to a lesser extent in HIV-HCV coinfection, research on the interplay between depression and the gut microbiome in these disease states is limited. Here, we characterized the gut microbiome using 16S rRNA amplicon sequencing of fecal samples from 373 participants who underwent a comprehensive neuropsychiatric assessment and the gut metabolome on a subset of these participants using untargeted metabolomics with liquid chromatography-mass spectrometry. We observed that the gut microbiome and metabolome were distinct between HIV-positive and -negative individuals. HCV infection had a large association with the microbiome that was not confounded by drug use. Therefore, we classified the participants by HIV and HCV infection status (HIV-monoinfected, HIV-HCV coinfected, or uninfected). The three groups significantly differed in their gut microbiome (unweighted UniFrac distances) and metabolome (Bray-Curtis distances). Coinfected individuals also had lower alpha diversity. Within each of the three groups, we evaluated lifetime major depressive disorder (MDD) and current Beck Depression Inventory-II. We found that the gut microbiome differed between depression states only in coinfected individuals. Coinfected individuals with a lifetime history of MDD were enriched in primary and secondary bile acids, as well as taxa previously identified in people with MDD. Collectively, we observe persistent signatures associated with depression only in coinfected individuals, suggesting that HCV itself, or interactions between HCV and HIV, may drive HIV-related neuropsychiatric differences.IMPORTANCE The human gut microbiome influences depression. Differences between the microbiomes of HIV-infected and uninfected individuals have been described, but it is not known whether these are due to HIV itself, or to common HIV comorbidities such as HCV coinfection. Limited research has explored the influence of the microbiome on depression within these groups. Here, we characterized the microbial community and metabolome in the stools from 373 people, noting the presence of current or lifetime depression as well as their HIV and HCV infection status. Our findings provide additional evidence that individuals with HIV have different microbiomes which are further altered by HCV coinfection. In individuals coinfected with both HIV and HCV, we identified microbes and molecules that were associated with depression. These results suggest that the interplay of HIV and HCV and the gut microbiome may contribute to the HIV-associated neuropsychiatric problems.

Abstract 4156: Molecular profiling of ovarian cancer by targeted proteomics to inform personalized therapy

Chemotherapy is the mainstay for the treatment of ovarian cancer. Taxanes, platinum salts, 5-FU, anthracyclines, gemcitabine are used extensively in ovarian cancer, however, there is no biomarker of chemotherapy that is routinely used. We examined 169 ovarian cancer samples using targeted proteomics for biomarkers of response or resistance to chemotherapy agents. Biomarkers of resistance include ERCC1 (Platinum), TUBB3 (taxanes), ALDH1A1 (cyclophosphamide) while response biomarkers include TOPO1 (irinotecan, topotecan), TOPO2A (doxorubicin, epirubicin), hENT1 (Gemcitabine).We also measure markers for several antibody-drug conjugates (FR-alpha, Her2, Trop2, gPNMB, MSLN).

Methods: Tumor areas from Formalin-fixed, paraffin-embedded (FFPE) tumor tissues from clinical samples of ovarian cancer that were received at our CLIA certified laboratory were microdissected and a selected reaction monitoring mass spectrometry (SRM-MS) quantitative proteomic analysis of 72 biomarkers were conducted.

Discussion: The majority of ovarian cancer samples expressed a range of resistance markers for cyclophosphamide (ALDH1A1: 87% positive ranging from 227-10766 amol/µg), platinum agents (70% positive) and taxanes (71%positive). However, they also expressed a range of response biomarkers for chemotherapies that are conventionally used to treat ovarian cancer. These include irinotecan/topotecan (TOPO1: 97% positive ranging from 459 -3299), doxorubicin (TOPO2A: 50% positive ranging from 402-3825 amol/µg), gemcitabine (hENT1/RRM1: 42% positive). Novel chemotherapy agents that could potentially be used include temozolomide (40% of patients did not express MGMT, resistance marker for temozolomide). The vast majority (78%) of ovarian cancer samples did not express any drug efflux pump proteins MRP and MDR1. Examination of potential ADC markers revealed 74% positivity for the antibody target FR-alpha with a 42 fold range of expression (585 -25000 amol/µg) and 71% positivity for the payload resistance marker TUBB3. Similarly, Trop2 (56% positivity) exhibited a wide dynamic range (222-12778 amol/µg). Another ADC target mesothelin was expressed in 66% of the cases with a 35x range of expression (302 - 10,700 amol/µg). While 56% of ovarian cancer expressed Her2 (262 -5011 amol/µg), only 4% expressed high levels of Her2 (&gt;750 amol/µg), making them suitable for current anti-Her2 therapy. Others could potentially benefit from clinical trials targeting low Her2 expression. The ability to multiplex 72 protein biomarkers from 2-3 FFPE sections provides immense actionable information on clinical treatment or for patient stratification for clinical trials.

Citation Format: Sheeno P. Thyparambil, Wei-Li Liao, Eunkyung An, Anuja Bhalkikar, Thomas Guiel, Robert Heaton. Molecular profiling of ovarian cancer by targeted proteomics to inform personalized therapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4156.

Impact of Latent Tuberculosis Infection on Neurocognitive Functioning and Inflammation in HIV-Infected and Uninfected South Indians

BACKGROUND

HIV-associated neurocognitive disorder persists in some people living with HIV despite optimal antiretroviral therapy. Latent tuberculosis infection (LTBI) may cause systemic inflammation and immune activation that may impair brain function. We assessed cognition and biomarkers of inflammation in both HIV+ and HIV- South Indians with and without LTBI.

METHODS

Adults (≥18 years old) with and without HIV infection were screened for LTBI by interferon-gamma release assays, completed comprehensive neurocognitive assessments, and underwent measurement of serum inflammatory biomarker levels.

RESULTS

The participants (n = 119) were HIV+/LTBI+ (n = 15), HIV+/LTBI- (n = 50), HIV-/LTBI+ (n = 26), and HIV-/LTBI- (n = 28). HIV+ participants, regardless of LTBI status, had more impaired global deficit scores than HIV- participants (odds ratio = 3.42, P = 0.028, adjusted for sex and education differences). Neither global deficit scores nor impairment rates differed in the LTBI+ group compared with the LTBI- group (P = 0.79 and P = 0.41, respectively). The mean log10 interleukin (IL)-6 and monocyte chemoattractant protein-1 values were significantly higher and high sensitivity C-reactive protein lower in the LTBI+ group than the LTBI- group (P = 0.044, 0.023, and 0.03, respectively, adjusting for HIV status and sex).

CONCLUSIONS

In this cross-sectional study of South Indians, HIV infection, but not LTBI, was associated with increased neurocognitive impairment. Proinflammatory biomarkers (IL-6 and monocyte chemoattractant protein-1, but not tumor necrosis factor-α) were elevated in the LTBI+ groups compared with the LTBI- groups. Biomarkers of immune activation (interferon-γ, macrophage inflammatory protein-1β, IL-2, interferon gamma inducible protein-10, RANTES, and IL-22) did not differ between these groups. Larger longitudinal studies should be conducted to confirm our findings that the effect of LTBI on systemic inflammation or neurocognitive impairment is likely small.

Moment-to-Moment Associations Between Depressive Symptoms and Daily Functioning Among Stroke Survivors: An Ecological Momentary Assessment (EMA) Study

Date Presented 03/27/20

This study used smartphone-based EMA to investigate moment-to-moment associations between poststroke depressive symptoms and daily functioning. We found that fatigue and lack of interest can be target symptoms to improve daily functioning among stroke survivors. Improving self-appraisals of daily functioning can be an effective way to manage depressive symptoms. EMA can be a useful tool to track real-time target symptoms in naturalistic contexts.

Primary Author and Speaker: Yejin Lee

Additional Authors and Speakers: Eric Lenze, Carolyn Baum, Jin-Moo Lee, Christopher Metts, Michael Yingling, Robert Fucetola, Mandy Fong, Colin Depp, Robert Heaton, Chenyang Lu, Albert Lai

Contributing Authors: Alex Wong

Emotional health outcomes are influenced by sexual minority identity and HIV serostatus

For people living with HIV (PLWH) and sexual minorities (SM), the intersection of identities can compound experiences like stigma and discrimination resulting in poor emotional health. We investigated the separate and interactive associations of HIV serostatus and sexual identity with emotional health. Our dataset included 371 participants. Emotional health was assessed by the NIH Toolbox emotion battery which yields negative affect, social satisfaction, and psychological well-being. Regressions were conducted for each composite, with HIV serostatus, sexual identity, and their interaction as independent variables along with covariates. The HIV serostatus x SM identity interaction was statistically significant in the regression of Negative Affect (p = .01): heterosexuals living with HIV had worse Negative Affect compared to heterosexual HIV-persons (p = .01). The interaction terms were for social satisfaction and psychological well-being were not significant. However, among PLWH, sexual minorities reported better Social Satisfaction (p = .03) and marginally better psychological well-being (p = .07) compared to heterosexuals.

Proteomic profiling to identify therapeutics targets in glioblastoma (GBM)

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Background: Glioblastoma (GBM) is an aggressive primary brain tumor with poor prognosis. Treatment at diagnosis is largely confined to surgery, radiation and temozolomide (TMZ) with median progression-free survival (PFS) of 7 months and median overall survival (mOS) of 15 months. GBM tumors recur in most cases and in patients with recurrent GBM, the mOS is 6.2 months. The lack of effective therapies underscores the importance of exploring other agents. We propose that quantitating therapy-associated protein biomarkers can improve treatment personalization for GBM. Methods: 97 FFPE GBM tissues were microdissected and solubilized for mass spectrometry-based proteomic analysis of therapy-associated protein biomarkers in our CLIA certified lab. We quantified protein levels of MGMT, hENT1, RRM1, TOPO1 and EGFR/TUBB3 (antibody target and payload resistance markers, respectively, for anti-EGFR ADCs) simultaneously. The multiplexed assay also quantified additional 24 clinically relevant proteins. Results: 43/57 patients were predicted to respond to TMZ based on undetectable levels of MGMT, confirming wide utility of this agent. 42/97(43%) patients were predicted to have gemcitabine sensitivity based on high expression of the response marker (hENT1 > 100 amol/ug) and low expression of the resistance marker (RRM1 < 700 amol/ug). 11/97(11%) patients expressed TOPO1 > 1350 amol/ug (75th percentile of all indications tested by author’s laboratory), suggesting likely response to irinotecan and topotecan. EGFR expression ranged from < 100 amol/ug to > 25000 amol/ug, including overexpression (> 1500 amol/ug) in 22%(21/97) of cases. While expression of EGFR(81/97, 84%) suggested likely response to anti-EGFR ADC, concurrent expression of TUBB3(78/81) may indicate resistance to several known payloads, such as taxanes and MMAE. Conjugation with another payload that targets sensitivity marker TOPO1 (68% expression) is a likely option. Proteomic analysis also revealed detectable levels of multiple RTKs (FGFR(4), AXL(20), IGF1R(10), MET overexpression(1), and HER2 overexpression(2)), indicating potential response to RTK inhibitors. Exploratory investigation in tumor vs TME using proteomics and metabolomics is ongoing. Conclusions: In this population of GBM patients, proteomic analysis identified protein targets of multiple approved and investigational therapies. Gemcitabine, which crosses the blood-brain barrier, may be considered as a salvage option after TMZ failure. Proteomic quantitation of EGFR and TUBB3 may improve patient selection for EGFR-targeting ADCs.

Expression of mutant exon 1 huntingtin fragments in human neural stem cells and neurons causes inclusion formation and mitochondrial dysfunction

Robust cellular models are key in determining pathological mechanisms that lead to neurotoxicity in Huntington's disease (HD) and for high throughput pre‐clinical screening of potential therapeutic compounds. Such models exist but mostly comprise non‐human or non‐neuronal cells that may not recapitulate the correct biochemical milieu involved in pathology. We have developed a new human neuronal cell model of HD, using neural stem cells (ReNcell VM NSCs) stably transduced to express exon 1 huntingtin (HTT) fragments with variable length polyglutamine (polyQ) tracts. Using a system with matched expression levels of exon 1 HTT fragments, we investigated the effect of increasing polyQ repeat length on HTT inclusion formation, location, neuronal survival, and mitochondrial function with a view to creating an in vitro screening platform for therapeutic screening. We found that expression of exon 1 HTT fragments with longer polyQ tracts led to the formation of intra‐nuclear inclusions in a polyQ length‐dependent manner during neurogenesis. There was no overt effect on neuronal viability, but defects of mitochondrial function were found in the pathogenic lines. Thus, we have a human neuronal cell model of HD that may recapitulate some of the earliest stages of HD pathogenesis, namely inclusion formation and mitochondrial dysfunction.

Microbiome analyses of blood and tissues suggest cancer diagnostic approach

Systematic characterization of the cancer microbiome provides the opportunity to develop techniques that exploit non-human, microorganism-derived molecules in the diagnosis of a major human disease. Following recent demonstrations that some types of cancer show substantial microbial contributions1-10, we re-examined whole-genome and whole-transcriptome sequencing studies in The Cancer Genome Atlas11 (TCGA) of 33 types of cancer from treatment-naive patients (a total of 18,116 samples) for microbial reads, and found unique microbial signatures in tissue and blood within and between most major types of cancer. These TCGA blood signatures remained predictive when applied to patients with stage Ia-IIc cancer and cancers lacking any genomic alterations currently measured on two commercial-grade cell-free tumour DNA platforms, despite the use of very stringent decontamination analyses that discarded up to 92.3% of total sequence data. In addition, we could discriminate among samples from healthy, cancer-free individuals (n = 69) and those from patients with multiple types of cancer (prostate, lung, and melanoma; 100 samples in total) solely using plasma-derived, cell-free microbial nucleic acids. This potential microbiome-based oncology diagnostic tool warrants further exploration.

Expression of antibody-drug conjugates (ADC) biomarkers in colorectal cancer

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Background: Multiple ADCs are in clinical trials for CRC and the optimal strategy for selecting patients who may benefit from the treatment is evolving. Due to the unique mechanism of ADCs, patient selection should involve screening not only for the presence of the antibody target, but also for markers of resistance or response to the payload. We have built a multiplexed ADC biomarker panel in FFPE tumor tissue that simultaneously quantifies the protein levels of the antibody targets and also the payload markers. Methods: FFPE tumor tissues from 363 CRC patients were microdissected and solubilized for mass spectrometry-based targeted proteomic analysis in our CLIA certified laboratory. We quantified protein levels of EGFR, HER2, HER3, Axl, Mesothelin, FRalpha, Trop2 (antibody targets), tubulin-beta3 and TOPO1 (payload resistance and response markers, respectively) simultaneously. The multiplexed assay also quantified additional 22 clinically relevant proteins. Results: Expression of EGFR(83%), HER2(52%), HER3(21.5%), Axl(3.7%), Mesothelin(26.5%), FRalpha(3.7%), and Trop2(59.8%) may indicate likely response to ADCs. Expression of TUBB3(+) and TOPO1 (>1350amol/µg) in antibody target-positive subset may suggest resistance or response to payloads, such as taxanes and irinotecan, respectively (Table). Previously we identified that HER2 expression >750amol/µg correlated with HER2 positivity. Accordingly, 1.4% (5/355) of CRC patients were HER2 positive, of which 40% (2/5) had TOPO1 expression >1350amol/µg (75th percentile) suggesting that these 2 patients may receive benefit from a HER2/TOPO1 ADC. (+) indicates expression ≥LOQ; (-) indicates expression <LOQ. Conclusions: In patients with CRC, quantitative proteomics identified both antibody targets and markers of resistance or response to the payloads for multiple approved and investigational ADC therapies.

[Table: see text]

Integrating multiple “omics” analyses, on a triage concept, for effective case selection followed by diagnostic colonoscopy

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Background: Implementation of population screening for colorectal cancer (CRC) before colonoscopy can reduce the challenge of the overall capacity of bowel examination and improve survival. Blood based CRC assessment biomarkers, on a triage concept, can lead to improved selection to colonoscopy and cost-effective CRC care. Methods: Innovative multi-omics approaches, with global and targeted LCMS data production (metabolomics, lipidomics, and 2D proteomics) and integrative data analytics, were applied to discover serological biomarkers to assess nonadvanced adenoma and identify stage I/II colorectal bowel lesions. A cohort of 2396 normal, 660 adenoma, 953 stage I, and 101 stage II blood samples, was constructed to discover screening biomarkers to support case finding of patients at high risk for nonadvanced adenoma and stage I/II cancer for subsequent diagnostic colonoscopy. Results: A three-analyte mProbe panel was constructed which outperformed the commercial assays of plasma methylated septin 9 and fecal Cologuard tests. Sensitivity: (1) nonadvanced adenoma–Cologuard 17.2%, mProbe 76.0%; (2) stage I-III-Cologuard 93.3%, stage I-II Septin 9 (ARUP laboratories) 77%, stage I-II mProbe: 92.3%. Specificity–Cologuard 89.8%, Septin 9 (ARUP laboratories) 88%, mProbe 90.7%. Conclusions: mProbe triage concept of a blood-based protein biomarker panel promises the precision to allow future CRC screening, and reduce the low-risk utilization of unnecessary, unpleasant and risk-associated bowel examinations.

Neurological Death is Common in Patients With EGFR Mutant Non-Small Cell Lung Cancer Diagnosed With Brain Metastases

Purpose

Brain metastases (BrM) are common in patients with epidermal growth factor receptor (EGFRm) mutant non-small cell lung cancer (NSCLC). We sought to determine the rate of neurologic death (ND) in this population.

Methods and Materials

We analyzed data from 198 patients who received a diagnosis of BrM from EGFRm NSCLC between 2004 and 2016, comparing patients whose initial treatment for BrM was stereotactic radiosurgery with or without tyrosine kinase inhibitors (TKI), whole brain radiation therapy (WBRT) with or without TKI, or TKI alone. The incidence of ND was determined using a competing risks analysis. Univariate and multivariate analyses were used to identify clinical variables associated with this outcome.

Results

The percentage of patients who initially received stereotactic radiosurgery, whole brain radiation therapy, or TKI alone was 22%, 61%, and 17%, respectively. Median overall survival in these subgroups was 31.1, 14.6, and 24.6 months, respectively (P = .0016). The 5-year incidence of ND among all patients was 40% and did not significantly vary according to treatment group. In a multivariable model, only leptomeningeal disease at any point in a patient’s disease course significantly correlated with ND (hazard ratio 4.75, P <.001).

Conclusions

Among our cohort of patients with BrM from EGFRm NSCLC, the incidence of ND was significantly higher than suggested by previous reports. BrM should be considered a driver of mortality in many patients with EGFRm NSCLC, and treatments providing better control of BrM, lower neurocognitive side effects, and maintenance of quality of life are needed.

Cognitive Trajectory Phenotypes in Human Immunodeficiency Virus-Infected Patients

OBJECTIVE

The presentation of cognitive impairments in HIV-infected individuals has transformed since the introduction of antiretroviral therapies. Although the overall prevalence of cognitive impairments has not changed considerably, frank dementia is now infrequent, and milder forms of cognitive impairments predominate. Mechanistic insights to the underlying causes of these residual cognitive impairments have been elusive, in part due to the heterogenous etiology of cognitive dysfunction in this population. Here, we sought to categorize longitudinal change in HIV-infected patients based on the performance in specific cognitive domains.

DESIGN

This study consisted of 193 participants from the CHARTER cohort with detailed demographic, clinical, and neuropsychological testing data obtained from 2 study visits interspersed by ∼6 months. Cognitive testing assessed executive function, learning and delayed recall, working memory, verbal fluency, speed of information processing, and motor skills. Change scores were calculated for each domain between the 2 study visits. Dimension reduction and clustering was accomplished by principal component analysis of change scores and k-means clustering to identify cognitive domains that group together and groups of subjects with similar patterns of change.

RESULTS

We identified 4 distinct cognitive change phenotypes that included declines in: (1) verbal fluency, (2) executive function (3) learning and recall, and (4) motor function, with approximately equal numbers of participants in each phenotype.

CONCLUSIONS

Each of the 4 cognitive change phenotypes identify deficits that imply perturbations in specific neural networks. Future studies will need to validate if cognitive change phenotypes are associated with alterations in associated neural pathways.

B-15 Engagement in Cognitively-Demanding Activities in Daily Life is Associated with Neurocognitive Test Performance and Perceived Cognitive Difficulties Among Adults With and Without HIV

Objective

Assessing daily activities is important for understanding how cognitive abilities affect everyday functioning. We evaluated a new measure capturing engagement in cognitively-demanding activities among people with and without HIV, and examined associations with neurocognitive test performance and perceived cognitive difficulties.

Method

Participants included 79 adults (59 HIV+, 20 HIV-) enrolled in studies at UCSD (mean age = 55.1; SD = 13.1). Domain-specific composite scaled scores measured neurocognitive functioning as continuous variables. Demographically-corrected global deficit scores determined neurocognitive impairment. Perceived cognitive difficulties were self-reported via the Everyday Cognition scale (ECog). The newly created, self-report Frequency and Difficulty of Activities Scale (FDAS) measured frequency of engagement in 27 cognitively-demanding activities [0 = Never to 10 = Once a day or more] in the last month. FDAS “total frequency score” sums all frequency ratings. Participants also rated difficulty performing each FDAS activity [0 = Not at all to 10 = Extremely]. FDAS “difficult-activity score” sums frequency ratings only for activities that participants identified as difficult for them (i.e., difficulty rating >75th percentile of sample).

Results

Higher FDAS total frequency scores correlated with better verbal fluency (r = 0.26, p = 0.019) and processing speed (r = 0.24, p = 0.030). Multiple regression revealed a significant interaction between cognitive impairment and frequency of engagement in difficult activities (b = 0.34, 95%CI = 0.18-0.50, p < 0.001), such that higher FDAS difficult-activity scores related to more perceived cognitive difficulties only among cognitively impaired participants.

Conclusion

This study explored use of a new measure of complex daily activities to aid neuropsychological interpretation. Results suggest that effects of neurocognitive impairment on perceived cognitive difficulties may only be apparent if individuals are attempting to perform challenging everyday tasks.

A-03 Ethnic/Racial Differences in Longitudinal Neurocognitive Change among People Living with HIV

HIV disproportionately affects Black and Latino people in the United States, but data on longitudinal neurocognitive patterns for these groups are scarce. This study evaluated the incidence and predictors of neurocognitive decline by ethnicity/race in a cohort of Black, Latino, and White people living with HIV (PLWH). Participants included 499 PLWH (43.5% White, 42.7% Black, 13.8% Latino; mean age at baseline = 43.5) from the six-site CNS HIV Anti-Retroviral Therapy Effects Research (CHARTER) study. Participants completed comprehensive neurocognitive and neuromedical evaluations over 3-7 study visits for an average of 2.8 years (SD = 1.1). Interpertation of neurocognitive change was based on published methods using regression-based norms that correct for baseline performance and practice effects. Survival analyses investigated the relationship between ethnicity/race and neurocognitive change, and predictors of neurocognitive decline. In follow-up, 108 participants (21.6%) declined, 311 (62.3%) remained stable, and 80 (16.0%) improved. In Cox proportional hazard models, hazard ratios for neurocognitive decline were increased for Latinos compared to Whites (HR = 2.19, 95%CI = 1.32-3.63, p = .002) and Blacks (HR = 1.87, 95%CI = 1.14-3.04, p = .01). Including significant covariates (baseline nadir CD4, hepatitis C Virus, and VACS Index: a composite marker of physical health among PLWH)did not significantly decrease the elevated risk for decline among Latinos. We found that Latino PLWH appear to have higher risk of neurocognitive decline compared to White and Black PLWH. Traditional markers of HIV disease and physical health at baseline did not explain this elevated risk of neurocognitive decline. Future research examining economic, socio-environmental, and culturally-relevant biomedical factors may help to explain this observed ethnic/racial disparity in longitudinal neurocognitive function in HIV.

B-24 Objective and Subjective Sleep Measures are Associated with Neurocognition in Middle-Aged and Older Adults With and Without HIV

Objective

Poorer sleep quality is related to worse cognitive functioning in the general population and people living with HIV; however, many studies use self-report sleep questionnaires that rely on retrospective recall. This study aimed to examine the relationship between objective (wrist actigraphy) and subjective sleep quality with neurocognitive functioning.

Method

Eighty-five adults aged 50-74 years with and without HIV (HIV+ n = 53, HIV- n = 32) were recruited from the community and ongoing studies at UC San Diego. Participants completed comprehensive neuropsychological testing assessing global and domain-specific cognition. Participants wore actigraphy watches for 14 nights after neuropsychological testing to objectively assess sleep quality (i.e., total sleep time (TST), efficiency, wake after sleep onset, and sleep fragmentation). The Pittsburgh Sleep Quality Index assessed subjective sleep quality.

Results

After adjusting for demographic variables and use of sleep medications, there were no differences in any sleep quality measures by HIV status (p’s>0.05). In separate adjusted linear regression models, lower sleep efficiency (p = 0.02; 95% CI: -9.5, -1.1) and greater sleep fragmentation (p = 0.02; 95% CI: -0.82, -0.09) were associated with worse learning. Less TST was associated with worse working memory (p = 0.02; 95% CI: -9.2, -0.8). In contrast, worse subjective sleep quality was associated with worse executive function (p < 0.01; 95% CI: -1.18, -0.23) and working memory (p = 0.03; 95% CI: -1.22, -0.07).

Conclusion

Both objective and subjective sleep quality were associated with cognition in both persons with and without HIV; however, subjective and objective sleep quality were associated with different cognitive domains. Therefore, both objective and subjective sleep quality are important health behaviors to assess.

Effect of daily supplementation with ubiquinol on muscle coenzyme Q10 concentrations in Thoroughbred racehorses

Coenzyme Q10 (CoQ10) is essential for mitochondrial aerobic production of ATP via oxidative phosphorylation, but has had little study in horses. Its biologically active form is ubiquinol. We evaluated the effects of daily supplementation with ubiquinol on gluteal muscle CoQ10 concentrations and an indicator of phosphorylation status, citrate synthase (CS), in fit Thoroughbreds. Six horses received either 1 g ubiquinol daily for 3 weeks followed by 21 days without supplement, or had a 3 week unsupplemented period followed by 3 weeks of supplementation. A seventh horse received the same diet as the other horses, but no supplement, and served as a negative control. Middle gluteal muscle biopsies were obtained before feeding at day 0 (baseline), and after 10 and 21 days of each period. Muscle CoQ10 concentration was determined by HPLC with UV detection at 275 nm. CS was measured spectrophotometrically at 37 °C and related to mitochondrial CoQ10 concentration. Results (mean ± standard deviation) were analysed by 2-way RM ANOVA for effects of supplementation and time (P<0.05). Muscle baseline and non-supplemented CoQ10 concentrations prior to beginning supplementation were not different (458±156 pmol/mg protein). Values increased from 413±276 (baseline) to 977±227 pmol/mg after 10 days supplementation (P=0.03), but not thereafter (21 days: 867±194 pmol/mg; P=0.31). CS activity increased in concert with CoQ10 concentration (P=0.02; baseline: 67±18, 10 days: 155±68, 21 days: 163±78 nmol/(min.mg)). Muscle CoQ10 concentration was strongly correlated with CS activity (P=0.002; r2=0.53). Discontinued supplementation decreased muscle CoQ10 concentration and tended towards significance (P=0.06). Daily dietary supplementation with 1 g ubiquinol increased gluteal muscle [CoQ10] from day 0 to day 10, but not from days 10 to 21, possibly indicating saturation of mitochondria with ubiquinol. Associated increases in CS activity suggested aerobic metabolic capacity was enhanced with supplementation. Discontinuing supplementation decreased CoQ10 concentration.

Self-initiated continuation of and adherence to HIV pre-exposure prophylaxis (PrEP) after PrEP demonstration project roll-off in men who have sex with men: associations with risky decision making, impulsivity/disinhibition, and sensation seeking

The objective of this study was to examine differences in the levels of risky decision making and other frontal system behavior constructs in relation to self-initiated continuance of HIV pre-exposure prophylaxis (PrEP) and PrEP adherence outcomes among men who have sex with men (MSM) following completion of a clinical PrEP trial. At the last PrEP trial visit, study provided PrEP was discontinued and participants were navigated to the community for PrEP continuation. In this cross-sectional analysis, 84/187 (45%) MSM who completed a prospective observational post-PrEP trial follow-up visit at the University of California San Diego were included. PrEP adherence was measured using dried blood spot tenofovir diphosphate (TFV-DP) levels. Risky decision making was assessed using the Iowa Gambling Task (IGT) and the Balloon Analogue Risk Task (BART), while impulsivity/disinhibition, sensation seeking, and substance use were assessed via standardized self-report questionnaires. A total of 58/84 (69%) of MSM who completed the 12-month post-study visit continued PrEP. Of those, n = 46 (79%) reached TFV-DP levels associated with adequate adherence. Individuals who elected to continue PrEP 12 months post-trial had riskier decision making on BART, but less impulsivity/disinhibition compared to individuals who did not continue PrEP. Neither risky decision making nor impulsivity/disinhibition/sensation seeking nor substance use correlated with PrEP adherence. Our findings suggest that those with risky decision making may have greater insight into their HIV risks, and therefore be more likely to continue to use PrEP. However, elevated impulsivity/disinhibition, indicative of greater neurobehavioral alterations, was negatively associated with PrEP continuance and is a potential target for future interventions to help people link to PrEP.

Seasonal variations in measurements of linear accelerator output

PURPOSE

Seasonal trends in linear accelerator output have been reported by at least one institution and data have suggested that they may be present at our center as well. The purpose of this work was to characterize these trends and determine whether local environmental conditions within the treatment rooms may be impacting the linear accelerators and/or the quality control (QC) dosimeter.

METHODS

Runtime plots of daily output data, acquired using an in-house ion chamber-based device, over 3 yr and for 15 linear accelerators of different makes and models were reviewed and evaluated. Environmental conditions were monitored prospectively in a representative treatment room for approximately 9 months and evaluated for correlations with output trends. Independent measures of output using daily MV portal images were compared with output measurements using the ion chamber-based device. A separate controlled experiment probing the response of the in-house dosimeter to humidity changes over time was also carried out using a constant current source and a small enclosure.

RESULTS

Runtime plots of output revealed sinusoidal, seasonal variations that were consistent across all treatment units, irrespective of manufacturer, model, or age of machine. The amplitude of the variation was on the order of 1% and maintained a yearly period. The independent measure of output using MV portal images did not corroborate the seasonal trends observed with the daily QC dosimeter. Based on the controlled experiment, the QC dosimeter was found to have a dependence on relative humidity changes, decreasing 1% in output per 30% increase in relative humidity.

CONCLUSIONS

Results confirm the presence of underlying seasonal variations in measured output from the linear accelerators. The findings identify humidity impact on the measurement device as the underlying cause of the cyclical changes and not the accelerators themselves. These results could help minimize unwarranted machine servicing.

Generalizability of demographically corrected Zambian neuropsychological norms to South African women

Objective: Demographically corrected norms typically account for the effects of age, education, and in some cases, sex and other factors (e.g. race/ethnicity). However, generalizability of normative standards to different countries and ethnic groups is not universal. This study sought to determine whether demographically specific Zambian neuropsychological norms would generalize to a group of South African women.Method: 212 English-Xhosa bilingual, South African (SA) women were administered a comprehensive neuropsychological (NP) test battery in either English or Xhosa. We examined rates of "impairment" using Global Deficit Scores (GDS) based upon published, demographically corrected norms from a nearby African country (Zambia). Using multiple regression, we examined the extent to which Zambian norms "corrected" for the effects of age and education in this SA sample.Results: Compared to the normative standards from Zambia, the South African women performed somewhat worse than expected on a few test measures and better than expected on others, but their GDS and associated "impairment" rates were close to what was seen in Zambia. Demographically corrected Zambian norms adequately adjusted for the effects of age and years of education in this sample of SA women, with the exception that Zambian norms appeared to "under correct" for the positive effects of years of education on tests of information processing speed.Conclusions: Demographically corrected norms developed for Zambia may adequately adjust for the effects of age in SA women. Further research is needed to determine whether additional corrections for education are needed in SA, especially for tests of information processing speed.