Digital spatial profiling of melanoma shows CD95 expression in immune cells is associated with resistance to immunotherapy

Although immune checkpoint inhibitor (ICI) therapy has dramatically improved outcome for metastatic melanoma patients, many patients do not benefit. Since adverse events may be severe, biomarkers for resistance would be valuable, especially in the adjuvant setting. We performed high-plex digital spatial profiling (DSP) using the NanoString GeoMx® on 53 pre-treatment specimens from ICI-treated metastatic melanoma cases. We interrogated 77 targets simultaneously in four molecular compartments defined by S100B for tumor, CD68 for macrophages, CD45 for leukocytes, and nonimmune stromal cells defined as regions negative for all three compartment markers but positive for SYTO 13. For DSP validation, we confirmed the results obtained for some immune markers, such as CD8, CD4, CD20, CD68, CD45, and PD-L1, by quantitative immunofluorescence (QIF). In the univariable analysis, 38 variables were associated with outcome, 14 of which remained significant after multivariable adjustment. Among them, CD95 was further validated using multiplex immunofluorescence in the Discovery immunotherapy (ITX) Cohort and an independent validation cohort with similar characteristics, showing an association between high levels of CD95 and shorter progression-free survival. We found that CD95 in stroma was associated with resistance to ICI. With further validation, this biomarker could have value to select patients that will not benefit from immunotherapy.

Phase II Window Study of Olaparib Alone or with Cisplatin or Durvalumab in Operable Head and Neck Cancer

Purpose

We conducted a phase II randomized noncomparative window of opportunity (WOO) trial to evaluate the inhibition of cellular proliferation and the modulation of immune microenvironment after treatment with olaparib alone or in combination with cisplatin or durvalumab in patients with operable head and neck squamous cell carcinoma (HNSCC).

Experimental Design

Forty-one patients with HNSCC were randomized to cisplatin plus olaparib (arm A), olaparib alone (arm B), no treatment (arm C) or durvalumab plus olaparib (arm D). The primary endpoint was to evaluate the percentage of patients in each arm that achieved a reduction of at least 25% in Ki67. Secondary endpoints included objective response rate (ORR), safety, and pathologic complete response (pCR) rate. Paired baseline and resection tumor biopsies and blood samples were evaluated for prespecified biomarkers.

Results

A decrease in Ki67 of at least 25% was observed in 44.8% of treated patients, as measured by quantitative immunofluorescence. The ORR among treated patients was 12.1%. pCR was observed in 2 patients. Two serious adverse events occurred in 2 patients.Programmed death ligand 1 (PD-L1) levels [combined positive score (CPS)] were significantly higher after treatment in arms A and D. Expression of CD163 and colony-stimulating factor 1 receptor (CSF1R) genes, markers of M2 macrophages, increased significantly posttreatment whereas the expression of CD80, a marker of M1 macrophages, decreased.

Conclusion

Preoperative olaparib with cisplatin or alone or with durvalumab was safe in the preoperative setting and led to decrease in Ki67 of at least 25% in 44.8% of treated patients. Olaparib-based treatment modulates the tumor microenvironment leading to upregulation of PD-L1 and induction of protumor features of macrophages.

Significance

HNSCC is characterized by defective DNA repair pathways and immunosuppressive tumor microenvironment. PARP inhibitors, which promote DNA damage and "reset" the inflammatory tumor microenvironment, can establish an effective antitumor response. This phase II WOO trial in HNSCC demonstrated the immunomodulatory effects of PARP inhibitor-induced DNA damage. In this chemo-naïve population, PARP inhibitor-based treatment, reduced tumor cell proliferation and modulated tumor microenvironment. After olaparib upregulation of PD-L1 and macrophages, suggests that combinatorial treatment might be beneficial.

Synopsis

Our WOO study demonstrates that preoperative olaparib results in a reduction in Ki67, upregulation of PD-L1 CPS, and induction of protumor features of macrophages in HNSCC.

Tissue Age Affects Antigenicity and Scoring for the 22C3 Immunohistochemistry Companion Diagnostic Test

Programmed death-ligand 1 (PD-L1) antibody 22C3 is the approved companion diagnostic immunohistochemistry test for treatment with pembrolizumab and cemiplimab in multiple cancer types. The 22C3 and 28-8 antibodies target the extracellular domain (ECD) of PD-L1, which is known to contain N-glycosylation sites. We hypothesize that antigenicity could be affected by the degradation of the glycan part of the epitope and thus change the scoring of the assay over time. Here, we test samples over time and assess the effects of time and deglycosylation on PD-L1 signal by comparing an antibody with an ECD antigen to an antibody with an intracellular domain (ICD) antigen. Ten whole-tissue sections of non-small-cell lung cancer (NSCLC) from 2018 were selected for testing. Fresh-cut serial sections for each case were stained on DAKO Link48 for 22C3 according to the label. In parallel, a previously described laboratory-developed test using E1L3N (an ICD antibody) was performed on the Leica BondRX. Tumor proportion scores for 22C3 and E1L3N were read by a pathologist and compared to the previous clinical diagnoses. To determine the effect using a quantitative approach, a tissue microarray (TMA) cohort with 90 NSCLC cases was similarly assessed. Finally, to determine whether the possible effect of epitope glycosylation, antibodies were tested before and after enzymatic deglycosylation of specimens. We found that 6 of 7 archival positive samples showed a significant reduction in positive staining with 22C3 compared to the original diagnostic sample assessed 3 years earlier. In an older archival TMA cohort, a quantitative significant difference in signal intensity was noted when staining with 22C3 was compared to E1L3N. This loss of signal was not noted in the fresh cell line TMA consistent with a time-dependent degradation of staining. Finally, quantitative assessment of the fresh TMA showed a significant loss of signal after a deglycosylation procedure when stained with 22C3, which was not seen when stained with E1L3N. We believe that these data show that the glycan part of the 22C3 epitope is not stable over time, and that this issue should be considered when assessing archival tissue for diagnostic or research purposes.

Domestic Violence Housing First Model and Association With Survivors' Housing Stability, Safety, and Well-being Over 2 Years

Importance

Intimate partner violence (IPV) is a leading cause of homelessness and a serious threat to public health and well-being.

Objective

To determine whether the Domestic Violence Housing First (DVHF) model improves safety, housing stability, and mental health over 2 years.

Design, Setting, and Participants

This longitudinal comparative effectiveness study interviewed IPV survivors and reviewed their agency records. All unstably housed or homeless IPV survivors entering domestic violence (DV) services were eligible to participate in the study, ensuring capture of typical variability in service delivery (eg, some survivors would enter services when agencies had the capacity to provide DVHF and others would receive services as usual [SAU]). Clients from 5 DV agencies (3 rural and 2 urban) referred by agency staff in a Pacific Northwest state of the United States were assessed between July 17, 2017, and July 16, 2021. Interviews were conducted in English or Spanish at entry into services (baseline) and at 6-, 12-, 18-, and 24-month follow-up visits. The DVHF model was compared with SAU. The baseline sample included 406 survivors (92.7% of 438 eligible). Of the 375 participants retained at the 6-month follow-up (92.4% retention), 344 had received services and had complete data across all outcomes. Three hundred sixty-three participants (89.4%) were retained at the 24-month follow-up.

Intervention

The DVHF model has 2 components: housing-inclusive advocacy and flexible funding.

Main Outcomes and Measures

Main outcomes included housing stability, safety, and mental health, which were assessed using standardized measures.

Results

Of the 344 participants (mean [SD] age, 34.6 [9.0] years) included in the analyses, 219 (63.7%) received DVHF and 125 (36.3%) received SAU. Most participants identified as female (334 [97.1%]) and heterosexual (299 [86.9%]). Two hundred twenty-one participants (64.2%) were from a racial and ethnic minority group. Longitudinal linear mixed-effects models showed that receiving SAU was associated with greater housing instability (mean difference, 0.78 [95% CI, 0.42-1.14]), DV exposure (mean difference, 0.15 [95% CI, 0.05-0.26]), depression (mean difference, 1.35 [95% CI, 0.27-2.43]), anxiety (mean difference, 1.15 [95% CI, 0.11-2.19]), and posttraumatic stress disorder (mean difference, 0.54 [95% CI, 0.04-1.04]) compared with receiving the DVHF model.

Conclusions and Relevance

Evidence in this comparative effectiveness study suggests that the DVHF model was more effective than SAU in improving the housing stability, safety, and mental health of survivors of IPV. The DVHF's amelioration of all of these interconnected public health issues-relatively quickly and with long-term continuance-will be of substantial interest to DV agencies and others working to support unstably housed IPV survivors.

Multi-Institutional Study of Pathologist Reading of the Programmed Cell Death Ligand-1 Combined Positive Score Immunohistochemistry Assay for Gastric or Gastroesophageal Junction Cancer

The assessment of the expression of programmed cell death ligand-1 (PD-L1) using immunohistochemistry (IHC) has been controversial since its introduction. The methods of assessment and the range of assays and platforms contribute to confusion. Perhaps the most challenging aspect of PD-L1 IHC is the combined positive score (CPS) method of interpretation of IHC results. Although the CPS method is prescribed for more indications than any other PD-L1 scoring system, its reproducibility has never been rigorously assessed. In this study, we collected a series of 108 gastric or gastroesophageal junction cancer cases, stained them using the Food and Drug Administration-approved 22C3 assay, scanned them, and then circulated them to 14 pathologists at 13 institutions for the assessment of interpretative concordance for the CPS system. We found that higher cut points (10 or 20) performed better than a CPS of <1 or >1. We used the Observers Needed to Evaluate Subjective Tests algorithm to assess how the CPS system might perform in the real-world setting and found that the cut points of <1 or >1 showed an overall percent agreement of only 30% among the pathologist raters, with a plateau occurring at 8 raters. The raters performed better at higher cut points. However, the best cut point of <20 versus that of >20 was still disappointing, with a plateau at an overall percent agreement of 70% (at 7 raters). Although there is no ground truth for CPS, we compared the score with quantitative messenger RNA measurement and showed no relationship between the score (at any cut point) and messenger RNA amount. In summary, we showed that CPS shows high subjective variability among pathologist readers and is likely to perform poorly in the real-world setting. This system may be the root cause of the poor specificity and relatively low predictive value of IHC companion diagnostic tests for PD-1 axis therapies that use the CPS system.

Digital Spatial Profiling Links Beta-2-microglobulin Expression with Immune Checkpoint Blockade Outcomes in Head and Neck Squamous Cell Carcinoma

Programmed cell death protein-1 (PD-1)-targeted immunotherapy is approved for recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) treatment. Although its efficacy correlates with PD-L1 expression, response is limited even among positive cases. We employed digital spatial profiling (DSP) to discover potential biomarkers of immunotherapy outcomes in HNSCC. Fifty prospectively collected, pretreatment biopsy samples from patients with anti-PD-1-treated R/M HNSCC, were assessed using DSP, for 71 proteins in four molecularly defined compartments (tumor, leukocyte, macrophage, and stroma). Markers were evaluated for associations with progression-free (PFS) and overall survival (OS). High beta-2 microglobulin (B2M), LAG-3, CD25, and 4-1BB in tumor; high B2M, CD45, CD4 in stroma, and low fibronectin in the macrophage compartment, correlated with prolonged PFS. Improved PFS and OS were observed for cases with high B2M by quantitative and mRNA. Findings were validated in an independent cohort for PFS (HR, 0.41; 95% confidence interval, 0.19-0.93; P = 0.034). B2M-high tumors showed enrichment with immune cell and immune checkpoint markers. Our study illustrates B2M expression is associated with improved survival for immune checkpoint inhibitor (ICI)-treated HNSCC.

Significance

In the current study, DSP revealed the positive association of B2M expression in the tumor compartment with immunotherapy outcomes in R/M HNSCC.

Quantitative, Spatially Defined Expression of Leukocyte-associated Immunoglobulin-like Receptor in Non-small Cell Lung Cancer

Targeting the interaction of leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) and its ligands has been shown to reinstate antitumor immunity. In addition, the introduction of the LAIR-1 decoy protein, LAIR-2, sensitizes previously resistant lung tumors to programmed death-1 (PD-1) blockade, indicating the potential of LAIR-1 as an alternative marker for anti-PD-1 resistance in lung cancer. Here, we assessed LAIR-1 as compared with programmed death-ligand 1 (PD-L1) expression in various tumors, with a focus on non-small cell lung cancer (NSCLC) and its histologic subtypes using multiplexed quantitative immunofluorescence (mQIF) in 287 (discovery cohort) and 144 (validation cohort) patients with NSCLC. In addition, using multispectral imaging technology on mQIF images, we evaluated the localization of LAIR-1 on various cell types. We observed that CD14+, CD68+, and CD163+ monocytes and CK+ tumor cells predominantly expressed LAIR-1 more than other cell types. Furthermore, LAIR-1 expression in the tumor compartment was significantly higher in patients with lung adenocarcinoma (LUAD) than those with lung squamous cell carcinoma subtype (**, P = 0.003). Our results indicated that high tumor LAIR-1 expression in patients with LUAD is negatively associated with OS (overall survival, HR = 2.4; *, P = 0.02) highlighting its prognostic value in LUAD but not in other subtypes. The Pearson correlation between LAIR-1 and PD-L1 is 0.31; however, mutual exclusive staining pattern (i.e., several cases were positive for LAIR-1 and negative for PD-L1) was observed. Altogether, our data suggest that the combination therapy of anti-PD-1/PD-L1 with anti-LAIR-1 or the anti-LAIR-1 monotherapy alone may be promising cancer immunotherapeutic strategies.

Significance

The spatial, quantitative assessment of LAIR-1 in NSCLC shows positive association of OS with high LAIR-1+/CD68+ cell densities and negative association of OS with high LAIR-1 expression in LUAD tumor subtype.

Multi-institutional Assessment of Pathologist Scoring HER2 Immunohistochemistry

The HercepTest was approved 20+ years ago as the companion diagnostic test for trastuzumab in human epidermal growth factor 2 (HER2) or ERBB2 gene-amplified/overexpressing breast cancers. Subsequent HER2 immunohistochemistry (IHC) assays followed, including the now most common Ventana 4B5 assay. Although this IHC assay has become the clinical standard, its reliability, reproducibility, and accuracy have largely been approved and accepted on the basis of concordance among small numbers of pathologists without validation in a real-world setting. In this study, we evaluated the concordance and interrater reliability of scoring HER2 IHC in 170 breast cancer biopsies by 18 breast cancer-specialized pathologists from 15 institutions. We used the Observers Needed to Evaluate Subjective Tests method to determine the plateau of concordance and the minimum number of pathologists needed to estimate interrater agreement values for large numbers of raters, as seen in the real-world setting. We report substantial discordance within the intermediate categories (<1% agreement for 1+ and 3.6% agreement for 2+) in the 4-category HER2 IHC scoring system. The discordance within the IHC 0 cases is also substantial with an overall percent agreement (OPA) of only 25% and poor interrater reliability metrics (0.49 Fleiss' kappa, 0.55 intraclass correlation coefficient). This discordance can be partially reduced by using a 3-category system (28.8% vs 46.5% OPA for 4-category and 3-category scoring systems, respectively). Observers Needed to Evaluate Subjective Tests plots suggest that the OPA for the task of determining a HER2 IHC score 0 from not 0 plateaus statistically around 59.4% at 10 raters. Conversely, at the task of scoring HER2 IHC as 3+ or not 3+ pathologists' concordance was much higher with an OPA that plateaus at 87.1% with 6 raters. This suggests that legacy HER2 IHC remains valuable for finding the patients in whom the ERBB2 gene is amplified but unacceptably discordant in assigning HER2-low or HER2-negative status for the emerging HER2-low therapies.

Exercise unmasks impaired vascular and cardiac hemodynamic in patients with hypertrophic cardiomyopathy

Background/Introduction

Exertional dyspnea is a common finding in patients with Hypertrophic Cardiomyopathy (HCM), yet little data is available regarding the hemodynamic disturbances that lead to symptom development in this population.

Purpose

To investigate the mechanisms involved in the functional limitation of patients with HCM.

Methods

We prospectively studied 20 symptomatic patients with confirmed diagnosis of HCM. Assessment included NT-pro BNP levels, echocardiogram, and invasive characterization, where subjects also underwent invasive cardiopulmonary exercise testing.

Results

Median patient age was 57 (48–66) years old and 15 (75%) were male. Basal NT-pro BNP was elevated (748 pg/mL [406–1082]) and 8 (40%) subjects had NYHA functional Class III despite optimal medical treatment. Sarcomeric abnormal mutations were identified in 12 subjects (60%), most frequently in MYBPC3. Ultrasound imaging showed marked left ventricle (LV) hypertrophy (LV Mass Index 140 g/m2 [109–161]), with signs of LV outflow obstruction in 13 (65%) subjects. All patients displayed preserved ejection fraction (68% [61–73]). Significant mitral regurgitation was present in 5 subjects and median E/e' was 9.87 [6.43–13.14].

At rest, biventricular filling pressures were relatively normal, with upper limit mean Pulmonary Pressure (Table). Patients exercised for 6.4 (95% CI: 5.6–7.2) min, achieving a respiratory exchange ratio of 1.11 (1.02–1.17). All subjects displayed normal cardiac output at rest (5.6 L/min (3.7–7.5)), that increased during exertion, due mostly to a rise in heart rate (p&lt;0.0001). Exercise doubled LV End-Diastolic Pressure from 15.3 (11.5–19.1) mmHg at baseline to 30.4 (26.6–34.3) mmHg at peak VO2 (p&lt;0.0001), whereas mean pulmonary pressure increased from 21 (14–29) mmHg to 40 (33–47) mmHg (p&lt;0.0001).

Remarkably, although arterial hemodynamics were relatively normal at baseline, exercise induced significant increases both in the continuous (systemic vascular resistance) and pulsatile components of vascular load (Impedances, p&lt;0.05; Table 1) (Figure 1). This increase in afterload during exertion has not been previously documented in HCM. The decreased compliance derived, can also play a role in the elevated filling pressures documented on exertion.

Conclusion

Exercise unmasks adverse hemodynamics in HCM, severely increasing LV filling pressures and showing systemic arterial dysfunction.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III, Spain.

Quantitative measurement of HER2 expression to subclassify ERBB2 unamplified breast cancer

The efficacy of the antibody drug conjugate (ADC) Trastuzumab deruxtecan (T-DXd) in HER2 low breast cancer patients suggests that the historical/conventional assays for HER2 may need revision for optimal patient care. Specifically, the conventional assay is designed to distinguish amplified HER2 from unamplified cases but is not sensitive enough to stratify the lower ranges of HER2 expression. Here we determine the optimal dynamic range for unamplified HER2 detection in breast cancer and then redesign an assay to increase the resolution of the assay to stratify HER2 expression in unamplified cases. We used the AQUA™ method of quantitative immunofluorescence to test a range of antibody concentrations to maximize the sensitivity within the lower range of HER2 expression. Then, using a cell line microarray with HER2 protein measured by mass spectrometry we determined the amount of HER2 protein in units of attomols/mm². Then by calculation of the limits of detection, quantification, and linearity of this assay we determined that low HER2 range expression in unamplified cell lines is between 2 and 20 attomol/mm². Finally, application of this assay to a serial collection of 364 breast cancer cases from Yale shows 67% of the population has HER2 expression above the limit of quantification and below the levels seen in HER2 amplified breast cancer. In the future, this assay could be used to determine the levels of HER2 required for response to T-DXd or similar HER2 conjugated ADCs.

Evaluating diversity, equity, and inclusion consultation requests

Diversity, equity, and inclusion (DEI) efforts have increased drastically as companies and institutions recognize their value in fostering innovative ideas for success. Individuals trained in these efforts can impart their knowledge and expertise in consultation, but this transaction should be mutually beneficial. Here, we provide recommendations to maximize consulting opportunities.

Shadow mentoring: a cost-benefit review for reform

Shadow mentoring relationships are those outside of traditional mentoring roles and are an unseen yet critical component of trainee retention that is rarely acknowledged. In this paper, we detail the costs and benefits of shadow mentoring and propose mechanisms to ensure that shadow mentoring is acknowledged as a vital contribution to scientific communities.

Discovery of Biomarkers of Resistance to Immune Checkpoint Blockade in NSCLC Using High-Plex Digital Spatial Profiling

INTRODUCTION

Despite the clinical efficacy of immune checkpoint inhibitors (ICIs) in NSCLC, only approximately 20% of patients remain disease-free at 5 years. Here, we use digital spatial profiling to find candidate biomarker proteins associated with ICI resistance.

METHODS

Pretreatment samples from 56 patients with NSCLC treated with ICI were analyzed using the NanoString GeoMx digital spatial profiling method. A panel of 71 photocleavable oligonucleotide-labeled primary antibodies was used for protein detection in four molecular compartments (tumor, leukocytes, macrophages, and immune stroma). Promising candidates were orthogonally validated with quantitative immunofluorescence. Available pretreatment samples from 39 additional patients with NSCLC who received ICI and 236 non-ICI-treated patients with operable NSCLC were analyzed to provide independent cohort validation.

RESULTS

Biomarker discovery using the protein-based molecular compartmentalization strategy allows 284 protein variables to be assessed for association with ICI resistance by univariate analysis using continuous log-scaled data. Of the 71 candidate protein biomarkers, CD66b in the CD45+CD68 molecular compartment (immune stroma) predicted significantly shorter overall survival (OS) (hazard ratio [HR] 1.31, p = 0.016) and was chosen for validation. Orthogonal validation by quantitative immunofluorescence illustrated that CD66b was associated with resistance to ICI therapy but not prognostic for poor outcomes in untreated NSCLC (discovery cohort [OS HR 2.49, p = 0.026], validation cohort [OS HR 2.05, p = 0.046], non-ICI-treated cohort [OS HR 1.67, p = 0.06]).

CONCLUSIONS

Using the technique, we have discovered that CD66b expression is indicative of resistance to ICI therapy in NSCLC. Given that CD66b identifies neutrophils, further studies are warranted to characterize the role of neutrophils in ICI resistance.

PD-L1 and PD-L2 mRNA measured using closed system qRT-PCR are associated with outcome and high negative predictive value in immunotherapy-treated non-small cell lung cancer

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have become standard of care in lung cancer management, but only a relatively small percentage of patients treated respond. Current predictive biomarkers, including immunohistochemical (IHC) detection of PD-L1, are insufficient for determining who will respond or, more importantly in the adjuvant setting, who will not respond to ICI therapy. Here, we investigate an alternative method of assessment of PD-L1 to predict non-response.

METHODS

This study utilizes a research use only quantitative real-time reverse transcription polymerase chain reaction assay on the GeneXpert® (GX) system, to test for the association between 4 target immune genes, CD274 (PD-L1), PDCD1LG2 (PD-L2), CD8A, and IRF1, and response to ICI therapy. Tissues were collected from 122 patients with advanced non-small cell lung cancer prior to ICI therapy in a retrospective cohort, macro-dissected, and analyzed using the GX.

RESULTS

Both high PD-L1 and PD-L2 mRNA expression levels were associated with improved long-term benefit at 24 months (p=0.047 for both PD-L1 and PD-L2) and overall survival (PD-L1, p= 0.048; PD-L2 p= 0.049). Both PD-L1 and PD-L2 mRNA levels were higher in patients with KRAS mutations. Most importantly, low PD-L1 mRNA showed a high negative predictive value of 0.92 for absence of long-term benefit.

CONCLUSIONS

With further validation this assay in low stage patients, assessment of PD-L1 mRNA rather than protein, could be a method to determine which low stage patients should not be treated with ICIs in the adjuvant setting. This approach may also be a useful objective method for selecting patients for treatment in the advanced setting.

Abstract 1242: PD-L1 and PD-L2 mRNA are associated with outcome and high negative predictive value in immunotherapy-treated non-small cell lung cancer

Background: Immune checkpoint inhibitors (ICIs) are a class of immunotherapy that enhance a patient’s anti-cancer immune response, but only a small percentage of patients who are treated respond. This means patients who do not respond undergo costly and side effect-inducing treatment for no benefit indicating a need for improved selection criteria. Current predictive biomarkers include immunohistochemical (IHC) detection of PD-L1 but are insufficient for determining who will respond or, more importantly in the adjuvant setting, who will not respond.

Methods: This study utilizes a research use only (RUO*) quantitative real-time reverse transcription polymerase chain reaction assay, the GeneXpert® (GX) PD-L1 panel prototype assay, to test for the association between 4 target immune genes, CD274 (PD-L1), PDCD1LG2 (PD-L2), CD8A, and IRF1, and response to ICI therapy. Tissues were collected from 122 patients with advanced non-small cell lung cancer prior to ICI therapy in a retrospective cohort, macro-dissected, and analyzed using the PD-L1 prototype assay. Lysates were run on the GX instrument using the PD-L1 prototype assay. Individual transcripts were quantitated for each sample and the association with response was assessed. Median mRNA expression was used as a cutpoint to look at survival, clinical response and positive and negative predictive value (PPV, NPV). Optimal cutpoint was determined using Rstudio to also assess PPV and NPV. This study was approved by Yale Human Investigation IRB protocol ID 9505008219.

Results: Both high PD-L1 and PD-L2 mRNA, defined by median, were associated with improved long-term benefit at 24-months (PD-L1, p=0.0416; PD-L2, p=0.0435) and overall survival (PD-L1, p=0.047; PD-L2, p=0.047). Furthermore, low PD-L1 mRNA, defined by optimal cutpoint, showed a negative predictive value of 0.92.

Conclusions: High PD-L1 and PD-L2 mRNA, measured by GX, are associated with improved long-term benefit and overall survival. Importantly, low PD-L1 mRNA has a high negative predictive value. Given the simplicity and reproducibility of the GX system, with further validation this assay could be an improved method for selecting patients for treatment in the advanced setting, or more importantly, to determine which low stage patients should not be treated in the adjuvant setting. *For research use only. Not for use in diagnostic procedures.

Citation Format: Aileen I. Fernandez, Niki Gavrielatou, Leena McCann, Saba Shafi, Myrto K. Moutafi, Sandra Martinez-Morilla, Ioannis Vathiotis, Thazin Nwe Aung, Vesal Yaghoobi, Yalai Bai, Jodi Weidler, Michael Bates, David L. Rimm. PD-L1 and PD-L2 mRNA are associated with outcome and high negative predictive value in immunotherapy-treated non-small cell lung cancer [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 1242.

Examination of Low ERBB2 Protein Expression in Breast Cancer Tissue

IMPORTANCE

Trastuzumab deruxtecan (T-DXd) has shown efficacy in patients with breast cancer with ERBB2 immunohistochemistry (IHC) scores of 1+ or 2+ but not 0 as read in central pathology laboratories. The drug is currently being tested in large randomized clinical trials with registration intent for this patient population.

OBJECTIVE

To determine the suitability of the current standard ERBB2 IHC assays to select patients with low ERBB2 positivity for treatment with T-DXd.

DESIGN AND SETTING

Assessment of data from College of American Pathologists surveys and assessment of analytic data from a Yale University-based study of concordance of 18 pathologists reading 170 breast cancer biopsies.

RESULTS

The total survey data set included scores over 2 years from 1391 to 1452 laboratories of 40 ERBB2 cores from each laboratory (20 cores twice a year for a total of 80). College of American Pathologists surveys show that 19% of cases read by the laboratories generate results with less than or equal to 70% concordance for IHC ERBB2 score 0 vs 1+. When 18 pathologists read the scanned slides from a selected set of breast cancer biopsies using a 4-point scale, there was only 26% concordance between 0 and 1+ compared with 58% concordance between 2+ and 3+.

CONCLUSIONS AND RELEVANCE

In this study using a current standard ERBB2 IHC assay, the scoring accuracy for ERBB2 IHC in the low range (0 and 1+) was poor. This inaccuracy in the real world could lead to misassignment of many patients for treatment with T-DXd.

Abstract P1-02-02: Examination of low Her2 expression in breast cancer

Introduction: Antibody-drug conjugates (ADC) are designed to effectively deliver cytotoxic agents directly to malignant cells. Trastuzumab deruxtecan (Tdx), an ADC of trastuzumab, an enzyme-cleavable linker, and a cytotoxic topoisomerase I inhibitor, has been shown to have antitumor activity in patients with breast cancer with low levels of HER2. However, current companion diagnostic tests for HER2-targetting therapies, immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH), were optimized for high (gene amplified) levels of HER2. We hypothesize that the current common assays used in clinic do not efficiently differentiate between patients whose cancers have “0” HER2 expression and “1+” HER2 expression and thus could miss patients who would benefit from treatment with this drug. Methods: Here, we evaluated two years of HER2 surveys from the College of American Pathologists’ (CAP) Proficiency Testing Surveys for HER2 expression in breast cancer from 2019 and 2020. Participating laboratories received two tissue microarrays (TMAs) of 10 breast cancer cores, each Laboratories stained for HER2 using the standard IHC assay used in their labs. The scores were returned to the CAP as part of their quality assessment program. Each survey dataset covers the scores from around 1400 labs of 20 cores each as well as supplemental questions regarding the methodology used. We summarized the relative frequency and distribution of each score given to every core. A second independent analytic dataset was selected from the archives of the Department of Pathology at Yale, from breast biopsies in 2018. The set, enriched in HER2 2+ and 3+ cases, was read by eighteen board-certified pathologists, most with over 5 years’ experience, participating in an interobserver variability study. Hematoxylin and eosin (H&E) and HER2 IHC digitally scanned images of 170 independent cases were provided. Pathologists scored the cases as 0,1, 2, or 3+. Fisher’s exact test was used to compare the 0/1+ concordant cases to 2+/3+ cases. All tests were two-sided at a significant level 0.05. Statistical analysis was performed using Graphpad Prism Version 9.0.1 and the dplyr package in R Version 1.0.143. This study was approved by Yale Human Investigation IRB protocol ID 9505008219. Results: We found that 65% of the 80 cores evaluated in the CAP survey (52/80) had a concordance rate ≥90%. This high concordance was limited to scores of 0 and 3+. The lowest concordance was found between 0 versus 1+. Of the 80 cores, 56 were considered negative (HER2 score of 0 or 1). In 25% of those cores there was &lt; 70% concordance (n=15; 6 in 2019 and 9 in 2020). Analytic concordance was assessed in the independent, Yale cohort where we found that of the 170 cases, 92 were read as 0 by at least one pathologist. Of these 92, 24 were concordant (26%), defined as a ≥90% agreement. In comparison, 45/170 were read as 3+ by at least one pathologist. Again,. using a 90%definition of concordance, 26 of 45 cases (58%) were concordant. Comparison of 0/1+ concordant cases versus 2+/3+ concordant cases showed a significant difference (χ2 = 12.07, p&lt;0.0005). Conclusions: Assessment of laboratory performance of around 1400 CAP labs using common current HER2 assays on CAP survey specimens, there is significant discordance in the evaluation of 0 vs. 1+ cases. In a separate selected breast biopsy cohort examined by 18 breast pathologists, we showed that discordance between scores of 0 vs 1+ is significantly larger than that between 2+ and 3+. Given the efficacy of T-DXd, we believe patients may be mis-assigned for treatment or no treatment if the decision depends on performance of the standard current HER2 assays.

Citation Format: Aileen I Fernandez, Matthew Liu, Andrew Bellizzi, Jane Brock, Oluwole Fadare, Krisztina Hanley, Malini Harigopal, Julie M. Jorns, M. Gabriela Kuba, Amy Ly, Mirna Podoll, Kimmie Rabe, Mary Ann Sanders, Kamaljeet Singh, Olivia L Snir, Rinda Soong, Shi Wei, Hannah Wen, Serena Wong, Esther Yoon, Lajos Pusztai, Emily Reisenbichler, David L. Rimm. Examination of low Her2 expression in breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-02-02.

Deep learning trained on hematoxylin and eosin tumor region of Interest predicts HER2 status and trastuzumab treatment response in HER2+ breast cancer

The current standard of care for many patients with HER2-positive breast cancer is neoadjuvant chemotherapy in combination with anti-HER2 agents, based on HER2 amplification as detected by in situ hybridization (ISH) or protein immunohistochemistry (IHC). However, hematoxylin & eosin (H&E) tumor stains are more commonly available, and accurate prediction of HER2 status and anti-HER2 treatment response from H&E would reduce costs and increase the speed of treatment selection. Computational algorithms for H&E have been effective in predicting a variety of cancer features and clinical outcomes, including moderate success in predicting HER2 status. In this work, we present a novel convolutional neural network (CNN) approach able to predict HER2 status with increased accuracy over prior methods. We trained a CNN classifier on 188 H&E whole slide images (WSIs) manually annotated for tumor Regions of interest (ROIs) by our pathology team. Our classifier achieved an area under the curve (AUC) of 0.90 in cross-validation of slide-level HER2 status and 0.81 on an independent TCGA test set. Within slides, we observed strong agreement between pathologist annotated ROIs and blinded computational predictions of tumor regions / HER2 status. Moreover, we trained our classifier on pre-treatment samples from 187 HER2+ patients that subsequently received trastuzumab therapy. Our classifier achieved an AUC of 0.80 in a five-fold cross validation. Our work provides an H&E-based algorithm that can predict HER2 status and trastuzumab response in breast cancer at an accuracy that may benefit clinical evaluations.

Quantitative assessment of the immune microenvironment in African American Triple Negative Breast Cancer: a case-control study

PURPOSE

Triple negative breast cancer (TNBC) is more common in African American (AA) than Non-AA (NAA) population. We hypothesize that tumor microenvironment (TME) contributes to this disparity. Here, we use multiplex quantitative immunofluorescence to characterize the expression of immunologic biomarkers in the TME in both populations.

PATIENTS AND METHODS

TNBC tumor resection specimen tissues from a 100-patient case: control cohort including 49 AA and 51 NAA were collected. TME markers including CD45, CD14, CD68, CD206, CD4, CD8, CD20, CD3, Ki67, GzB, Thy1, FAP, aSMA, CD34, Col4, VWF and PD-L1 we quantitatively assessed in every field of view. Mean expression levels were compared between cases and controls.

RESULTS

Although no significant differences were detected in individual lymphoid and myeloid markers, we found that infiltration with CD45+ immune cells (p = 0.0102) was higher in TNBC in AA population. AA TNBC tumors also had significantly higher level of lymphocytic infiltration defined as CD45+ CD14- cells (p = 0.0081). CD3+ T-cells in AA tumors expressed significantly higher levels of Ki67 (0.0066) compared to NAAs, indicating that a higher percentage of AA tumors contained activated T-cells. All other biomarkers showed no significant differences between the AA and NAA group.

CONCLUSIONS

While the TME in TNBC is rich in immune cells in both racial groups, there is a numerical increase in lymphoid infiltration in AA compared to NAA TNBC. Significantly, higher activated T cells seen in AA patients raises the possibility that there may be a subset of AA patients with improved response to immunotherapy.

Cohort of patients with hypertrophic cardiomyopathy and alpha tropomyosin 1 variants followed up at a national reference center

Background

Hypertrophic cardiomyopathy (HCM), the most common inherited cardiac condition, is mainly caused by pathogenic variants in sarcomeric genes. Alpha tropomyosin gene (TPM1) account for a small percentage (1–5%) of HCM cases with ∼20 relevant variants described so far related to this condition. However, TPM1–hypertrophic cardiomyopathy is thought to be associated with high rates of heart failure and sudden death (SD).

Purpose

To describe the phenotype and genotype of a cohort of adult and pediatric patients with HCM and variants in TPM1 followed up in an inherited cardiovascular disease program of a national reference center.

Methods

Patients with HCM and TPM1 variants potentially related to the phenotype were retrospectively identified. Genetic test was performed by next generation sequencing panels or clinical exome. Clinical data, any need of intervention (obstruction relief, device implantation, heart transplant) and major adverse cardiovascular events were collected from medical records. We performed co-segregation studies whenever possible. Predictive models in order to support the possible pathogenicity of the variants were also applied.

Results

We identified 13 individuals (54% females) from 11 families with HCM and variants in TPM1. 12 patients had phenotype and one was a carrier. 5 out of 12 patients (42%) were diagnosed before the age of 12 years, all with severe phenotype. The most frequent pattern was asymmetric septal hypertrophy, with a mean thickness of the septum of 22 mm (range 14–37). 4 cases were obstructive, of which 3 required surgical myectomy. 4 patients required an implanted cardiac defibrillator (ICD), all in childhood. One was in secondary prevention after an aborted SD in a 12-year-old girl. 3 appropriate therapies were recorded in 2 patients during follow-up. A girl underwent heart transplantation at the age of 12 because of angina at rest. At last evaluation 67% were symptomatic, with 3 patients in functional class II and 5 patients in functional class III-IV/IV.

8 missense variants in TPM1 were identified in the 11 families (table 1). All variants are described in Clinvar as variants of unknown significance (VUS). They appear at a very low frequency (&lt;0.01%) or are absent in general population and predictive models of protein structure and functionality (PreditProtein) indicate an impact on the structure of the protein, supporting their possible pathogenicity. Figure 1 shows a diagram of the variants position within TPM1 gen. Cossegregation data and the presence of the same variant in non_related families allowed us to reclassify 4 variants as “likely pathogenic”.

Conclusion

This study provides cosegregation data and “in silico” analysis of the potential functional impact of several TPM1 variants, supporting their pathogenicity. In our cohort, HCM related to TMP1 variants is associated with high penetrance (92%), early onset and poor clinical course in childhood and youth.

Funding Acknowledgement

Type of funding sources: None. Figure 1

Extracellular vesicles secreted by human cardiosphere-derived cells attenuate electrophysiological remodelling in an in vitro model of atrial fibrillation

Background

Stem cells and their secreted extracellular vesicles (EVs) have shown different cardioprotective effects. However, their impact on the electrophysiological properties of the heart tissue remains controversial. While the use of some progenitor cells seems to have antiarrhythmic potential, the use of cardiomyocyte-like cells may be proarrhythmic. The mechanisms behind, and whether these effects are linked to cell engraftment and not to their secreted products is not fully known.

Purpose

The aim of this study was to investigate the electrophysiological modifications induced by extracellular vesicles secreted by human cardiosphere-derived cells (CDC-EVs) in an in vitro model of atrial fibrillation in order to explore their potential antiarrhythmic effect.

Methods

CDCs were derived from cardiac biopsies of patients who underwent cardiac surgery for other reasons. Purified CDC-EVs resuspended in serum-free media (SFM) vs. SFM alone were added to HL-1 atrial myocyte monolayers presenting spontaneous fibrillatory activity. After 48 hours, the monolayers were fully confluent, and the electrophysiological properties were analysed through optical mapping in both the treated (n=9) and control plates (n=9). Optical mapping recordings of the monolayers were analysed with Matlab for the activation frequency, activation complexity, rotor dynamics (curvature and meandering) and conduction velocity.

Results

CDC-EVs reduced activation complexity of the fibrillating atrial monolayers by ∼40% (2.74±0.59 vs. 1.61±0.16 PS/cm2, p&lt;0.01). This reduction in activation complexity was accompanied by larger rotor meandering (1.47±0.82 vs. 4.32±2.25 cm/s, p&lt;0.01) and decreased curvature (1.79±0.40 vs. 0.87±0.24 rad/cm, p&lt;0.01) in the treated group. Despite reduction in the activation complexity, activation frequency did not change significantly between both groups. This could be in part because CDC-EVs increased conduction velocity by 80% (1.32±0.57 vs. 2.65±0.87 cm/s, p&lt;0.01). Low conduction velocity has been linked to higher reentry recurrence, and lower meandering and higher curvature to higher rotor stability and harder AF termination. Therefore, CDC-EVs seem to drive cardiomyocytes to a less arrhythmic profile reducing activation complexity and preventing remodelling by increasing conduction velocity and modifying rotor dynamics.

Conclusions

CDC-EVs significantly modify conduction velocity and rotor dynamics, therefore reducing fibrillation complexity and remodelling to drive atrial myocytes to a less arrhythmogenic profile. Testing CDC-EVs in more robust models of atrial fibrillation, the most common sustained arrhythmia in humans with significant morbidity and mortality, is of special interest.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III, Ministerio de Ciencia e Innovaciόn,CIBERCV, Spain Figure 1

Runs of homozygosity provide a genome landscape picture of inbreeding and genetic history of European autochthonous and commercial pig breeds

ROHs are long stretches of DNA homozygous at each polymorphic position. The proportion of genome covered by ROHs and their length are indicators of the level and origin of inbreeding. Frequent common ROHs within the same population define ROH islands and indicate hotspots of selection. In this work, we investigated ROHs in a total of 1131 pigs from 20 European local pig breeds and in three cosmopolitan breeds, genotyped with the GGP Porcine HD Genomic Profiler. plink software was used to identify ROHs. Size classes and genomic inbreeding parameters were evaluated. ROH islands were defined by evaluating different thresholds of homozygous SNP frequency. A functional overview of breed-specific ROH islands was obtained via over-representation analyses of GO biological processes. Mora Romagnola and Turopolje breeds had the largest proportions of genome covered with ROH (~1003 and ~955 Mb respectively), whereas Nero Siciliano and Sarda breeds had the lowest proportions (~207 and 247 Mb respectively). The highest proportion of long ROH (>16 Mb) was in Apulo-Calabrese, Mora Romagnola and Casertana. The largest number of ROH islands was identified in the Italian Landrace (n = 32), Cinta Senese (n = 26) and Lithuanian White Old Type (n = 22) breeds. Several ROH islands were in regions encompassing genes known to affect morphological traits. Comparative ROH structure analysis among breeds indicated the similar genetic structure of local breeds across Europe. This study contributed to understanding of the genetic history of the investigated pig breeds and provided information to manage these pig genetic resources.

Genome-wide detection of copy number variants in European autochthonous and commercial pig breeds by whole-genome sequencing of DNA pools identified breed-characterising copy number states

In this study, we identified copy number variants (CNVs) in 19 European autochthonous pig breeds and in two commercial breeds (Italian Large White and Italian Duroc) that represent important genetic resources for this species. The genome of 725 pigs was sequenced using a breed-specific DNA pooling approach (30-35 animals per pool) obtaining an average depth per pool of 42×. This approach maximised CNV discovery as well as the related copy number states characterising, on average, the analysed breeds. By mining more than 17.5 billion reads, we identified a total of 9592 CNVs (~683 CNVs per breed) and 3710 CNV regions (CNVRs; 1.15% of the reference pig genome), with an average of 77 CNVRs per breed that were considered as private. A few CNVRs were analysed in more detail, together with other information derived from sequencing data. For example, the CNVR encompassing the KIT gene was associated with coat colour phenotypes in the analysed breeds, confirming the role of the multiple copies in determining breed-specific coat colours. The CNVR covering the MSRB3 gene was associated with ear size in most breeds. The CNVRs affecting the ELOVL6 and ZNF622 genes were private features observed in the Lithuanian Indigenous Wattle and in the Turopolje pig breeds respectively. Overall, the genome variability unravelled here can explain part of the genetic diversity among breeds and might contribute to explain their origin, history and adaptation to a variety of production systems.

Abstract C103: ERRβ: Validating a novel target for triple-negative breast cancer

Triple-negative breast cancer (TNBC)—defined as estrogen receptor- (ER), progesterone receptor- (PR), and human epidermal growth factor receptor 2- (HER2) negative—is a highly aggressive form of breast cancer prevalent in African-American (AA) women. Current treatment strategies rely on cytotoxic chemotherapy because ER- and HER2-targeted therapies are ineffective in TNBC, leaving a tremendous need for new effective therapies with less toxicity. Nuclear receptors are highly druggable targets. Classical examples include ligand-regulated receptors like ER, but there is opportunity for orphan nuclear receptors (ONR) to be studied as potential targets for cancer therapy. Our lab has published that increased mRNA expression of ONR estrogen-related receptor beta (ERRβ, gene symbol ESRRB) correlates with better recurrence- and distant metastasis-free survival in women with TNBC/basal-like breast cancer. We also showed that treatment with a small-molecule agonist ligand for ERRβ (DY131) has growth-inhibitory and antimitotic activity in TNBC cell lines. The goal of our current work is to comprehensively characterize ERRβ copy number, mRNA, protein expression, and ERRβ function in TNBC. ESRRB copy number was determined in 106 primary breast tumors (TNBC n=56, nonTNBC n=50) by Agilent SurePrint G3 Human CGH Microarray in a cohort AA and Caucasian (CA) women. ESRRB mRNA expression was determined in The Cancer Genome Atlas (TCGA) Breast Cancer RNAseq data. Association of ESRRB mRNA with overall survival was determined in Illumina gene expression array data from METABRIC. ERR protein expression is being assessed by immunohistochemistry (IHC) in a tissue microarray of 150 primary breast tumors (50 TNBC, 50 ER+, 50 HER2+). Ongoing studies are focusing on genetic modification of cell lines, specifically the overexpression of ERRβ in nontransformed mammary epithelial and TNBC cell lines.

DNA: In both TNBC and nonTNBC, AA patients had a markedly higher frequency of ESRRB copy number loss than CA patients (2 *p=0.012 for TNBC, p=0.052 for nonTNBC).

RNA: In TCGA breast cancer patients by PAM50 subtype, TNBC/basal-like patients have significantly lower ESRRB mRNA expression than Luminal A patients (*p=0.0015). Among systemically untreated patients in the METABRIC dataset, low ESRRB mRNA is significantly associated with poor overall survival in TNBC (hazard ratio 0.24, 95% confidence interval 0.07-0.85, *p=0.016).

Protein: Analysis of ERR protein expression by IHC is ongoing.

Function: Focusing on overexpression of ERRβ in cell lines, we aim to analyze multiple phenotypes including cell proliferation, cell invasion and migration, and differential gene expression.

Conclusions: Breast tumors from AA women are significantly more likely to have reduced ESRRB copy number vs. CA women. TNBC patients have lower ESRRB mRNA expression and low ESRRB mRNA expression predicts for poor overall survival in TNBC. These data suggest that ERRβ expression has prognostic value in breast cancer, particularly in TNBC.

Citation Format: Aileen I. Fernandez, Garrett Graham, Bálazs Györffy, Luciane R. Cavalli, Rebecca B. Riggins. ERRβ: Validating a novel target for triple-negative breast cancer [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C103.

The orphan nuclear receptor estrogen-related receptor beta (ERRβ) in triple-negative breast cancer

PURPOSE

Triple-negative breast cancer (TNBC)/basal-like breast cancer (BLBC) is a highly aggressive form of breast cancer. We previously reported that a small molecule agonist ligand for the orphan nuclear receptor estrogen-related receptor beta (ERRβ or ESRRB) has growth inhibitory and anti-mitotic activity in TNBC cell lines. In this study, we evaluate the association of ESRRB mRNA, copy number levels, and protein expression with demographic, clinicopathological, and gene expression features in breast tumor clinical specimens.

METHODS

ESRRB mRNA-level expression and clinical associations were analyzed using RNAseq data. Array-based comparative genomic hybridization determined ESRRB copy number in African-American and Caucasian women. Transcription factor activity was measured using promoter-reporter luciferase assays in TNBC cell lines. Semi-automatic quantification of immunohistochemistry measured ERRβ protein expression on a 150-patient tissue microarray series.

RESULTS

ESRRB mRNA expression is significantly lower in TNBC/BLBC versus other breast cancer subtypes. There is no evidence of ESRRB copy number loss. ESRRB mRNA expression is correlated with the expression of genes associated with neuroactive ligand-receptor interaction, metabolic pathways, and deafness. These genes contain G/C-rich transcription factor binding motifs. The ESRRB message is alternatively spliced into three isoforms, which we show have different transcription factor activity in basal-like versus other TNBC cell lines. We further show that the ERRβ2 and ERRβsf isoforms are broadly expressed in breast tumors at the protein level.

CONCLUSIONS

Decreased ESRRB mRNA expression and distinct patterns of ERRβ isoform subcellular localization and transcription factor activity are key features in TNBC/BLBC.

Homeoprotein DLX4 expression is increased in inflammatory breast cancer cases from an urban African-American population

Protein expression of Distal-less homeobox 4 (DLX4) was analyzed in inflammatory breast cancer (IBC) cases from an African-American (AA) population to determine if a) DLX4 gene over expression exists in this cohort and b) if the overexpression is associated with breast cancer clinicopathological characteristics (ER, PR, HER2, triple-negative). Twenty-nine blocks of formalin-fixed paraffin-embedded (FFPE) tissue from well-characterized human IBC cases were used for immunohistochemical staining (IHC). IHC results were assigned an intensity and percentage score. Percentage scores were assigned as 0, 1, 2, 3, or 4 and intensity scores were assigned 0, 1+, 2+ or 3+. For the analysis of the IHC, a percentage score of 3 or 4 and an intensity score of 2+ or 3+ were categorized as high. Chi-square or Fisher's exact tests were used to compare the high and low groups. In this cohort, 89.7% (26 out of 29) of IBC cases showed high percentages of positive cells staining for the DLX4 protein, while 40.0% (12 out of 30) of normal breast tissue from reduction mammoplasty cases demonstrated DLX4 expression (p < 0.01). In IBC patients, 65.5% of cases showed a high level of staining intensity, compared to 20.0% of normal breast tissues (test, p = 0.001). Intensity to DLX4 was higher in the HER2 negative status (78.3%) than the HER2 positive status (16.7%) (test, p = 0.011). DLX4 expression is higher in the IBC cases in this study of an urban AA population than in normal breast tissue cases. HER2 negative status is positively associated with high intensity of DLX4.

Antimitotic activity of DY131 and the estrogen-related receptor beta 2 (ERRβ2) splice variant in breast cancer

Breast cancer remains a leading cause of cancer-related death in women, and triple negative breast cancer (TNBC) lacks clinically actionable therapeutic targets. Death in mitosis is a tumor suppressive mechanism that occurs in cancer cells experiencing a defective M phase. The orphan estrogen-related receptor beta (ERRβ) is a key reprogramming factor in murine embryonic and induced pluripotent stem cells. In primates, ERRβ is alternatively spliced to produce several receptor isoforms. In cellular models of glioblastoma, short form (ERRβsf) and beta2 (ERRβ2) splice variants differentially regulate cell cycle progression in response to the synthetic agonist DY131, with ERRβ2 driving arrest in G2/M.The goals of the present study are to determine the cellular function(s) of ligand-activated ERRβ splice variants in breast cancer and evaluate the potential of DY131 to serve as an antimitotic agent, particularly in TNBC. DY131 inhibits growth in a diverse panel of breast cancer cell lines, causing cell death that involves the p38 stress kinase pathway and a bimodal cell cycle arrest. ERRβ2 facilitates the block in G2/M, and DY131 delays progression from prophase to anaphase. Finally, ERRβ2 localizes to centrosomes and DY131 causes mitotic spindle defects. Targeting ERRβ2 may therefore be a promising therapeutic strategy in breast cancer.

Abstract P3-07-09: ERRβ copy number and expression in triple negative breast cancer

Introduction: Triple negative breast cancer (TNBC) is a highly aggressive form of breast cancer prevalent in African-American (AA) women defined as estrogen receptor- (ER), progesterone receptor- (PR), and human epidermal growth factor receptor 2- (HER2) negative. Because ER- and HER2-targeted therapies are ineffective in TNBC, systemic chemotherapy is the standard of care and there is a tremendous need for new effective therapies with less toxicity. Steroid hormone receptors are highly druggable targets, and orphan nuclear receptors, members of the nuclear receptor superfamily, are emerging as targets for cancer therapy. In fact, we have previously shown that treatment of TNBC cells with a small molecule agonist ligand (DY131) for estrogen related receptor beta (ERRβ), has growth inhibitory and anti-mitotic activity. We have also shown that increased mRNA expression of ERRβ, correlates with better recurrence- and distant metastasis-free survival in TNBC/basal-like breast cancer. The goal of our current work is to comprehensively characterize ERRβ copy number and mRNA status in TNBC and determine its association with patients' prognosis.

Methods: ESRRB copy number was determined in 106 primary breast tumors (TNBC n=56, nonTNBC n=50) by array-CGH, using the Agilent SurePrint G3 Human CGH platform. ESRRB mRNA data and its association with overall survival was determined in systemically untreated patients from METABRIC using Illumina gene expression array data (probe ID ILMN_1707398).

Results: Copy number alterations (CNAs). Copy number losses at the ESRRB locus (14q24.3) were observed in 10/56 (17.8%) of TNBC vs. 10/50 (20%) of nonTNBC, while copy number gains were detected in 43/56 (76.8%) of TNBC vs. 29/50 (58%) of nonTNBC (c2 *p=0.036). Interestingly, in both TNBC and non-TNBC, ESRRB loss was seen with markedly higher frequency in AA patients when compared to Caucasian (CA) patients (c2 *p=0.012 for TNBC, p=0.052 for non-TNBC). mRNA expression. Among patients not treated with systemic chemotherapy in the METABRIC dataset, low ESRRB mRNA was significantly associated with shorter overall survival in TNBC, but not ER+ or HER2+ patients (TNBC hazard ratio 0.24, 95% confidence interval 0.07-0.85, *p=0.016). Low ESRRB also correlated with reduced overall survival in TP53 mutant (but not wild type) tumors (hazard ratio 0.28, 95% confidence interval 0.1-0.82, *p=0.013).

Conclusions: ESRRB presents significantly high levels of copy number losses in TNBC when compared to non-TNBC tumors. In breast tumors from AA women, both the TNBC and non-TNBC subtypes are significantly more likely to have reduced ESRRB copy number vs. CA women. Low ESRRB mRNA expression predicts for poor overall survival in TNBC and TP53 mutant tumors. These data advocate that ERRβ expression has prognostic value in breast cancer, particularly TNBC. Future goals include immunohistochemistry staining, and analysis, of a tissue microarray consisting of 150 primary breast tumors (50 TNBC, 50 ER+, 50 HER2+); as well as ERRβ overexpression and knock-down studies in TNBC cell lines to define the role it plays in TNBC.

Citation Format: Fernandez AI, Graham G, Győrffy B, Cavalli L, Mahajan A, Riggins RB. ERRβ copy number and expression in triple negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-07-09.

Differential prioritization of therapies to subtypes of triple negative breast cancer using a systems medicine method

Triple negative breast cancer (TNBC) is a group of cancers whose heterogeneity and shortage of effective drug therapies has prompted efforts to divide these cancers into molecular subtypes. Our computational platform, entitled GenEx-TNBC, applies concepts in systems biology and polypharmacology to prioritize thousands of approved and experimental drugs for therapeutic potential against each molecular subtype of TNBC. Using patient-based and cell line-based gene expression data, we constructed networks to describe the biological perturbation associated with each TNBC subtype at multiple levels of biological action. These networks were analyzed for statistical coincidence with drug action networks stemming from known drug-protein targets, while accounting for the direction of disease modulation for coinciding entities. GenEx-TNBC successfully designated drugs, and drug classes, that were previously shown to be broadly effective or subtype-specific against TNBC, as well as novel agents. We further performed biological validation of the platform by testing the relative sensitivities of three cell lines, representing three distinct TNBC subtypes, to several small molecules according to the degree of predicted biological coincidence with each subtype. GenEx-TNBC is the first computational platform to associate drugs to diseases based on inverse relationships with multi-scale disease mechanisms mapped from global gene expression of a disease. This method may be useful for directing current efforts in preclinical drug development surrounding TNBC, and may offer insights into the targetable mechanisms of each TNBC subtype.

The mushroom body D1 dopamine receptor controls innate courtship drive

Mating is critical for species survival and is profoundly regulated by neuromodulators and neurohormones to accommodate internal states and external factors. To identify the underlying neuromodulatory mechanisms, we investigated the roles of dopamine receptors in various aspects of courtship behavior in Drosophila. Here, we report that the D1 dopamine receptor dDA1 regulates courtship drive in naïve males. The wild‐type naïve males actively courted females regardless their appearance or mating status. On the contrary, the dDA1 mutant (dumb) males exhibited substantially reduced courtship toward less appealing females including decapitated, leg‐less and mated females. The dumb male's reduced courtship activity was due to delay in courtship initiation and prolonged intervals between courtship bouts. The dampened courtship drive of dumb males was rescued by reinstated dDA1 expression in the mushroom body α/β and γ neurons but not α/β or γ neurons alone, which is distinct from the previously characterized dDA1 functions in experience‐dependent courtship or other learning and memory processes. We also found that the dopamine receptors dDA1, DAMB and dD2R are dispensable for associative memory formation and short‐term memory of conditioned courtship, thus courtship motivation and associative courtship learning and memory are regulated by distinct neuromodulatory mechanisms. Taken together, our study narrows the gap in the knowledge of the mechanism that dopamine regulates male courtship behavior.

Abstract 4131: ERRβ: Validating a novel target for triple negative breast cancer

Triple negative breast cancer (TNBC) - defined as estrogen receptor- (ER), progesterone receptor- (PR), and human epidermal growth factor receptor 2- (HER2) negative - is a highly aggressive form of breast cancer prevalent in African-American (AA) women. Because ER- and HER2-targeted therapies are ineffective in TNBC, current treatment strategies rely on cytotoxic chemotherapy. There is a tremendous need for new approaches that can identify effective therapies with less toxicity for this devastating form of breast cancer.

Nuclear receptors are highly druggable targets. Classical examples include ligand-regulated receptors like ER, but orphan nuclear receptors are also emerging as targets for cancer therapy. We recently published that increased mRNA expression of estrogen-related receptor beta (ERRβ, gene symbol ESRRB) correlates with better recurrence- and distant metastasis-free survival in women with TNBC, and that a small molecule agonist ligand for ERRβ (DY131, DY) has growth inhibitory and anti-mitotic activity in TNBC cell lines of multiple molecular subtypes. The goal of our current work is to validate ERRβ as a novel therapeutic target for TNBC in two distinct ways.

First, we sought to determine whether ERRβ is correlated with survival outcome specifically in African-American (AA) women. Analysis of The Cancer Genome Atlas (TCGA) Breast Cancer RNAseq data shows that low ERRβ mRNA expression is specifically associated with poor overall survival in AA women with TNBC. This association is not observed in AA women with ER- or HER2-positive disease. We further find that while ERRβ mRNA expression is decreased in tumor vs. normal breast tissue regardless of race, this decrease is more pronounced in AA women. Ongoing studies in an independent cohort of AA and white women will determine whether this is due, in part, to copy number changes at the ERRβ locus (chromosome 14q24.3).

Second, we sought to determine whether ERRβ expression could predict response to current treatment strategies commonly used in breast cancer, particularly TNBC. Using multiple combined datasets, we find that high ERRβ expression is associated with improved recurrence-free survival (RFS) in women with TNBC who received adjuvant or neoadjuvant therapy with anthracycline (e.g. doxorubicin, Adriamycin). No association between ERRβ and RFS is observed in patients treated with taxanes. Ongoing studies in TNBC cell lines seek to determine if activating ERRβ with its agonist ligand DY can enhance doxorubicin-mediated growth inhibition and cell death.

Citation Format: Aileen I. Fernandez, Garrett Graham, Balázs Győrffy, Luciane Cavalli, Rebecca B. Riggins. ERRβ: Validating a novel target for triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4131. doi:10.1158/1538-7445.AM2017-4131

A large-scale, rapid public health response to rabies in an organ recipient and the previously undiagnosed organ donor

This article describes and contrasts the public health response to two human rabies cases: one organ recipient diagnosed within days of symptom onset and the transplant donor who was diagnosed 18 months post-symptom onset. In response to an organ-transplant-related rabies case diagnosed in 2013, organ donor and recipient investigations were conducted by multiple public health agencies. Persons with potential exposure to infectious patient materials were assessed for rabies virus exposure. An exposure investigation was conducted to determine the source of the organ donor's infection. Over 100 persons from more than 20 agencies spent over 2700 h conducting contact investigations in healthcare, military and community settings. The 564 persons assessed include 417 healthcare workers [5.8% recommended for post-exposure prophylaxis (PEP)], 96 community contacts (15.6% recommended for PEP), 30 autopsy personnel (50% recommended for PEP), and 21 other persons (4.8% recommended for PEP). Donor contacts represented 188 assessed with 20.2% recommended for PEP, compared with 5.6% of 306 recipient contacts recommended for PEP. Human rabies cases result in substantial use of public health and medical resources, especially when diagnosis is delayed. Although rare, clinicians should consider rabies in cases of encephalitis of unexplained aetiology, particularly for cases that may result in organ donation.

Ion chemistry of NOO+

The kinetics for the reactions of NOO+ ions with neutral molecules having ionization potentials (IPs) from 9.27 to 15.58 eV was measured in a selected ion flow tube at 298 K. The NOO+ ions are produced from the reaction of N3+ + O2 and have been reacted with the following: NO, C6F6, CS2, CF3I, C3F6, OCS, C2H6, Xe, SO2, O3, N2O, CO2, Kr, CO, D2, and N2. Numerous types of reactions were observed with the various neutral reagents, including production of NO+ (which may involve loss of an O from the ion or addition of O to the neutral reactant, although the two channels could not be distinguished here), charge transfer, isomerization of NOO+ to ONO+, and hydride abstraction. High level theoretical calculations of the structures and energetics of the various isomers, electronic states, and transition states of NOO and NOO+ were performed to better understand the observed reactivity. All neutral species with an IP< or =11.18 eV were observed to react with NOO+ in part by charge transfer. Detailed calculations showed that the recommended adiabatic and vertical IPs of NOO are 10.4 and 11.7 eV, respectively, at the MRCISDQ/AVQZ level of theory. The observed experimental limit for charge transfer of 11.18 eV agreed well with the energetics of the final products obtained from theory if dissociation of the neutral metastable product occurred, i.e., the products were X+ +[O(3P) + NO(2Pi)], where [O(3P)+NO(2Pi)] formed via dissociation of metastable NOO. Charge exchange with neutral reagent X would, therefore, be exothermic if IP(X)<[IPad(NOO)-DeltaE(O+NO)-NOO]= approximately 11.1 eV, where IPad(NOO) is the adiabatic IP. The potential energy surface for the reaction of NOO+ with C2H6 was also calculated, indicating that two pathways for formation of HNO2 + C2H5 (+) exist.

Change of mechanical properties during short-term natural weathering of MSWI bottom ash

The present work describes the change of mechanical properties during the natural weathering of freshly quenched processed bottom ash. An unconfined uniaxial compression to failure test of the unbound material was used to determine compressive strength and modulus of elasticity. Three main stages of mechanical behavior were determined. In the first stage, during a period lower than 30 days, mechanical properties suddenly increase, with a compressive strength and elastic modulus 7 times greater than the initial parameters. During the second stage, compressive strength and modulus of elasticity lightly increase until approximately 90 days of curing time. Starting from this period both mechanical properties remain steady and independent of the curing time. The neoformed phases, the elevated water content, and the improvement of particle contact after compaction act as a binder layer among particles, increasing the mechanical parameters during the short-term natural weathering process. Because of this, the freshly compacted bottom ash progresses from behaving as an unbound material into a bound pavement material. These mechanical properties obtained from freshly quenched bottom ash are 6-7 times greater than those obtained from previously weathered bottom ash. The bottom ash expansion and leaching of metals were also evaluated.

Siderophore production by Aeromonas salmonicida subsp. salmonicida. Lack of strain specificity

Siderophore production, presence of iron-regulated outer membrane proteins and siderophore specificity was determined among 17 isolates of Aeromonas salmonicida subsp. salmonicida obtained from Spain and Scotland. All grew in the presence of ethylenediamine di(o-hydroxyphenylacetic acid) (EDDA) and siderophore production was detected using chrome azurol S (CAS) agar, confirming the presence of a high-affinity siderophore iron-uptake mechanism. The Arnow test confirmed that all isolates produced a catechol siderophore. Cross-feeding assays with indicator bacteria showed the absence of anguibactin, enterobactin, 2,3-dihydroxybenzoic acid (DHBA) and the hydroxamate siderophore, aerobactin, in the iron-restricted supernants of a representative isolate which cross fed 15/17 A. salmonicida isolates tested. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) showed the presence of the same 2 major iron-regulated outer membrane proteins (IROMPs) in all isolates when grown in iron-restricted conditions and siderophore strain specificity as assessed by cross-feeding experiments was not apparent. Thus, with respect to IROMP and siderophore production A. salmonicida appears to be a homogeneous species.

Effects of phorbol 12,13-dibutyrate and H-7 in extravascular smooth muscle contraction

The effect of the activator, phorbol 12,13-dibutyrate (PDB), and the inhibitor, H-7, of protein kinase C (PKC) has been assayed in rat uterus. PDB increases the amplitude of spontaneous contractions of rat uterus and this effect does not occur in the presence of H-7 or nifedipine. PDB did not modify the KCl-induced tonic contraction but H-7 relaxed it, in a concentration-dependent way. PDB inhibited the contraction induced by oxytocin in rat uterus incubated in Ca-free solution and relaxed the tonic contraction induced by oxytocin in this medium. The relaxing effect of PDB on oxytocin-induced contraction was not modified by H-7. Thus H-7 relaxed, in a concentration-dependent way, the tonic contractions induced by oxytocin and vanadate in the rat uterus incubated in Ca-free medium. Our results suggest a dual effect of PDB related to calcium, and a direct and PKC-independent inhibitory effect of H-7.

Differential effect of calcium and Bay K 8644 on the inhibitory action of estrogens in the rat uterus

1. The effects of the estrogens estradiol (E2, 10(-7) to 3 x 10(-5) M) and diethylstilbestrol (DES, 10(-7) to 3 x 10(-6) M) on tonic contractions of the rat uterus induced by KCl and CaCl2 have been studied. 2. E2 and DES relaxed, in a dose-dependent way, the tonic contraction induced by KCl (60 mM) (IC50: 5.16 +/- 1.49 x 10(-6) and 4.51 +/- 0.03 x 10(-7) M); the tonic contraction induced by CaCl2 (3 mM) in the rat uterus incubated in depolarizing Krebs (127 mM of K+) have also been relaxed (IC50: 8.6 +/- 0.03 x 10(-7) and 2.56 +/- 0.07 x 10 M) by both drugs. 3. The CaCl2 (0.1 to 10 mM) counteracted the relaxing effect of E2 and DES, respectively, up to 28.13 +/- 10.2% and 34.71 +/- 11.5%, on KCl-induced contractions, and up to 126.36 +/- 19.35% and 95.8 +/- 16.3% on CaCl2-induced contractions. 4. Bay K 8644 (10(-10) to 10(-6) M) reversed the relaxing effect of E2 and DES, respectively, up to 42.49 +/- 2.28% and 43.31 +/- 3.59% on KCl-induced contractions, and up to 21.73 +/- 4.16% and 75.97 +/- 9.63% on CaCl2-induced contractions. 5. Propranolol (10(-6) M) did not modify the relaxing effect of E2 or DES on CaCl2-induced contractions.

Mediators involved in the rat uterus contraction in calcium-free solution

1. The effect of (Na+ + K+)-ATPase inhibitor ouabain (10(-5)-3 x 10(-4) M), and the (Ca2+ + Mg2+)-ATPase inhibitors vanadate (6 x 10(-6)-6 x 10(-4) M), oxytocin (2 x 10(-9)-4 x 10(-8) M, and prostaglandin F2 alpha (PGF2 alpha, 10(-7)-6 x 10(-6) M) were assayed on rat uterus incubated in Ca-free medium. 2. Vanadate, oxytocin and PGF2 alpha, but not ouabain, induced contractions in a dose-dependent way (ED50: 7.5 +/- 0.03 x 10(-5) M; 6.5 +/- 0.064 x 10(-9) M and 3.8 +/- 0.085 x 10(-7) M). 3. Vanadate (3 x 10(-4) M) and oxytocin (OT, 10 mU/ml = 2 x 10(-8) M)-induced tonic contraction were not modified by nifedipine (10(-10)-10(-6) M), monensin (10(-5)-3 x 10(-4) M) or amiloride (10(-5)-10(-3) M). 4. The intracellular calcium release inhibitors TMB-8 (10(-6)-10(-4) M) and dantrolene (3 x 10(-6)-10(-4) M), and the prostaglandin release inhibitor indomethacin (3 x 10(-8)-6 x 10(-5) M) relaxed the vanadate and OT-induced tonic contractions. 5. The calmodulin inhibitors trifluoperazine (3 x 10(-5)-3 x 10(-4) M), bepridil (10(-8)-3 x 10(-4) M), calmidazolium (10(-7)-10(-4) M) and W-7 (10(-7)-10(-5) M) also relaxed the vanadate and OT-induced tonic contractions. 6. Our results suggest that oxytocin and vanadate-induced contractions on rat uterus in Ca-free medium could be produced by release of prostaglandins and intracellular calcium, and mediated by calmodulin.