Identifying prognostic biomarkers for palbociclib add-on therapy in fulvestrant-resistant breast cancer using cell-free DNA sequencing

BACKGROUND

The FUTURE trial (UMIN000029294) demonstrated the safety and efficacy of adding palbociclib after fulvestrant resistance in patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) advanced and metastatic breast cancer (ABC/MBC). In this planned sub-study, cancer panel sequencing of cell-free DNA (cfDNA) was utilized to explore prognostic and predictive biomarkers for further palbociclib treatment following fulvestrant resistance.

MATERIALS AND METHODS

Herein, 149 cfDNA samples from 65 patients with fulvestrant-resistant disease were analysed at the time of palbociclib addition after fulvestrant resistance (baseline), on day 15 of cycle 1, and at the end of treatment using the assay for identifying diverse mutations in 34 cancer-related genes.

RESULTS

During the course of treatment, mutations in ESR1, PIK3CA, FOXA1, RUNX1, TBX3, and TP53 were the most common genomic alterations observed. Analysis of genomic mutations revealed that before fulvestrant introduction, baseline PIK3CA mutations were marginally lower in metastatic aromatase inhibitor (AI)-treated patients compared to adjuvant AI-treated patients (P = 0.063). Baseline PIK3CA mutations were associated with poorer progression-free survival [hazard ratio: 1.62, P = 0.04]. Comparative analysis between baseline and early-changing gene mutations identified poor prognostic factors including early-changing MAP3K1 mutations (hazard ratio: 4.66, P = 0.04), baseline AR mutations (hazard ratio: 3.53, P = 0.04), and baseline PIK3CA mutations (hazard ratio: 3.41, P = 0.02). Notably, the relationship between ESR1 mutations and mutations in PIK3CA, MAP3K1, and TP53 weakened as treatment progressed. Instead, PIK3CA mutations became correlated with TP53 and FOXA1 mutations.

CONCLUSIONS

Cancer panel testing for cfDNA identified prognostic and predictive biomarkers for palbociclib add-on therapy after acquiring fulvestrant resistance in patients with HR+/HER2- ABC/MBC.

Improved Measurements of Muonic Helium Ground-State Hyperfine Structure at a Near-Zero Magnetic Field

Muonic helium atom hyperfine structure (HFS) measurements are a sensitive tool to test the three-body atomic system and bound-state quantum electrodynamics theory, and determine fundamental constants of the negative muon magnetic moment and mass. The world's most intense pulsed negative muon beam at the Muon Science Facility of the Japan Proton Accelerator Research Complex allows improvement of previous measurements and testing further CPT invariance by comparing the magnetic moments and masses of positive and negative muons (second-generation leptons). We report new ground-state HFS measurements of muonic helium-4 atoms at a near-zero magnetic field, performed for the first time using a small admixture of CH_{4} as an electron donor to form neutral muonic helium atoms efficiently. Our analysis gives Δν=4464.980(20)  MHz (4.5 ppm), which is more precise than both previous measurements at weak and high fields. The muonium ground-state HFS was also measured under the same conditions to investigate the isotopic effect on the frequency shift due to the gas density dependence in He with CH_{4} admixture and compared with previous studies. Muonium and muonic helium can be regarded as light and heavy hydrogen isotopes with an isotopic mass ratio of 36. No isotopic effect was observed within the current experimental precision.

Achilles tendon thickness assessed by X-ray predicting a pathogenic mutation in familial hypercholesterolemia gene

Background

The 2017 Japan Atherosclerosis Society (JAS) familial hypercholesterolemia (FH) criteria adopts a cut off value of ≥9 mm of Achilles tendon thickness (ATT) detected by X-ray as one of the three key items. This threshold was determined based on an old data assessing ATT of 36 non-FH individuals published in 1977. Although the specificity of this clinical criteria is extremely high due to a strict threshold, there are substantial number of patients with FH whose ATT <9 mm. We aimed to determine a cut off value of ATT detected by X-ray to differentiate FH and non-FH based on genetic diagnosis.

Methods

The individuals (male/female = 486/501) with full assessments of genetic analyses for FH-genes (LDLR, and PCSK9), serum lipids, and ATT detected by X-ray at Kanazawa University Hospital and National Cerebral and Cardiovascular Center Research Institute were included in this study. Receiver operating characteristic (ROC) analyses were performed to determine a better cut off point of ATT predicting a pathogenic mutation of FH.

Results

ROC analyses revealed the best cut off values of ATT as 7.6 mm for male, and 7.0 mm for female with the sensitivities and specificities of 0.83 and 0.83 for male and 0.86 and 0.85 for female, respectively. If the thresholds of ATT of 8.0/7.5 mm and 7.5/7.0 mm were applied to diagnose of male/female FH, the sensitivities/specificities predicting a pathogenic mutation of FH by the 2017 JAS FH clinical criteria would be 0.82/0.90 and 0.85/0.88, respectively.

Conclusions

These results suggest that the cut-off value of ATT detected by X-ray is obviously lower than 9.0 mm adopted by the 2017 JAS FH clinical criteria.

Funding Acknowledgement

Type of funding sources: None.

Direct comparison of bioabsorbable and biodurable polymer everolimus-eluting stent in neointimal stent coverage and in-stent thrombus using high-resolution angioscope

Background/Introduction

Although second-generation drug eluting stent (DES) employing biodurable polymer drastically shortened the duration of dual antiplatelet therapy (DAPT), previous reports raised concerns that switching from DAPT to single antiplatelet therapy increased rates of subsequent stent thrombosis with time. Third-generation DES employing bioabsorbable polymer has been introduced so as not to hinder the healing process of the vessel wall, however, at present, both DES with bioabsorbable polymer and those with biodurable polymer are used in parallel. It means there is no conclusive evidence regarding pros and cons of these two types of polymers.

Purpose

This study aims to clarify how bioabsorbable polymer and biodurable polymer act on the human coronary artery by observing neointimal stent coverage (NIC) and in-stent thrombus by comparing the third-generation DES with bioabsorbable-polymer cobalt-platinum everolimus-eluting stent (BP CoPt-EES), and the second-generation DES with biodurable-polymer cobalt-chromium everolimus-eluting stent (DP CoCr-EES).

Methods

This is a multicenter observational study including 11 hospitals. We investigated 70 stents (BP CoPt-EES: 40, DP CoCr-EES: 30) of 60 cases, who underwent stent implantation followed by simultaneous observation by coronary angiography, IVUS and angioscopy within 6 to 12 months. For angioscopy, we used a recently available, high-resolution angioscope with a pixel count of 9,000 which realized both stent coverage analysis and planar thrombus detection precisely. Neointimal stent coverage was graded from G0: non coverage to G3: full coverage, and heterogeneity value of neointima was measured as the difference between maximum and minimum NIC grade.

Results

A strong relationship was observed between NIC grade and in-stent thrombus in all stents (p=0.0011), and between the heterogeneity value and stent thrombus (p=0.012). There was no statistical difference in NIC grade between BP CoPt-EES vs. DP CoCr-EES; grade 0: 0 (0.0%) vs. 2 (6.7%), grade 1: 13 (32.5%) vs. 11 (36.7%), grade 2: 6 (15.0%) vs. 6 (20.0%), grade 3: 21 (52.5%) vs. 11 (36.7%), p=0.17) and neither in the heterogeneity value of neointima (p=0.49). The ratio of stent thrombus did not reach statistical difference; 16 (40.0%) in BP CoPt-EES vs. 17 (56.7%) in DP CoCr-EES (p=0.23).

Conclusion

The existence of stent thrombus was associated with the neointimal stent coverage. There was no significant difference both in neointimal stent coverage and stent thrombus between bioabsorbable polymer cobalt-platinum EES and biodurable polymer cobalt-chromium EES after 6 to 12 months following stent deployment.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Boston Scientific JapanOvalis ltd

Impact of cumulative exposure to LDL cholesterol on cardiovascular events in patients with familial hypercholesterolemia

Aims

Recent studies suggest that cumulative exposure to LDL-cholesterol (LDL-C) leads to the development of atherosclerotic cardiovascular disease (ASCVD). However, few studies have investigated whether this link extends to individuals with familial hypercholesterolemia (FH), a relevant patient population. We aimed to determine whether cholesterol-year-score, an indicator of cumulative exposure to LDL-C, is associated with ASCVD events among Japanese patients with FH

Methods and results

We retrospectively investigated the health records of 1,050 patients with clinical FH diagnosis who were referred to our institute between April 1990 and March 2019. We used Cox proportional hazards models adjusted for established ASCVD risk factors to assess the association between cholesterol-year-score and major adverse cardiovascular events (MACEs), including death from any cause or hospitalization due to ASCVD events. Cholesterol-year-score was calculated as LDL-C max × [age at diagnosis / statin initiation] + LDL-C at inclusion × [age at inclusion − age at diagnosis / statin initiation]. The median follow-up period for MACE evaluation was 12.3 (interquartile range, 9.1–17.5) years, and 177 patients experienced MACEs during the observation period. Cholesterol-year-score was significantly associated with MACEs (hazard ratio [HR], 1.35; 95% confidence interval, 1.07–1.53; P=0.0034, per 1,000 mg-year/dL), independent of other traditional risk factors including age and LDL-C, based on cross-sectional assessment. Cholesterol-year-score improved the discrimination ability of other traditional risk factors for ASCVD events (C-index, 0.901 versus 0.889; P=0.00473).

Conclusion

Cumulative LDL-C exposure was strongly associated with MACEs in Japanese patients with FH, warranting early diagnosis and treatment initiation in these patients.

Funding Acknowledgement

Type of funding sources: None.

Creation of mortality risk calculator using a I-123 mIBG-based machine learning model: differential prediction of arrhythmic death and heart-failure death

Funding Acknowledgements

Type of funding sources: None.

Background

Although I-123 meta-iodobenzylguanidine (mIBG) has been applied to patients with chronic heart failure (CHF), a diagnostic tool for differential prediction of fatal arrhythmic events (ArE) and heart-failure death (HFD) has been pursued. 

Purpose

The aim of this study was to create a calculator of mortality risk for differentiating mode of cardiac death using a machine learning (ML) method, and to test the accuracy in a new cohort of patients with CHF.

Methods

A total of 529 patients with CHF was used as the training database for ML. The ArE group consisted of patients with arrhythmic death, sudden cardiac death and appropriate therapy by implantable cardioverter defibrillator. A heart-to-mediastinum ratio (H/M) standardized to the medium-energy collimator condition was calculated with a planar anterior mIBG scintigram. The best classifier models for predicting HFD and ArE were determined by four-fold cross validation. Input variables included age, sex, New York Heart Association (NYHA) functional class, left ventricular ejection fraction, ischemic etiology, mIBG H/M and washout rate, and b-type natriuretic peptide (BNP) or NT Pro BNP, estimated glomerular filtration rate, hemoglobin, and complications such as diabetes and hypertension. After creating the ML-based model, the constructed classifier functions for ArE, HFD, and survival were exported for subsequent use. A new cohort of patients (n = 312, age 67 ± 13 years, 2015 or later) was used to test the ML-based model.

Results

The training database included 141 events (27%) with ArE (7%) and HFD (20%). Receiver-operating characteristic analysis by four-fold validation showed area under the curve value of 0.90 for HFD and 0.73 for ArE. Among various ML methods, the logistic regression method demonstrated the most stable calculation of the probability of ArE followed by random forest and gradient boosted tree methods. Therefore, the logistic-regression method was used for calculating both HFD and ArE probabilities. In the test cohort, patients with a high HFD probability >8% resulted in 6.3-fold higher HFD than those with low probability (≤ 8%). Patients with high ArE probability >8% showed 2.5-fold higher ArE than those with low probability (≤ 8%).

Conclusion

The ML-based mortality risk calculator could be used for stratifying patients at high and low risks, which might be useful for estimating appropriate treatment strategy.

Prognostic impact of cascade screening for familial hypercholesterolemia on cardiovascular events

Background

Early diagnosis and timely treatment for the patients with familial hypercholesterolemia (FH) can substantially lower the risk of atherosclerotic cardiovascular disease (ASCVD). In this sense, cascade screening could be one of the most useful options. However, few data exist regarding the impact of cascade screening for FH on the reduction of risk of ASCVD events.

Objectives

We aimed to evaluate the prognostic impact of cascade screening for FH.

Methods

We retrospectively investigated the health records of 1,050 patients with clinically diagnosed FH, including probands and their relatives who were cascade-screened. We used Cox models that were adjusted for established ASCVD risk factors to assess the association between cascade screening and major adverse cardiovascular events (MACE). The median period of follow-up was 12.3 years (interquartile range [IQR] = 9.1–17.5 years), and MACE included death from any causes or hospitalization due to ASCVD events.

Results

During the observation period, 246 participants experienced MACE. The mean age of patients identified through cascade screening was 18-years younger than that of the probands (38.7 yr vs. 57.0 yr, P<0.001), with a lower proportion of ASCVD risk factors. Interestingly, patients identified through cascade screening under milder lipid-lowering therapies were at reduced risk for MACE (hazard ratio [HR] = 0.36; 95% CI = 0.22 to 0.60; P<0.001) when compared with the probands, even after adjusting for those known risk factors.

Conclusions

The identification of patients with FH via cascade screening appeared to result in better prognoses.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Scientific research grants from the Ministry of Education, Science and Culture of Japan (no. 16K19394, 18K08064, and 19K08575)

Recurrence of atrial fibrillation after catheter ablation is associated with major adverse cardiac and cerebrovascular events: insights from AF frontier ablation registry

Background

Recent observational studies have suggested that catheter ablation for atrial fibrillation (AF) is significantly associated with reduced risk for stroke, cardiovascular events and all-cause death. However, little is known whether late recurrence of AF after catheter ablation is associated with worse clinical outcomes.

Purpose

We aimed to clarify whether late recurrence of AF after catheter ablation is associated with major adverse cardiac and cerebrovascular events (MACCE).

Methods

We retrospectively investigated 2,737 participants (74.4% men, mean age 63.4±10.3 years, 62.7% paroxysmal AF) who received first catheter ablation for AF and completed follow-up more than 3 months after the procedure from AF Frontier Ablation Registry, a multicenter cohort study in Japan. We evaluated an association between late recurrence of AF after catheter ablation and first MACCE in cox-regression hazard models adjusted for known risk factors. MACCE were defined as stroke/transient ischemic attack (TIA), cardiovascular events or all-cause death. Late recurrence was defined as AF relapse more than 3 months after the procedure.

Results

During a mean follow-up period of 25.2 months, 2,070 patients (75.6%) were free from AF after catheter ablation and 122 patients (4.5%) had MACCE (ischemic stroke 18 [14.8%], hemorrhagic stroke 16 [13.1%], TIA 7 [5.7%], hospitalization for heart failure 19 [15.6%], acute coronary syndrome 19 [15.6%], hospitalization for other cardiovascular events 24 [20%] and all-cause death 19 [15.6%]). The MACCE occurred significantly more frequently in the recurrence group than in non-recurrence group (7.5% vs. 3.5%; hazard ratio [HR] 1.85; 95% confidence interval [CI] 1.28–2.65; P=0.001) (Figure). Multivariate analysis revealed that baseline age (HR 1.05; 95% CI 1.03–1.08; P<0.001), heart failure (HR 1.76; 95% CI 1.17–2.66; P=0.007), old myocardial infarction (HR 4.49; 95% CI 2.59–7.81; P<0.001), non-ischemic cardiomyopathy (HR 2.56; 95% CI 1.47–4.46; P=0.001), left atrial diameter (HR 1.22 per 5-mm increase; 95% CI, 1.06–1.41; P=0.006) and recurrence of AF (HR 1.69; 95% CI 1.17–2.44; P=0.005) were independently associated with the incidence of MACCE after catheter ablation.

Conclusion

In the Japanese multicenter cohort of AF ablation, late recurrence of AF was independently associated with increased MACCE, suggesting the significance of sinus rhythm maintenance by catheter ablation.

Kaplan-Meier curves for MACCE

Funding Acknowledgement

Type of funding source: None

B-Type natriuretic peptide predicts major adverse cardiac and cerebrovascular events after catheter ablation of atrial fibrillation: insights from AF frontier ablation registry

Background

High plasma B-Type natriuretic peptide (BNP) level is associated with cardiac events or stroke in patients with atrial fibrillation (AF). However, it is still unknown whether BNP predicts worse clinical outcomes after catheter ablation ofAF.

Purpose

We aimed to see if plasma BNP level is associated with major adverse cardiac and cerebrovascular events (MACCE) after catheter ablation of AF.

Methods

We retrospectively analyzed 1,853 participants (73.1% men, mean age 63.3±10.3 years, 60.7% paroxysmal AF) who received first catheter ablation of AF with pre-ablation plasma BNP level measurement and completed follow-up more than 3 months after the procedure from AF Frontier Ablation Registry, a multicenter cohort study in Japan. We evaluated an association between plasma BNP level before catheter ablation and first MACCE in cox-regression hazard models adjusted for known risk factors. MACCE were defined as stroke/transient ischemic attack (TIA), cardiovascular events or all-cause death.

Results

The mean plasma BNP level was 120.2±3.7 pg/mL. During a mean follow-up period of 21.9 months, 57 patients (3.1%) suffered MACCE (ischemic stroke 8 [14.0%], hemorrhagic stroke 5 [8.8%], TIA 5 [8.8%], hospitalization for heart failure 11 [19.2%], acute coronary syndrome 9 [15.8%], hospitalization for other cardiovascular events 8 [14.0%] and all-cause death 11 [19.2%]). Plasma BNP level of patients with MACCE were significantly higher than those without MACCE (291.7±47.0 vs 114.7±3.42 pg/mL, P<0.001). Multivariate analysis revealed that plasma BNP level (hazard ratio [HR] per 10 pg/mL increase 1.014; 95% confidence interval [CI] 1.005–1.023; P=0.001), baseline age (HR 1.052; 95% CI 1.022–1.084; P=0.001), heart failure (HR 2.698; 95% CI 1.512–4.815; P=0.001), old myocardial infarction (HR 3.593; 95% CI 1.675–7.708; P=0.001) and non-ischemic cardiomyopathy (HR 2.676; 95% CI 1.337 - 5.355; P=0.005) were independently associated with MACCE. At receiver-operating characteristic curve analysis, plasma BNP level before catheter ablation ≥162.7 pg/mL was the best threshold to predict MACCE (area under the curve: 0.71). Kaplan-Meier curve analysis (Figure) showed that the cumulative incidence of MACCE was significantly higher in patients with a BNP ≥162.7 pg/mL than in those with a BNP below 162.7 pg/mL (HR 4.85; 95% CI 2.86–8.21; P<0.001).

Conclusions

Elevation of plasma BNP level was independently related to the increased risk of MACCE after catheter ablation ofAF.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Bristol-Meiers Squibb

Effects of PCSK9 inhibitor on adverse limb outcomes in patients with critical limb ischemia

Background

The proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9-I), evolocumab, reduced the risk of cardiovascular event in patients with peripheral artery disease in FOURIER trial. However, the effects of evolocumab on favorable limb outcomes in patients with critical limb ischemia (CLI) is still unclear.

Purpose

The aim of this study was to evaluate the impacts of evolocumab on favorable limb outcomes and lipid profile in patients with CLI.

Methods

This was a single center, prospective observational study. A total of 39 patients with CLI were enrolled between November 2016 to May 2019. The subjects were divided into 2 groups based on evolocumab administration: evolocumab-treated group: E group (mean 69.4±11.7 years, n=14) and evolocumab non-treated group: Non-E group (mean 74.0±8.8 years, n=25). Baseline characteristics were assessed at admission. Lipid profile was evaluated at admission, 1, 3, 6, 12 and 18 months. The primary outcome was defined 18-month amputation-free survival (AFS). The secondary outcomes were defined 18-month overall survival (OS) and wound-free limb salvage. Mean follow-up period was 18±11 months.

Results

The patients in E group had greater reduction in levels of LDL cholesterol and non-HDL cholesterol than those in Non-E group over time. The reduction in MDA-LDL level was maintained at 1, 3, 6, 12 months, respectively. The 18-month AFS rate in the E-group was significantly higher than those in the Non-E group (log-rank p=0.02). The patients receiving evolocumab had a lower hazard regarding AFS (hazard ratio, 0.12; 95% confidence interval, 0.02–0.94; P=0.043) and a higher proportion of wound-free limb salvage at 12 months (E group [92%] vs Non-E group [57%], P=0.034) and 18 months (92% vs 52%, P=0.03). Otherwise, evolocumab administration was not associated with 18-month OS (log-rank p=0.053).

Conclusions

Evolocumab administration may be associated with the favorable outcome of 18-month AFS in the patients with CLI. Additionally, long-term administration of evolocumab over 12 months may improve wound-free limb salvage.

Effects of evolocumab on limb outcomes

Funding Acknowledgement

Type of funding source: None

Assessment of transporter-mediated efflux of nintedanib using in vitro cell line models of idiopathic pulmonary fibrosis

Objective: We aimed to investigate the involvement of efflux transporters, including multidrug resistant protein 1 (MDR1), multidrug resistance-associated protein 1 (MRP1), MRP2, and breast cancer resistance protein (BCRP), in the intracellular accumulation of the antifibrotic agent nintedanib in fibrotic lung cells. Methods: We used transforming growth factor-β₁ (TGF-β₁)-treated human lung fibroblasts (WI-38) and alveolar epithelial cells (A549) as in vitro models. The expression and activities of efflux transporters in TGF-β₁-treated WI-38 and A549 cells were evaluated using immunoblotting and flow cytometry. Cells were treated with nintedanib and then incubated with inhibitors of these transporters. The intracellular concentration of nintedanib was determined. Results: MDR1, MRP1, MRP2, and BCRP were found to be expressed in WI-38 and A549 cells with or without TGF-β₁ stimulation, with the exception of MRP2 in WI-38 cells. The efflux activities of these transporters were observed in these cells. MDR1 inhibitors significantly increased the intracellular accumulation of nintedanib, whereas MRP inhibitors did not show an effect. The BCRP inhibitor significantly increased the transporter activity in A549 cells but not in WI-38 cells. Conclusion: This study suggests that the efflux via MDR1 and BCRP is involved in the intracellular accumulation of nintedanib in fibrotic lung cells.

P6201Beneficial effect of ezetimibe-atorvastatin combination therapy in patients with a mutation in ABCG5 or ABCG8 gene

Background

Use of ezetimibe on top of statin therapy has been shown to be effective to reduce LDL cholesterol level in hypercholesterolemic patients. However, little is known regarding the individual variety of the effectiveness of ezetimibe. We hypothesized that hypercholesterolemic patients with a mutation in ABCG5 or ABCG8 gene exhibit better response to ezetimibe that those without, based on the fact that ezetimibe is hyper-effective for in patients with sitosterolemia caused by ABCG5 or ABCG8 genetic mutations.

Methods

Electronical medical record were reviewed in a total of 321 hypercholesterolemic patients (baseline LDL cholesterol = 192±46 mg/dl) prescribed ezetimibe 10 mg daily on top of atorvastatin 10mg daily who had undergone genetic analysis of ABCG5 or ABCG8 gene in our institute since 2006 to 2017. Pathogenicity of the variants were determined using standard variant filtering schema, including minor allele frequency, in silico annotation tools. Patients were divided into 2 groups based on the presence of ABCG5 or ABCG8 mutation. We compared the percent reduction of LDL cholesterol as well as the achieved LDL cholesterol levels between these 2 groups.

Results

We found 26 (8%) individuals who exhibit deleterious mutations in ABCG5 or ABCG8 gene. Baseline characteristics under the atorvastatin 10mg therapy were comparable in age, gender, and LDL cholesterol level between 2 groups. Under these conditions, percent reduction of LDL cholesterol in mutation positive group was significantly larger than that of mutation negative group (28±16% vs. 39±21%, p<0.05). As a result, the achieved LDL cholesterol level in mutation positive group was significantly lower than that of mutation negative group (87±29 mg/dl vs. 72±26% mg/dl, p<0.05).

Conclusion

These results suggest that ezetimibe-atorvastatin combination therapy might be more beneficial in hypercholesterolemic patients with a mutation in ABCG5 or ABCG8 gene.

3073Leveraging transcriptome sequencing for detecting novel disease-related pathways using human cardiac sarcoidosis myocardium biopsies

Background/Introduction

Cardiac sarcoidosis (CS) is one of the main causes of poor outcomes in patients with sarcoidosis, a systemic granulomatous disorder of complex etiology including a genetically susceptible host and specific exposure to disease-triggering antigens. Recently, transcriptome analysis using sarcoidosis peripheral monocytes was reported to be useful for exploring genetic susceptibility and novel disease-causing pathways. However, transcriptome sequencing has not been used to explore disease-related genes and pathways directly using human CS myocardial biopsies.

Purpose

This study aimed to identify transcriptome profiles and novel disease-related pathways of CS by comparing human CS myocardial biopsies with control samples using ribonucleic acid (RNA) sequencing (RNA-Seq).

Methods

We assessed 30 patients with suspected myocardial disorders who underwent transcatheter endomyocardial biopsies at our University Hospital, Japan. Of those, 7 were clinically diagnosed with CS, 9 with hypertrophic cardiomyopathy (HCM), and 14 with dilated cardiomyopathy (DCM). Messenger RNAs were extracted from cardiac muscle biopsies using the Ovation SoLo RNA-Seq System (NuGEN Technologies), according to the manufacturer's instructions. Sequencing was performed with coverage of approximately 20 million reads per sample using Illumina HiSeq 2000. Sequencing reads were mapped using the STAR 2-pass method with GRCh37 as the reference. The DESeq2 R package (version 3.8) was used for further analyses. Principal component analysis (PCA) on gene expression was conducted for detecting outliers such as non-muscular samples. Differential gene expression analysis was performed between the 7 patients with CS and 23 patients with cardiomyopathy (HCM and DCM, non-CS). Gene Ontology (GO) enrichment analysis was conducted to estimate possible disease-related pathways.

Results

We successfully sequenced 60 myocardial biopsy samples (original and biological duplicates) from 30 CS patients. Of these, 2 outlier samples shown by the PCA plot were removed, and 58 were used for further analyses. We found 243 genes that were differentially expressed between CS patients and non-CS patients. Top-rated genes were RP11–366M4.8, RELN, S100A6, WASF3and UCHL1. Pathway analysis using GO demonstrated enrichment oflymphocyte activation (P=4.8x10–16), organelle fission (P=6.1x10–14), the M phase of the mitotic cell cycle (P=2.2x10–13), nuclear division (P=2.4x10–13), mitosis (P=2.4x10–13) and T-cell activation pathways (P=1.2x10–12).

Conclusions

Our differential gene expression and pathway analysis results using human CS myocardial biopsies suggested that lymphocyte activation, specifically the T-cell activation pathway, is linked to CS pathogenesis. Further studies are needed to decipher the role of specific genes related to genetic susceptibility and/or pathways associated with CS occurrence.

P6202Serum sitosterol levels and ABCG5 and ABCG8 genetic mutations among Japanese dyslipidemic subjects

Background

Sitosterolemia, which is caused by ABCG5 or ABCG8 genetic mutations, is involved with marked increased concentrations of cholesterol as well as non-cholesterol plant sterols including sitosterol. Assessments of serum sitosterol level is critical to discriminate this disease from familial hypercholesterolemia (FH), which exhibits similar phenotypes except for elevated sitosterol levels. However, no prior data exist regarding the optimal cutoff value of serum sitosterol predicting the presence of sitosterolemia with double pathogenic mutations in ABCG5 or ABCG8 genes.

Methods

We retrospectively investigated consecutive 253 Japanese dyslipidemic subjects (mean age = 47.02 yr, male = 48.6%) with the assessments of serum sitosterol level as well as the presence of ABCG5 or ABCG8 genetic mutations in our institute since 2009 to 2018. Exome lesions of those 2 genes were sequenced, and pathogenicity of the identified genetic variants were determined using standard variant filtering schema, including minor allele frequency, in silico annotation tools. We divided the subjects into 3 groups based on the number of pathogenic mutations in ABCG5 or ABCG8 genes. We compared serum lipid values, including LDL cholesterol as well as serum sitosterol among those groups, and tried to determine the optimal cutoff value discriminating patients of sitosterolemia with double mutations from others.

Results

We identified 11 individuals with sitosterolemia with double mutations, 27 individuals with a single mutation, and 215 individuals without any mutations. Distribution of serum sitosterol exhibited skewed to the right (Figure). There was no significant correlation between serum sitosterol and other lipids, including LDL cholesterol. As expected, serum sitosterol level of patients with sitosterolemia exhibited significantly higher than those of any other groups (52.0 vs. 7.9 μg/ml, p=2.22×10–6, 52.0 vs. 2.8 μg/ml, p=2.275×10–8). 15 μg/ml was the optimal cut-off value, the sensitivity and specificity of which were 100%, and 99.6%, respectively.

Histgram of serum sitosterol

Conclusion

We suggest the cutoff sitosterol value of 15 μg/ml predicting the presence of sitosterolemia with double pathogenic ABCG5 or ABCG8 genetic mutations.

P5641Impact of lethal arrhythmias on medical castration in patients with prostate cancer

Background

Prostate cancer is the most common non-cutaneous malignancy in men and has been steadily rising in an aging society. Medical castration had been widely applied as a treatment for prostate cancer. Sex steroid hormones regulate cardiac ion channels. However, the proarrhythmic properties of medical castration have not been reported.

Methods

This prospective observational study consisted of 149 patients (75±6 years) who underwent hormonal therapy using gonadotropin-releasing hormone with or without anti-androgen for prostate cancer. The changes of electrocardiogram (ECG) findings during the therapy and the associations of ECG findings with lethal arrhythmias were studied.

Results

QT (394±32 to 406±39 ms, p<0.001) and QTc intervals (416±27 to 439±31 ms, p<0.001) significantly prolonged during the therapy as compared to baseline. Heart rate significantly increased during the therapy as compared to baseline (68±11 to 71±14 / min, p=0.006). PQ interval and QRS duration were similar before and during the therapy. During the hormonal therapy, 2 patients (1.3%) presented with torsades de pointes and ventricular fibrillation. The first patient was 71 year-old and the second patient was 70 year-old. The period of the therapy was 6 and 45 months, respectively. Both patients had no structural heart disease. The magnitude of QTc interval change during the therapy as compared to baseline (Δ QTc interval) was significantly greater in patients with VF than those without (p<0.001), however the magnitude of Δ heart rate, Δ PQ interval, and Δ QRS duration were similar between the 2 groups.

Conclusions

Medical castration significantly prolonged QT/QTc interval and could be a trigger of lethal arrhythmias in patients with prostate cancer.

P649Validation of clinical diagnostic criteria of familial hypercholesterolemia in Japan: evidence from a comprehensive genetic analysis

Background

Although awareness of familial hypercholesterolemia (FH) is increasing, this common, potentially fatal, treatable condition remains underdiagnosed. Japanese clinical diagnostic criteria of FH include LDL cholesterol level ≥180 mg/dl, Achilles tendon thickness (ATT) ≥9.0 mm, and family history of FH or premature coronary disease. Despite FH being a genetic disorder, genetic testing is rarely used, few data exist regarding the validation of those criteria, especially, by studies using comprehensive genetic analyses.

Methods

This study included 680 subjects (344 men, mean LDL cholesterol = 175 mg/dl) who underwent the full assessments for FH, including LDL cholesterol measurement, Achilles tendon X-ray, investigations for family history, and comprehensive genetic analyses on FH-associated genes (LDL receptor, PCSK9, APOB, and LDLRAP1) in our University Hospital since 2006 to 2018. The area under curve (AUCs) of receiver-operating characteristic (ROC) curve analyses predicting FH-mutation positive were compared among those determined by each component.

Results

ROC analyses revealed the optimal cutoff LDL cholesterol value for predicting the presence of FH-mutation was 181 mg/dl, and that of ATT was ≥7.0 mm. AUCs of each component (ATT, LDL cholesterol, and family history) were 0.827, 0.889, and 0.906, respectively, and the combination of all components increased it to 0.975. When adopting ATT ≥7.0 mm as one of the clinical diagnostic criteria, 13 individuals (2%) were newly classified as true-FH, whereas, 27 (4%) individuals were newly misclassified as FH.

Conclusion

The current Japanese clinical diagnostic criteria of FH were pretty well validated in our independent cohort. However, the threshold of ATT could be lowered to 7.0 mm to raise the sensitivity of its criteria.

P6339Sequential organ failure assessment score on admission predicts long-time mortality of the patients with acute heart failure

Background

Despite the remarkable advances in the treatment options of acute heart failure (HF), prognosis assessment remains an ongoing challenge. Previous studies revealed only a moderate accuracy of models predicting mortality. Sequential Organ Failure Assessment (SOFA) Score are widely used in the intensive care unit (ICU) to predict outcome and predicted higher long-time mortality in unselected patients in cardiac ICU. In addition, the American Heart Association Get With the Guidelines–Heart Failure (GWTG-HF) risk score allows for risk stratification of 30-day outcome for patients hospitalized with HF. The purpose of this study was to evaluate whether SOFA score on admission is useful for long-time mortality prediction in acute HF patients and also to assess the discriminative performance as compared with GWTG-HF risk score.

Methods

This was a single-centre, retrospective cohort study. Between January 2007 and December 2016, we screened eligible 661 consecutive patients with acute HF administered at our hospital. SOFA score on admission of 294 patients was able to calculate retrospectively. We enrolled 269 patients who could complete follow up evaluation for more than 1 year. Endpoint was all-cause mortality after admission. Additive information of SOFA score was evaluated by area under the curve (AUC), net reclassification improvement (NRI), integrated discrimination improvement (IDI) and decision curve analysis (DCA).

Results

The 269 patients were included in this study (78.5±10.9 years; 136 men; left ventricular ejection fraction [EF], 49.8±16.6%) during a mean follow-up of 32.1±22.3 months. Patients with all-cause death had higher SOFA score (4.2±2.3 versus 2.8±1.8, p<0.001; AUC, 0.689) and GWTG-HF risk score (44.0±7.6 versus 38.1±7.9, P<0.001, AUC, 0.692).

Kaplan-Meier survival analysis demonstrated higher SOFA scores (P<0.001) and GWTG-HF risk scores (P<0.001) appears to be related to increase probabilities of all cause death. A multivariate Cox proportional hazard model were made with adjustment for SOFA score, GWTG-HF risk score, age, gender and ejection fraction. As a result, SOFA score (hazard ratio [HR] 1.227; 95% confidence interval [CI], 1.130 to 1.326; P<0.001), GWTG-HF (HR, 1.054; 95% CI, 1.029 to 1.078; P<0.001) and age (HR, 1.069; 95% CI 1.048 to 1.092; P<0.001) were independent predictors of all cause death and HR of SOFA score was the highest in these parameters. Incorporating SOFA score into GWTG-HF score yielded a significant NRI (0.528 (95% CI 0.291 to 0.765) and IDI (0.046 (95% CI 0.020 to 0.072). In DCA, compared with the reference model, the net benefit for SOFA score model was greater across the range of threshold probabilities.

Conclusions

The SOFA score, simple and validated mortality risk score can predict long-term all-cause mortality in patients with acute HF. Discriminative performance metrics such as NRI, IDI and DCA were improved on incorporation of the SOFA score for prediction of mortality.

P6199Lipoprotein(a) and risk of chronic kidney disease among 4,235 Japanese hospitalized patients

Background

Lipoprotein (a) [Lp(a)] has been shown to be associated with the development of chronic kidney disease (CKD) among various ethnicities. In addition, recent Mendelian randomization studies have suggested that Lp(a) seems to be causally associated with CKD. However, few data exist regarding this issue among Japanese population.

Purpose

We aimed to investigate the association between serum Lp(a) and the CKD among Japanese population.

Methods

We retrospectively investigated 6,130 subjects whose serum Lp(a) had been measured for any reason (e.g. any operations which needs bed rest for a long duration, risk factors for atherosclerosis such as hypertension or diabetes) at our University Hospital from April 2004 to March 2014. We excluded 1,895 subjects due to the lack clinical data. We assessed their Lp(a), LDL cholesterol, HDL cholesterol, triglycerides, presence of hypertension, diabetes, chronic kidney disease, smoking, body mass index, presence of coronary artery disease (CAD), and presence of CKD (stage 3 or greater).

Results

When the study subjects were divided into 5 groups based on their CKD stage, there was a significant trend among their serum Lp(a) levels (P-trend = 2.7×10–13). Under these conditions, multiple regression analysis showed that Lp(a) was significantly associated with CKD [odds ratio (OR): 1.12, 95% confidence interval (CI): 1.08–1.17; p=1.3×10–7: per 10mg/dL)., independent of other classical risk factors, including age, gender, body mass index, hypertension, diabetes, smoking, LDL cholesterol and triglycerides. Under these conditions, Lp(a) was significantly associated with CAD [OR: 1.11, 95% CI: 1.06–1.16; p=1.7×10–6: per 10mg/dL), independent of the presence of CKD.

Conclusion

Serum Lp(a) was associated with the development of CKD independent of other classical risk factors among Japanese population as well.

P1535Clinical impact of carotid plaque score rather than carotid intima-media thickness on atherosclerotic cardiovascular disease

Background

Carotid intima-media thickness (cIMT) assessed by ultrasound has been widely accepted as a surrogate marker of atherosclerotic cardiovascular disease. On the other hand, carotid plaque score (cPS) reflecting throughout the carotid artery plaque burden may be better marker.

Methods

We retrospectively examined 2,035 patients who underwent carotid ultrasonography between January 2006 and December 2015 at our University Hospital. Median follow-up period was 4 years. We used Cox models that adjusted for established risk factors of ASCVD, including age, gender, hypertension, diabetes, smoking, and serum lipids to assess the association of cIMT as well as cPS with major adverse cardiac events (MACE). MACE was defined as all-cause mortality or rehospitalization for a cardiovascular-related illness

Results

During follow-up, 243 participants experienced MACE. After adjustment for established risk factors, cPS was associated with MACE (hazard ratio [HR] = 3.38 for top quintile vs. bottom quintile of cPS; 95% confidence interval [CI] 1.82 to 6.27; P-trend = 1.4×10–8), while cIMT was not (HR = 0.88, P=0.57). Addition of the cPS to established risk factors significantly improved risk discrimination (C-index 0.726 vs. 0.746; P=0.017)

Conclusion

As a marker, cPS, rather than cIMT can identify 20% of individuals who are at more than three-fold increased risk for MACE. Targeting diagnostic or therapeutic interventions to this subset may prove clinically useful.

Abstract OT2-07-05: A phase III trial to compare eribulin mesylate + trastuzumab (H) + pertuzumab (P) with paclitaxel or docetaxel + HP for HER2-positive advanced or metastatic breast cancer (JBCRG-M06/ EMERALD)

Background: Docetaxel + Trastuzumab (H) + Pertuzumab (P) provided progression-free survival (PFS) and overall survival (OS) benefits in HER2-positive advanced or metastatic breast cancer (AMBC) in the CLEOPATRA study as a first-line therapy. However, long-term administration of docetaxel at a dose of 75 mg/m2 every 3 weeks in AMBC patients (pts) is difficult due to the toxicities. Eribulin mesylate (E) is a well-tolerated microtubule inhibitor, and we have reported the efficacy and safety of EHP regimen as first- and second-line therapy for AMBC in a multicenter, phase II study (JBCRG-M03/UMIN000012232). In this M06 study, we address the clinical question as to which is the better chemotherapy partner for HP as first line regimen, in terms of efficacy, toxicity and QOL.

Methods: JBCRG-M06 is a multicenter open-label randomized phase III study for HER2-positive AMBC pts who have received no prior chemotherapy except for the HER2- Antibody-Drug Conjugate (ADC). Pts will be randomized 1:1 to E (1.4mg/m2 on day 1 and 8) + H (8 mg/kg loading dose followed by 6 mg/kg) +P (840 mg loading dose followed by 420 mg) q3wks or standard taxanes (docetaxel 75mg/m2 on day1 or paclitaxel 80mg/m2 on day 1, 8 and 15) + HP q3wks. Stratification factors for randomization are; presence of visceral metastases, number of prior taxanes on perioperative adjuvant treatment, and treatment with prior anti-HER2-ADC. Primary endpoint is PFS and secondary endpoints include overall response rate, duration of response, OS, patient-reported outcomes (PRO) relating to QOL and peripheral neuropathy, new-metastases free survival, and safety. Translational research to search for biomarker for individual precision therapy will be performed. Main eligibility criteria are as follows: pts with HER2-positive AMBC, female aged 20-70 years old, ECOG PS of 0-1, LVEF ≥ 50% at baseline and adequate organ function. Pts who had progressive MBC within 6 months after the end of primary adjuvant systemic chemotherapy are excluded. The sample size was calculated by type1 error (2-sided) of 0.05 and 80% power to estimate the noninferiority margin 1.33 with an expected median PFS of 14.2 months. The target number of pts is 480 recruited over the duration of 3-years. The first patient in was achieved on August 2017. (ClinicalTrials.gov Identifier:NCT03264547).

Citation Format: Masuda N, Yamashita T, Saji S, Araki K, Ito Y, Takano T, Takahashi M, Tsurutani J, Koizumi K, Kitada M, Kojima Y, Sagara Y, Tada H, Iwasa T, Kadoya T, Iwatani T, Hasegawa H, Morita S, Ohno S. A phase III trial to compare eribulin mesylate + trastuzumab (H) + pertuzumab (P) with paclitaxel or docetaxel + HP for HER2-positive advanced or metastatic breast cancer (JBCRG-M06/ EMERALD) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-07-05.

Abstract P2-09-28: New quantitative diagnostic method by fluorescence nanoparticle for HER2 positive breast cancer treated with neoadjuvant lapatinib and trastuzumab: The Neo LaTH study (JBCRG-16TR)

Background: HER2 (human epidermal growth factor receptor 2) testing performed by IHC (immunohistochemical) methods and FISH (fluorescence in situ hybridization) is semi-quantitative. Exact quantification of HER2 is needed to predict which patients are more or less likely to response to anti HER2 therapy. To improve the method for cancer patients' HER2 status, we developed a novel fluorescence IHC method using new fluorescence nanoparticle. The fluorescent intensity of this new nanoparticles, termed phosphor-integrated dot (PID), was approximately 100-fold brighter than that of Quantum dots. Because of its increased brightness and analyzing technology, this PID-based fluorescent IHC(IHC-PIC) has an ability of quantifying the biomarker protein in the cancer tissue sample at single particle level. In this study, the primary objective was to investigate if pathological complete response (pCR) rate in HER2- positive breast cancer treated by trastuzumab and lapatinib containing neoadjuvant systemic therapy would depend on the level of HER2, EGFR, HER3, Ki67, ER and PgR protein quantified by this new method.

Methods: The Neo-LaTH study is a randomized phase II multicenter trial evaluating the efficacy and safety of lapatinib and trastuzumab followed by lapatinib and trastuzumab plus weekly paclitaxel with or without prolongation of anti-HER2 therapy prior to chemotherapy (18 weeks vs. 6 weeks). The primary endpoint was the comprehensive pCR rate. We evaluated the HER2, EGFR, HER3, Ki67, ER and PgR amount by nano-patho method using PID in formalin-fixed paraffin-embedded core biopsy samples taken at diagnosis retrospective analysis. Univariate and multivariate analyses were performed to determine the association between pCR and variables, including HER2, EGFR, HER3, Ki67, ER and PgR nano-patho score and clinicopathological factors including histological grade, tumor status, nodal status and HER2 FISH ratio.

Results: A total of 96 tumor samples from patients were used for the present analysis.The pCR rate was 60.4%. We obtained the images of only PID signal by the image analyses, and calculated the number of PID particles in a cell and defined it as IHC-PID score that reflects the level of HER2, EGFR, HER3, Ki67, ER and PgR protein expression in cancer cells. Univariate analysis showed that HER2 IHC-PID score(p&lt;0.0001), ER IHC-PID score(p=0.009) and PgR IHC-PID score(p=0.019) were associated with pCR and multivariate analysis showed that HER2 IHC-PID score was significantly associated with pCR (adjusted odds ratio, 0.990 [95% CI, 0.984–0.996]; P &lt; .0001).

Conclusion: We successfully performed the quantitative IHC-PID for HER2, EGFR, HER3, Ki67, ER and PgR. And we propose using HER2 IHC-PID score as a predictive factor for trastuzumab and lapatinib containing neoadjuvant systemic therapy. This quantitative diagnostic method would be expected to contribute to the development of a molecular therapeutic strategy.

Citation Format: Tada H, Miyashita M, Gonda K, Watanabe M, Suzuki A, Watanabe G, Harada N, Sato A, Hamanaka Y, Masuda N, Toi M, Ohno S, Bando H, Ishiguro H, Inoue K, Yamamoto N, Kuroi K, Ohuchi N, Ishida T. New quantitative diagnostic method by fluorescence nanoparticle for HER2 positive breast cancer treated with neoadjuvant lapatinib and trastuzumab: The Neo LaTH study (JBCRG-16TR) [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 P2-09-28.

Abstract P1-01-03: Interim analysis of the validation study on the clinical usefulness of the ICG fluorescence method for detecting sentinel lymph nodes in early breast cancer compared with the RI method (fICG-BR02)

Background: Sentinel lymph node (SLN) biopsy guided by radioisotope (RI), blue dye or in combination methods is common. A high identification rate is reported for the RI-guided method. On the other hand, it has the demerits of radiation exposure, being expense, and it can only be used in a radiation-controlled area. The blue dye method, however, is safe and inexpensive, but the identification rate is lower compared with the RI method and requires training. The indocyanine green (ICG) fluorescent method involves the application of the fluorescing property. Lymph flow can be traced from outside the body with a photodynamic eye (PDE) camera simultaneously with an operation procedure. The ICG method is safe, inexpensive and requires little training, therefore its use will be widely permitted in any general hospitals. Recently, based on several retrospective clinical trials, the identification rate with the ICG fluorescent method has been reported to be equal to or greater than the RI method. The purpose of this multicenter study is to prospectively assess the diagnostic performance of SLN biopsy using the ICG fluorescence technique compared with RI.

Materials and methods: In this validation study, the patients aged from 20 to 75 years-old with operable primary invasive breast cancer (cT1c-2N0M0) have been nominated and required the written informed consent.

All candidates underwent SLN biopsy using the combined methods with RI and ICG fluorescence. The target sample size was 840 patients to evaluate the sensitivity of ICG method as a primary endpoint, and after 200 patients were enrolled we analyzed the identification rate and the SLN-positive rate of the RI and ICG methods respectively as the interim analysis planned beforehand.

Results: Two hundred eligible patients were enrolled in this study from May 2011 to February 2012. Their median age was 53.0 years (range: 27-74 years). The number of patients with cT1c was 106 and that with cT2 was 94. The identification rate of the RI and the ICG method was 97% (194/200) and 96% (192/200) respectively. Of the 194 patients that were identified with the RI method, 186 (95.9%) were also identified with the ICG method. ICG identified 6 patients that were not identified by RI. On the other hand, RI identified 8 patients that were not identified by ICG. The SLN-positive rate was 25.5% (51/200). This rate was higher than we expected. Of the 51 patients with positive metastatic lymph nodes, 23 patients (21.7%) had cT1c breast cancer and 28 (29.8%) had cT2 breast cancer. The positive rate of the first SLN was 23.5% (47/200) and tumor cells skipped to the second or further tier in four cases (2%).

Conclusions: The ICG-guided SLN biopsy procedure achieved a high identification rate almost equal to that with the RI method. Using this combination method, the identification rate was 100%. We will assess the sensitivity and the additive effect of combining the ICG fluorescence method with the RI method, etc., when all 840 patients have been enrolled (UMIN000005167).

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-01-03.

Abstract P3-05-16: Quantitative diagnostic technology for HER2 positive breast cancer by molecular imaging: The potential predictive factor of anti-HER2 therapy

Background: Anti-HER2 therapy contributes to improvement of the clinical outcome in HER2-positive patients. However, current studies have reported the resistance to trastuzumab. To diagnose HER2 expression level, immunohistochemical (IHC) method with 3,3’-diaminobenzidine (IHC-DAB) staining is widely used, but is not quantitative and classifies tumors into only 4 categories. Additionally, the epitopes of trastuzumab and most antibodies used for IHC-DAB are different. These problems might induce a gap between diagnostics and therapeutic efficacy. To improve the method for cancer patients’ HER2 status, we developed a novel IHC method with trastuzumab conjugated with fluorescent nano-particles quantum dots (QDs) by single-particle imaging using tissue samples from patients with clinical information.

Methods: We prepared two kinds of QD-conjugated antibody complexes for IHC with QDs (IHC-QD). One was a QD-conjugated trastuzumab, the other was a QD-conjugated human IgG for control. We performed the several steps of antigen-antibody reaction by two kinds of QD-conjugated antibody probes for 37 human breast cancer specimens. The QD signal reflected HER2 expression level was observed by the optical system that consisted of an epi-fluorescent microscope with EM-CCD camera.

Results: We successfully obtained the images of only QDs signal by the image analyses, and calculated the number of QD particles in a cell and defined it as IHC-QD score that reflects the level of HER2 protein expression in cancer cells. In comparing IHC-QD scores with IHC-DAB scores, cases with a score of 0 and 1 by IHC-DAB had low scores of IHC-QD (0.01-0.67), being in narrow range. On the other hand, those with a score of 2 varied widely, with IHC-QD scores of 0.06 to 16.98, and those with a score of 3 also varied, from 0.18 to 18.81. In some of the sample with IHC-DAB score of 2 and 3, the binding of trastuzumab to these cancer cells is very weak although they are candidate for trastuzumab therapy in present HER2 diagnostic criteria. In comparison between FISH and IHC-QD scores, the straight-line approximation curve shows that both quantitative scores, FISH (0.96-8.76) and IHC-QD (0.01-18.81) are well correlated (R = 0.83, p&lt;0.001). In analyzing the therapeutic efficacy in 14 metastatic breast cancers treated with trastuzumab according to IHC-QD or FISH or IHC-DAB scores, IHC-QD score was correlated with time to progression (TTP) more than FISH and IHC-DAB scores.

Table 1Diagnostic methodsPatient numberTime to progression, median(range)P valueIHC-DAB  0.207Score 236 (3-9) Score 31112 (3-60) FISH  0.577Low score712 (5-60) High score79 (3-52) IHC-QD  0.094Low score76 (3-60) High score724 (3-52) Comparison between IHC-QD or FISH or IHC-DAB and the therapeutic efficacy with trastuzumab

Althogh the sample size was small, this result suggests that the IHC-QD score has a potential role as predictive factor for trastuzumab therapy.

Conclusion: We performed the precisely quantitative IHC using trastuzumab-conjugated QDs and single-particle imaging analysis, and propose using IHC-QD as a predictive factor for trastuzumab therapy. This new diagnostic method would be expected to contribute to the development of a therapeutic strategy.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-05-16.

Phasic synaptic incorporation of GluR2-lacking AMPA receptors at gonadotropin-releasing hormone neurons is involved in the generation of the luteinizing hormone surge in female rats

Reproductive success depends on a robust and appropriately timed preovulatory luteinizing hormone (LH) surge, which is induced by the activation of gonadotropin-releasing hormone (GnRH) neurons in response to positive feedback from increasing estrogen levels. Here we document an increase in postsynaptic GluR2-lacking Ca2+ -permeable AMPA-type glutamate receptors (CP-AMPARs) at synapses on GnRH neurons on the day of proestrus in rats, coincident with the increase in estrogen levels. Functional blockade of CP-AMPARs depressed the synaptic responses only on the day of proestrus and concomitantly attenuated the LH surge. Thus, the phasic synaptic incorporation of postsynaptic CP-AMPARs on GnRH neurons is involved in the generation of the LH surge.