Assessment of maxillary sinus fluid volume for postmortem diagnosis of drowning

INTRODUCTION

Drowning is a comprehensive and exclusive diagnosis at autopsy. Autopsy findings such as pleural effusion and waterlogged lungs contribute to the diagnosis. Herein, we aim to reveal the practical usefulness and postmortem changes of the maxillary sinus fluid volume to diagnose drowning.

METHODS

We evaluated 52 drowning and 59 nondrowning cases. The maxillary sinus fluid volume was measured using a computed tomography (CT) scan, and pleural effusion volume and lung weight were manually measured at autopsy. The utility of these three indices for diagnosing drowning and its postmortem changes was evaluated.

RESULTS

The maxillary sinus fluid volume was significantly higher in drowning cases than in other external causes and cardiovascular death cases. Receiver operating characteristic curve analysis revealed that a total maxillary sinus fluid volume >1.04 mL more usefully indicated drowning (odds ratio, 8.19) than a total pleural effusion volume >175 mL (odds ratio, 7.23) and a total lung weight >829 g (odds ratio, 2.29). The combination of maxillary sinus fluid volume and pleural effusion volume more effectively predicted drowning than one index alone. Moreover, the maxillary sinus fluid volume was less influenced by the postmortem interval than the other two indices up to a week after death.

CONCLUSION

Maxillary sinus fluid volume can be more useful than pleural effusion volume and lung weight with higher sensitivity and odds ratio for diagnosing drowning.

IMPLICATIONS FOR PRACTICE

Fluid accumulation in both the maxillary sinuses strongly predicts drowning in the postmortem imaging.

Desmoglein 2 mutant mice reproduce arrhythmogenic right ventricular cardiomyopathy patients' phenotype

Background

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is inherited cardiac disease with unresolved treatment. ARVC is progressive and leads to lethal arrhythmias and terminal heart failure. Most often encountered ARVC mutations are in desmosomal genes [1].

Purpose

We aimed to generate transgenic mice with exact copy of genetic defects found in Japanese cohort of ARVC patients, describe the phenotype, and identify target for curative therapy.

Methods

CRISPR/Cas9 genome editing was used to generate knock-in mice with the two most common point mutations in Japanese ARVC patients: DSG2 292R>C and 494D>A [2] (mouse equivalent positions are 297R and 499D, respectively). To analyze the phenotype of mice we used imaging techniques - cardiac echography and MRI as well as telemetry, treadmill, immunohistochemistry, confocal microscopy, histology, Western blot.

Results

In vivo observations of transgenic mice demonstrated inequalities in phenotypical presentation between the two mutations. Some of 297C mice (both hetero- and homozygous) died suddenly, starting from the age of 9 weeks, in contrast to surviving all 499A carriers. Dissection of suddenly died mice reveals enlarged cardiac cavities, mainly in the right heart. In addition, 297C homozygous hearts present with pale zones scattered all over the heart. Paraffin sections from this hearts stained with hematoxilin/eosin and Masson's trichrome show myocardial areas with absent myocytes, collagen accumulation and calcifications. With exception of homozygous 297C mice, spontaneous development of cardiac phenotype in Dsg2 knock-in mice starts after 25th weeks of age. Both mutant mice gradually developed cardiac dysfunction (echography and MRI, Fig. 1) and echographically visible left ventricular wall infiltrations. Heterozygous 297C mutation produces more severe phenotype that develops earlier. Similar to human ARVC, the degree of cardiac damage vary significantly. It is known from the human ARVC that physical activity aggravates the ARVC phenotype and may cause sudden cardiac death. To evaluate the effect of physical stress on the phenotype of Dsg2 knock-in mice we subjected 11 weeks old animals on treadmill exercise. Training for 8 weeks provoked development of heart failure in both 297C and 499A mutant mice, significantly earlier than natural progress of the phenotype. No mouse died suddenly. Telemetry experiment demonstrated electrical instability in 297C homozygous hearts showing conduction and rhythm abnormalities (Fig. 2). Apoptosis was detected in both mutant mice by TUNEL staining and confocal microscopy. Dsg2 protein expression was not affected by the mutations.

Conclusion

We generated mouse model of ARVC that reproduces exact genetic defect of the human disease. There are significant similarities between our model and ARVC patients' phenotype.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Japanese KAKENHI funding

Calmodulinopathy is a common cause of critical cardiac phenotypes in fetus and infancy

Background

Cardiac calmodulinopathy is a life-threatening arrhythmia syndrome which presents several phenotypes of inherited primary arrhythmia syndrome (IPAS), and caused by mutations in calmodulin-encoded genes (CALM1–3). We aimed clarify the frequency and their clinical characteristics of calmodulinopathy in our IPAS cohort.

Methods

By using next generation sequencing, we screened arrhythmia related genes including calmodulin-encoding genes in 322 unrelated symptomatic children (0–12 years) who were suspected as IPAS; they included 40 cases with lethal arrhythmic attacks (LAE) under 6-year-old. After gene screening, we investigated their physiological and clinical characteristics about mutation carriers.

Results

Among 322 children, we identified 6 mutations of calmodulin-encoded genes in 9 probands (2.8%); one CALM1 in 2 probands (N98S), and 5 CALM2 in 7 probands (E46K, D96V, D96G, N98S, E141K). Their clinical diagnoses were long QT syndrome (LQTS, n=4), catecholaminergic polymorphic ventricular tachycardia (CPVT, n=3) and both (n=2). Their age of diagnosis ranges at 0–9 with the median of 5 years. There were three major clinical phenotypes; 1) CALM2-D96V, and E141K: two infants with advanced atrio-ventricular block, significant QTc prolongation, severe heart failure from their fetal period – both of them deceased within 1.5-year-old. Their clinical phenotypes resembled classical Timothy syndrome caused by CACNA1C mutations. 2) CALM1-N98S (n=2), CALM2-N98S (n=2), and CALM2-D96G: four preschoolers with LAEs and one syncope: all of them were 3–5 years old. In addition, a T wave morphology of CALM2-D96G carrier was very similar to LQT1. 3) CALM2-E46K (n=2): two were first diagnosed with neurological and developmental disorders, and showed phenotype of CPVT: their cardiac phenotypes were milder compared with that of 1) or 2). Overall, these phenotypes seemed to be mutation specific (indicated in figure). Their cardiac features were severer, and the onset of LAEs was earlier compared with other genotypes of LQTS/CPVT. As the treatment, β-blocker was effective for control of LAEs.

Conclusion

Cardiac calmodulinopathy presented serious and potentially lethal phenotypes in fetus or infancy. To prevent cardiac death in them, we must correctly diagnose and start the treatment as earlier as possible.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): MEXT KAKENHI from the Ministry of Education, Culture, Sports, Science, and Technology of Japan

Different prognosis of ARVC patients between DSG2 and PKP2 variant carriers

Background

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy mainly caused by desmosomal gene variants. In Europe and North America, pathogenic variants in PKP2 were identified in most of the ARVC patients. On the other hand, we have reported that the genetic backgrounds of ARVC in Japanese were different from those in European; pathogenic variants in DSG2 were predominant in Japanese. Genotype-phenotype correlations, however, have not been clarified yet.

Purpose

In this study, we aimed to examine whether the genotype affect the phenotype and outcome in Japanese ARVC patients.

Methods and results

This study included 167 Japanese ARVC patients who received genetic testing (128 males [77%]). Their median age at diagnosis was 44 [24–55] years old and median follow-up duration was 10 [4–21] years. We found 90 patients with pathogenic variants: 52 in DSG2 (31%), 30 in PKP2 (18%), 3 in DSP (1.8%), 1 in DSC (0.6%), 1 in JUP (0.6%) and 3 in DES (1.8%). The age of the first sustained ventricular arrhythmia (SVT) were older in the patients with DSG2 than those with PKP2 variants (48±15 years vs. 35±15 years, P=0.008) but younger in DSG2 variant carriers at the first hospitalization for heart failure (41 [22–61] years vs. 67 [61–74] years, P=0.03). The left ventricular ejection fractions of DSG2 variant carriers were significantly lower at diagnosis than that of PKP2 (52 [41–60] % vs. 61 [56–66] %, P=0.002). Kaplan-Meier survival curve for lethal arrhythmic events including SVT, ventricular fibrillation and sudden death revealed that the event rate of DSG2 variant carriers was significantly lower than that of PKP2 (log-rank test, P=0.02) (Fig. 1).

Among 11 patients who had both SVT and hospitalizations for HF, 7 PKP2 variant carriers had SVT first, then, hospitalized for HF (48 [35–53] years and 67 [55–71] years, P=0.02). Contrary, the clinical course of 4 DSG2 variants carriers were different from those with PKP2 (54 [40–68] years for SVT and 65 [56–70, P=0.1] years for HF) (Fig. 2).

Conclusion

The patients with DSG2, which is the major causative gene for ARVC in Japanese, show different phenotype and outcome from those with PKP2. We should examine the effect of variants on the prognosis of ARVC patients in more large population including various ethnics.

Funding Acknowledgement

Type of funding sources: None.

Early onset of heart failure in Japanese ARVC patients with pathogenic desmosomal gene variants

Background

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy mainly caused by desmosomal gene variants. Although there are a lot of reports regarding to European ARVC patients, the ones in Asian are a few, and the characteristics of Asian ARVC have been still unclear. We have reported that the genetic backgrounds in Japanese ARVC patients were different from those in European ones. In this study, we aimed to examine the phenotype and outcome of Japanese ARVC patients with specific genetic backgrounds.

Methods and results

This study included 104 Japanese ARVC patients who were diagnosed as definite in the 2010 Task Force Criteria for ARVC and received genetic analysis (79 males [76%]; median age at diagnosis, 40 years [IQR 22–53 years].) Fifty-seven patients carried variants in desmosomal genes classified as pathogenic based on ACMG guideline: 30 in DSG2 (29%), 22 in PKP2 (21%), 2 in DSC2 (2%) and 3 in DSP (3%). The median age of diagnosis was significantly younger in the patients with the pathogenic variants than in those without (37 years [IQR 21–49 years] vs. 46 years [IQR 34–58 years], P=0.01). During a median follow-up of 9.3 years (IQR 3.5–20.9 years), 10 patients died and 2 were received heart transplantation. Sixty-two suffered lethal arrhythmic events including cardiopulmonary arrest, ventricular fibrillation, sustained ventricular tachycardia and appropriate shocks by implantable cardioverter defibrillator. Twenty-two were hospitalized for heart failure. There was no difference in these events rate between the two groups. However, survival analysis revealed that patients with pathogenic variants hospitalized for heart failure significantly earlier in their life than those without (P=0.04, log-rank test, Figure 1).

Conclusions

The Japanese ARVC patients with pathogenic variants in desmosomal genes are diagnosed and hospitalize for heart failure at younger age than those without. These findings have not been reported in other ethnics. Our study warns that we should be cautious for not only the prevention of lethal arrhythmic events but also the progress of the heart failure in Japanese ARVC patients with pathogenic variants.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Japan Agency for Medical Research and Development Figure 1

Preclinical proof-of-concept study: antisense-mediated knockdown of CALM as a therapeutic strategy for calmodulinopathy

Background

Calmodulin (CaM) is a ubiquitous Ca2+ sensor molecule encoded by three distinct calmodulin genes, CALM1–3, and has an important role for cardiac ion channel function. Recently, heterozygous missense mutations in CALM genes were reported to cause a new category of life-threatening genetic arrhythmias such as long-QT syndrome (LQTS) and catecholaminergic polymorphic ventricular tachycardia (CPVT), which is called as “calmodulinopathy”. The patients with calmodulinopathy show poor prognosis and there is no effective treatment for them.

Purpose

Considering the dominant-negative effect of mutant calmodulin proteins produced by heterozygous missense mutations in CALMs, we aimed to prove the concept of antisense-based therapy to treat calmodulinopathy using human iPS cell-derived cardiomyocyte (hiPSC-CM) model.

Methods

We designed multiple locked nucleic acid (LNA) gapmer-antisense oligonucleotides (ASOs) targeting CALM2 and analyzed the silencing efficiency and toxicity in cultured cells to select the most potent ASO. Using CMs differentiated from hiPSCs which were generated form a 12-year-old boy with LQTS carrying a heterozygous CALM2-N98S mutation, CALM2 expression and action potentials (APs) were analyzed to evaluate the efficacy of ASOs.

Results

We identified several ASOs which reduced CALM2 expression without affecting cell viability in human cultured cells (HepG2) (ASO 50 nM, n=2; Figure 1A). Considering further experiments in vivo mouse model, we investigated the CALM2 silencing activity in mouse cultured cells (3T3-L1) without transfection (free-uptake) (ASO 1 μM, n=2; †ASOs have homologous sequence between human and mouse; Figure B). After free-uptake CALM2 silencing analysis in 3T3-L1 cells, we identified that ASO #2 has the most potent CALM2 silencing activity and low cytotoxicity (Figure 1B). ASO #2 effectively reduced CALM2 expression even in hiPSC-CMs (ASO(−): n=3, lipofection: n=4, free-uptake: n=3; P<0.05; Figure 1C). In action potential recordings, we demonstrated that ASO #2 ameliorated prolonged AP durations (APD90) in N98S-hiPSC-CMs at 0.5 Hz pacing (ASO(−): 666±123 ms (n=7), lipofection: 329±21 ms (n=8), free-uptake: 388±34 ms (n=12); P<0.05; Figure 1D).

Conclusion

Our results using patient-derived hiPSC-CM model suggest that ASO-based therapy might be a promising strategy for the treatment of calmodulinopathy.

Figure 1

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Nissan Chemical Corporation

Clinical aspects of pediatric Brugada syndrome

Introduction

Brugada syndrome (BrS) is an inherited arrhythmia characterized by a coved-type ST elevation and sudden death, especially in middle-aged males and more common in Asia. Mutations in SCN5A are detected in 15–20% and reported to be associated with poor prognosis. Among children, BrS is rare and the risk factors in pediatric BrS are unknown, especially in Asian population.

Purpose

The purpose of this study is to elucidate the risk factors for fatal arrhythmic events in Japanese pediatric patients with BrS.

Methods

We enrolled 52 Japanese children with BrS younger than 20 years, and performed genetic analysis and collected the clinical information.

Results

The mean age of initial symptoms was 10.7±5.5 years, and the mean follow-up period was 3.9±5.5 years. Ninety percent of patients were probands. No subjective symptom was confirmed in 28 of the patients, but aborted cardiac arrest (ACA) in 4, ventricular tachycardia in 4, ventricular fibrillation in 1, and syncope in 11. We identified mutations in SCN5A in 63%. There was no significant gender difference in ≤10 years, but a significant male predominance appeared in >10 years. And no gender difference was confirmed in the incidence of severe cardiac events in ≤10 years.

Conclusion

No gender difference was confirmed in ≤10 years in this study about Asian children. And being girls did not reduce the risk in ≤10 years. The frequency of SCN5A mutations was higher than adults, but decreased from childhood (68%) to adolescence (59%). In BrS, genetical and environmental factors may be more effective in childhood and adulthood, respectively.

Funding Acknowledgement

Type of funding source: None

Long-read sequence confirmed a large deletion of MYH6 and MYH7 in a family with atrial septal defect

Background

Genome structural variants (SVs) have larger effect on human genome functions than single nucleotide variants (SNVs). Although short-read sequencing (SRS) is current major next generation sequencing method and has given us a great benefit to elucidate the genetic background of inherited diseases, it does not detect SVs accurately. Long-read sequencing (LRS) produces tens to thousands of kilobases reads and detects the breakpoints of complex SVs. This study aimed to confirm a large deletion, which was suspected by SRS, using LRS by Oxford Nanopore technology (ONT).

Methods

Genomic libraries for SRS was prepared with HaloPlex. Targeted SRS was performed for 58 genes with MiSeq. Genomic libraries for LRS were prepared using the Ligation sequencing 1D kit SQK-LSK109 (ONT). Whole genome LRS was performed with GridION X5 and R9.4 flow cells (ONT).

Results

The patient was a five-month-old boy with atrial septal defect (ASD) and atrial tachycardia. Though SRS failed to identify any causative SNVs, the results with SureCall software (Agilent) suspected a deletion between exon 3 to exon 26 in MYH6 encoding α heavy chains of cardiac myosin. The variants in MYH6 are known to be associated with ASD. Because a deletion between MYH6 exon 26 and MYH7 exon 27 was reported as esv2748480 on the Database of Genomic Variants, we performed long-range PCR from MYH6 intron26 to MYH7 exon26 and found an abnormal 1.5K bases PCR product only in the case. Due to high homology of MYH6 and MYH7, Sanger sequencing failed to detect the break point.

In LRS, 3 flow cells generated 3.8M base-called reads containing 42G bases with N50 of 13K bases. We used NGMLR, which is a long-read mapper, to align the reads to the human reference genome (hg38). SVs were called by Sniffles detecting all types of SVs. The deletion was found to range from chr14: 23390037 to 23419824 (see figure) and did not contain other SVs. There was no pathogenic SV on ACTC1, GATA4, TBX20 and TLL1 which are genes related to ASD on Genetic Testing Registry.

His mother had also ASD and harbored the same deletion.

Conclusions

This is the first report to identify a large deletion between MYH6 and MYH7 in the family with ASD. The combination of SRS and LRS is useful to detect SVs in patients with suspected inherited diseases but carried no causative SNVs.

Funding Acknowledgement

Type of funding source: None

Systematic Evaluation of KCNQ1 variant using ACMG/AMP Guidelines and Risk Stratification in Long QT Syndrome Type 1

Background

Mutation/variant-site specific risk stratification in long-QT syndrome type 1 (LQT1) has been well investigated, but it is still challenging to adopt current enormous genomic information to clinical aspects caused by each mutation/variant. We assessed a novel variant-specific risk stratification in LQT1 patients.

Methods

We classified a pathogenicity of 142 KCNQ1 variants among 927 LQT1 patients (536 probands and 391 family members) based on the American College of Medical Genetics and Genomics (ACMG) and Association for Molecular Pathology (AMP) guidelines and evaluated whether the ACMG/AMP-based classification was associated with arrhythmic risk in LQT1 patients.

Results

Among 142 KCNQ1 variants, 60 (42.3%), 58 (40.8%), and 24 (16.9%) variants were classified into pathogenic (P), likely pathogenic (LP), and variant of unknown significance (VUS), respectively. The ACMG/AMP guideline-based classification was significantly associated with syncopal events (particularly those during exercise) and LQT risk score (Schwartz score) in overall population. On the other hand, arrhythmic risk was completely different between probands and families even in the same variants. The baseline QTc interval and variant location could stratify the risk in family members but not in probands, however, the ACMG/AMP-based KCNQ1 variant classification stratified the risk in LQT1 probands as well as family members. Multivariate analysis showed that proband (HR=2.52; 95% CI: 1.93–3.30; p<0.0001), longer QTc interval (≥500ms) (HR=1.41; 95% CI: 1.11–1.79; p<0.0001), variants at membrane spanning (MS) (vs. those at N/C terminus) (HR=1.40; 95% CI: 1.07–1.85; p=0.02), C-loop (vs. N/C terminus) (HR=1.58; 95% CI: 1.11–2.24; p=0.01), and P variants [(vs. LP) (HR=1.71; 95% CI: 1.33–2.23; p<0.0001), (vs. VUS) (HR=1.96; 95% CI: 1.19–3.46; p=0.007)] were significantly associated with syncopal events. A clinical score (0–4) based on the proband, QTc (≥500ms), variant location (MS or C-loop) and P variant by the ACMG/AMP guidelines allowed identification of patients more likely to have arrhythmic events (Figure A and B).

Conclusion

Comprehensive evaluation of clinical findings and pathogenicity of KCNQ1 variants based on the ACMG/AMP-based evaluation may stratify arrhythmic risk of congenital long-QT syndrome type 1.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Health Science Research Grant from the Ministry of Health,Labor and Welfare of Japan for Clinical Research on Measures for Intractable Diseases (H24-033, H26-040, H27-032) and a research grant from the Japan Agency for Medical Research and Development (AMED) (15km0305015h0101, 16ek0210073h0001)

Splice site mutation of LMNA causes severe dilated cardiomyopathy via strong dominant reduction of total lamin expression

Objective

LMNA is a known causative gene of dilated cardiomyopathy (DCM) and familial cardiac conduction disturbance (CCD). Genetic variants affecting the pre-mRNA splicing process often lead to premature stop codons and result in nonsense-mediated mRNA decay (NMD), followed by degradation of mutated alleles. The misssense variant LMNA c. 936G>C was previously reported in a French family affected by muscular dystrophy, CCD, and DCM, but no detailed analysis has been performed. We so far identified the same variant in two Japanese families affected by CCD and DCM. In this study, we investigated the molecular consequences of the variant located at the last codon of LMNA exon5 to demonstrate its pathogenicity.

Methods

Genomic DNA and total RNA were isolated from patients' peripheral blood lymphocytes or cardiac tissue. LMNA-coding exons were screened by direct sequencing. Complementary DNAs (cDNAs) were generated by reverse transcription PCR from RNA. Quantitative PCR (qPCR) was performed to quantify the LMNA cDNA amount by using specific primers for lamins A and C. The protein expressions of both isoforms were analyzed by western blotting.

Results

We detected the heterozygous LMNA c.936 G>C (p. Q312H) variant at the end of exon 5 by genomic DNA sequencing in two unrelated Japanese families (figure. pedigree) affected by DCM and CCD. In a genomic database survey, we did not find the variant in either gnomAD, TogoVar, or the Human Genetic Variation Database. The two commonly used splice site predictor tools, NetGene2 and FSPLICE, estimated that this site was a splice donor site. Sequencing of cDNA demonstrated that the mutated allele was absent. By qPCR assay, we confirmed a 90% reduction in LMNA cDNA. Western blot analysis revealed that lamin A and C expression was reduced far more than 50% (figure. western blot).

Conclusions

We report a LMNA missense mutation found in two families, which disrupts a normal splicing site, leads to NMD, and resulted in severe cardiac laminopathy. The drastic reductions of lamin expression at the cDNA and protein levels suggested that other co-existing mechanisms may also have suppressed the expression of the healthy wild type allele.

Pedigree and western blot assay

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Japan Society for the Promotion of Science KAKENHI

Usefulness of collaboration between mathematical models and cell engineering for elucidating complex disease mechanisms and discover effective drugs

Background

A missense mutation, CACNA1C-E1115K, located in the cardiac L-type calcium channel (LTCC), was recently reported to be associated with diverse arrhythmias. Several studies reported in-vivo and in-vitro modeling of this mutation, but actual mechanism and target drug of this disease has not been clarified due to its complex ion-mechanisms.

Objective

To reveal the mechanism of this diverse arrhythmogenic phenotype using combination of in-vitro and in-silico model.

Methods and results

Cell-Engineering Phase: We generated human induced pluripotent stem cell (hiPSC) from a patient carrying heterozygous CACNA1C-E1115K and differentiated into cardiomyocytes. Spontaneous APs were recorded from spontaneously beating single cardiomyocytes by using the perforated patch-clamp technique.

Mathematical-Modeling Phase: We newly developed ICaL-mutation mathematical model, fitted into experimental data, including its impaired ion selectivity. Furthermore, we installed this mathematical model into hiPSC-CM simulation model.

Collaboration Phase: Mutant in-silico model showed APD prolongation and frequent early afterdepolarization (EAD), which are same as in-vitro model. In-silico model revealed this EAD was mostly related to robust late-mode of sodium current occurred by Na+ overload and suggested that mexiletine is capable of reducing arrhythmia. Afterward, we applicated mexiletine onto hiPSC-CMs mutant model and found mexiletine suppress EADs.

Conclusions

Precise in-silico disease model can elucidate complicated ion currents and contribute predicting result of drug-testing.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists

P2865Mutation specific clinical characteristics in long QT syndrome type 8; severe phenotype in Timothy syndrome patients

Background

Long QT syndrome type 8 (LQT8) caused by mutations in CACNA1C has been classified as a very rare and severe type of long QT syndrome accompanied with Timothy syndrome (TS) with extra-cardiac phenotype. Recently, various mutations in CACNA1C have been identified in non-TS patients. However, mutation specific severity in LQT8 has not been elucidated yet, especially for non-TS patients.

Purpose

We aimed to clarify the clinical characteristics of LQT8 patients.

Methods

The study consists of 26 LQT8 patients (21 probands and 5 family members). We evaluated their phenotype.

Results

Table summarizes the clinical characteristics of LQT8 patients. TS patients diagnosed in younger age than those of non-TS. Four TS and one non-TS patients were diagnosed at the age of 0, though the non-TS patient was a son of a patient and asymptomatic. Nine patients suffered symptoms including 7 with cardiac arrest. We identified three TS mutations; classical p.G406R in two and p.G402S in two, and a new TS mutation, p.412M in one. Four of TS patients were symptomatic and two died suddenly at the age of 4 and 5. In contrast, no one died in non-TS patients. Five non-TS patients suffered symptoms in the age of 4,9,15,54 and 64, and the mutations were p.S643F, p.R858H (2 patients), p.K1518E and p.K1591T.

Characteristics of TS and non-TS patient TS Non-TS P N (male) 5 (2) 21 (9) Age (range) 0 (0–7) 12 (0–64) 0.004 Symptom Syncope 4 5 0.034 CPA 3 4 0.101 ECG characteristics   QT interval 603±40 507±14 0.011   T wave alternans 5 2 <0.001   AV Block 4 1 0.002 Therapy (4 unknown)   Beta-blocker 4 7 0.311   Mexiletine 3 1 0.024   ICD implantation 2 2 0.21

Conclusions

Although TS patients showed severe phenotype, most of the non-TS patients were asymptomatic. The phenotype in LQT8 are diversely different depend on the mutations, especially between patients with TS and non-TS.

P3827Low dose of quinidine is effective to normalize the slow inactivation in mutant Kv4.3 channel identified in an early repolarization syndrome patient

Background

Early repolarization syndrome (ERS) is characterized by J-point elevation in the ECG and ventricular fibrillation (VF). Several mutations in genes encoding cardiac ion channels have been reported as the causes for ERS. For the treatment of ERS, clinical studies have shown that quinidine is effective for the suppression of electrical storm. However, the mechanism or the optimal concentration for quinidine to suppress the electrical storm has not been elucidated yet.

Purpose

The aim of the present study is to clarify pharmacological effect of quinidine on mutant Kv4.3 channel by electrophysiological analysis and to establish theoretically effective treatment for ERS.

Methods

A KCND3 mutation, p.G306A, identified heterozygously in a 12-year-old boy was examined by whole-cell patch-clamp methods using CHO cells. We performed functional analysis of the Kv4.3 channels encoded by KCND3 of wild-type (WT), heterozygous (WT/G306A), or homozygous (G306A) mutants. Pharmacological normalizing effects of quinidine to the WT and mutant channels were investigated by loading test in various concentration. The sensitivity of quinidine was evaluated in terms of the concentration of the clinical course and the loading test.

Results

The patient suffered VF while sleeping or under sedation. Significant J-point elevations in multiple leads were recorded and he was diagnosed as ERS. Quinidine administration in the serum concentration of 1.2 to 3.1 μM was effective to stop his VF storm. Mutant Kv4.3 currents showed significantly slow inactivation time course (Fig 1), which meant that the mutation caused the gain-of-function channel. Quinidine loading to the mutant Kv4.3 normalized the inactivation time course in concentration-dependent manner (Fig 2, 3). In the loading concentration of 1 μM, the peak currents were not changed regardless of the voltage (Fig 4). The optimal serum concentration of quinidine in clinical use as multi-ion-channels blocker is 6 to 15 μM and the concentration was higher than that of the patient to stop the VF storm. The electrophysiological analysis showed that the low dose loading of quinidine was effective to prevent the gain-of function change of mutant Kv4.3 channels.

Electrophysiological analysis

Conclusions

We showed the pharmacological mechanism of quinidine against the mutant Kv4.3 channels identified in an ERS patient. Even the low concentration of quinidine was effective to normalize the slow inactivation, gain-of-function, in mutant Kv4.3 channels. Our data would be helpful to confirm the optimal concentration of quinidine for ERS patients to avoid adverse effect.

P5025Structural insights into catecholaminergic polymorphic ventricular tachycardia-associated RyR2 mutant channels using a three-dimensional in silico model

Background

The cardiac ryanodine receptors (RyR2) are large tetrameric calcium-permeant ion channels found in cardiac muscle sarcoplasmic reticulum, which play an important role in the control of intracellular Ca2+ release and cardiac contraction. Mutations in the RYR2 gene are associated with lethal arrhythmia diseases including catecholaminergic polymorphic ventricular tachycardia (CPVT) resulting from increased diastolic Ca2+ leak from mutant channels. RyR2 is a huge protein that each subunit of tetramer is comprised of 4967 amino acids, which hampers the detailed in vitro analysis of RyR2 mutant channels.

Purpose

We aimed to analyze the structural features of RyR2 mutant channels identified in our cohort with inherited arrhythmias using RyR2 three-dimensional (3D) in silico model to reveal the arrhythmogenic mechanisms.

Methods

A targeted next-generation sequencing panel for inherited arrhythmias was employed for genetic diagnosis of the patients. Then, we mapped the identified mutations on RyR2 3D structural model developed by cryo-EM images (PDB: 5go9, 5goa, Peng Science 2016) and investigated the relationship between the location of the mutations and specific functional sites.

Results

As a result of genetic analysis, we identified 93 RYR2 mutations from 112 probands with CPVT (n=93) or long-QT syndrome (LQTS) (n=19).64 of 93 (69%) RYR2 mutations are located in three “hot-spot” area (N-terminal (residues 77–466), central (2246–2534), and channel (3778–4959) hotspot. RyR2 3D in silico modeling revealed that the mutations are regionally distributed mainly in three parts: N-terminal, periphery, and channel part (Figure A). In N-terminal part (1–642 amino acid), 9 of 13 mutations alter the charges of the amino acids (Figure B). Especially, R169L, R169Q, and G172E are close to the interface between two neighboring subunits (∼20Å). These mutations which change the amino acid charge may cause a complete disruption of the ionic pair network and result in largest structural changes, which facilitates RyR2 channel opening. In periphery part (643–3528aa), 22 of 33 mutations are close to the two predicted binding sites of FKBP12.6, a stabilizer of RyR2 (∼5–40Å, Figure C). The mutations are supposed to disturb the binding affinity to the FKBP12.6 resulting in RyR2 channel instability. In channel part (3613–4968aa), 16 of 40 mutations are located near two interface. (FigureD) 12 mutations are close to the Ca2+ sensor and the other 4 mutations are adjacent to the pore-forming segment. Especially, V4821I is just located on this segment and strongly expected to impair the channel function. Above all, RyR2 3D in silico modeling revealed that 63 of all 93 (68%) identified mutations are supposed to be pathogenic.

Location of RYR2 mutations in 3D model

Conclusion

3D structural model of RyR2 is useful for the investigation of the pathogenic mechanisms of CPVT-related mutations. Further studies are needed to elucidate the relationship between the location of the mutations and clinical phenotypes.

P4654Clinical and electrocardiographic features of restrictive cardiomyopathy in children

Introduction

Restrictive cardiomyopathy (RCM) is a rare myocardial disease with an impaired diastolic function and poor prognosis. The mean survival duration after a diagnosis of RCM is reported to be around 2 years in children and most need heart transplantations.

Purpose

This study aimed to determine the 12-lead electrocardiogram (ECG) diagnostic criteria of RCM based on the initial diagnostic electrocardiogram.

Methods

ECGs in pediatric cardiomyopathy patients were collected from 15 institutes in Japan between 1979 and 2013. We compared the ECG findings, especially of the P wave, in RCM patients between the cardiomyopathy group and healthy children group separately for each gender and the age. The ECGs in the healthy group were obtained from school heart screening in Japan of first-graders, and seventh-graders. Statistical significance was determined as p<0.001.

Results

Among 376 registered cardiomyopathy patients, 63 had hypertrophic cardiomyopathy (HCM) (36%), 91 (24%) dilated cardiomyopathy (DCM), 106 (28%) a left ventricular myocardial noncompaction (LVNCs), 25 (7%) restrictive cardiomyopathy (RCM), 14 (4%) arrhythmogenic right ventricular cardiomyopathy (ARVC), and 5 (1%) other cardiomyopathies. Of the 25 RCM patients (9.9±3.4 years old, F:M=11:14), 36% were discovered during school heart screening. The first onset was an abnormal ECG in 9, symptoms of heart failure in 6, respiratory tract infections in 3, syncope in 1, and 6 with other. Of those patients, 2 (8%) had a family history of RCM, 24 (92%) no family history. A genetic diagnosis was performed in 5 of the 25 cases, and 3 had genetic abnormalities related to RCM. The mean follow-up period was 65±95 months (mean±standard deviation). During follow up, 19 patients (76%) survived, 6 (24%) died, 7 (28%) had heart transplantations, and 3 (12%) were waiting for heart transplantations with a left ventricular assist device.

The P wave was bimodal in lead I or biphasic in lead V1 in 15 patients (93%), and 13 (81%) patients had both variations. We evaluated the duration and amplitude of the first and second component of the P wave as P1 and P2. The number of control and RCM patients (control/RCM), duration of P1+P2, and sum total absolute value of the amplitude of P1+P2 in lead V1 were 8350/5, 90±9/116±10ms, and 72±28/528±278μV in first grade boys, 8423/3, 91±10/120±22ms, and 66±28/326±229μV in first grade girls, 8943/1, 97±1/100ms, and 71±31/328μV in seventh grade boys, and 9183/5, 98±11/112±10ms, and 55±27/315±56μV in seventh grade girls. Although the number of patients in the RCM group was small, sum total absolute value of the amplitude of P1+P2 in lead V1 showed a significant difference in any group.

Conclusion

The ECG in children with RCM exhibits P wave abnormalities in almost all patients. In particular, not the P wave interval but P wave shape in I and V1 and the sum total absolute value of the amplitude of P1+P2 in lead V1 were observed differences.

Abstract P4-08-29: Lymphatic invasion is an independent risk factor in patients with small node-negative luminal breast cancer

[Background]

In patients with node-negative (N0), hormone receptor-positive, human epidermal growth factor receptor (HER2) -negative (luminal) breast cancer, the impact of lymphatic invasion (ly) on the prognosis remains to be clarified.

[Methods]

Among 3,158 patients with primary breast cancers who underwent surgery in our institute from January 2007 to December 2009, we analyzed 1027 N0 luminal invasive breast cancers without preoperative systemic therapy. The luminal breast cancer was defined as hormone receptor-positive (ER of ≥ 10% or PgR of ≥ 10%) and HER2-negative (immunohistochemistry: 0, 1+ or FISH: ratio &lt; 2.0) cancer in the postoperative pathological specimen. ly was defined as positive when cancer cell nests were detected within the lymph duct in the whole specimen. N0 was confirmed pathologically by the sentinel lymph node biopsy in all the patients. The Fisher's exact test was used for comparison between different categories. The distant recurrence rate (DRR) was analyzed using the Kaplan-Meier method and the log-rank test. For multivariate analysis, Cox's regression analysis was performed.

[Results]

The median follow-up period was 103.8 months (range: 5.6-128.8). Recurrence with distant metastasis occurred in 26 patients (2.5%). There were 5 (0.7%) deaths related to breast cancer. ly was detected in 240 patients (23.4%). In the ly-positive group, the tumor size was larger (p = 0.007), and the nuclear grade (NG) was higher (p &lt; 0.001) than in the ly-negative group. Postoperative endocrine therapy (p &lt; 0.001) and postoperative chemotherapy (p &lt; 0.001) were more frequently employed for patients with ly-positive tumor. The univariate analysis showed that ly positivity (p &lt; 0.001), large tumor size (p &lt; 0.001), high NG (p &lt; 0.001), PgR negativity (p = 0.002) and the history of adjuvant chemotherapy (p &lt; 0.001) were associated with high DRR. In the multivariate analysis, large tumor size (p = 0.007) and PgR negativity (p = 0.015) remained significant. Although positive ly had a risk ratio of 2.2, it was not an independent risk factor.When restricted to T1 tumor (n = 899), the aforementioned factors still showed prognostic value in the univariate analysis, among which ly positivity (p = 0.004)remained significant together with PgR negativity (p = 0.047)in themultivariate analysis.The 8-year DRR was very favorable (0.8%) in patients with ly-negative T1N0 tumor while it was modest (6.6%) in patients with ly-positive T1N0 tumor (p &lt; 0.001). Only 1.3% of the patients had received adjuvant chemotherapy in the ly-negative group while 27% of the patients had in the ly-positive group.

[Conclusion]

Lymphatic invasion was associated with higher DRR although it was not independent in the multivariate analysis among patients with N0 luminal breast cancer. When restricted to patients with T1N0 luminal breast cancer, the presence of ly was independently associated with higher risk of distant recurrence. It suggests that the assessment of ly is clinically more relevant when considering treatment options for small luminal breast cancer.

Citation Format: Abe T, Ito Y, Fukada I, Shibayama T, Ono M, Kobayashi T, Kobayashi K, Takahashi S, Horii R, Akiyama F, Iwase T, Ueno T, Ohno S. Lymphatic invasion is an independent risk factor in patients with small node-negative luminal breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-29.

Abstract P5-18-11: Prognostic impact and possible pathogenesis of lymph node metastasis in ductal carcinoma in situof the breast

Background: By definition, ductal carcinoma in situ (DCIS) does not metastasize to the lymph nodes. However, since the introduction of molecular whole-node analysis using the one-step nucleic acid amplification (OSNA) assay for sentinel node (SN) biopsies, the number of DCIS patients with SN metastasis has increased. The clinical management of node-positive DCIS remains controversial because these patients can be treated as different stages based on the pathogenesis: e.g. occult invasive cancer with true nodal metastasis (T1N1) or true DCIS with iatrogenic dissemination of benign or tumor cells into lymph node (TisN0). In this retrospective cohort study, we aimed to elucidate the pathogenesis of nodal metastasis in DCIS and the clinical management of node-positive DCIS.

Patients and Methods: Subjects comprised of 427 patients with a routine postoperative diagnosis of DCIS who underwent SN biopsy using the OSNA assay between 2009 and 2012. The cut-off values of the OSNA assay for negative/positive results and micro/macrometastasis were defined at 250 and 5,000 copies/μL of cytokeratin 19 mRNA, respectively. In the SN-positive patients, all paraffin blocks containing the primary tumor were step-sectioned with 0.5-mm intervals until the tissue was exhausted, and all microscopic slides were examined for detecting occult invasions. Afterwards, the patients were classified into three cohorts based on the SN status and occult invasion: (1) no SN metastasis (TisN0), (2) SN metastasis without occult invasion (TisN1), and (3) SN metastasis with occult invasion (T1N1). Tumor characteristics including risk factors of occult invasions (e.g. large size, comedo-type), prognosis, and SN and non-SN status were compared among the three cohorts. The median follow-up time was 73.6 months.

Results: Of the 427 patients, 408 (95.6%) were SN-negative and 19 (4.4%) were SN-positive. By examining a total of 1,421 step-sectioned slides, 9 of the 19 SN-positive patients had occult invasions in the primary tumors. Overall, 408 (95.6%), 10 (2.3%), and 9 (2.1%) were classified into the TisN0, TisN1, and T1N1 cohorts, respectively. Either of adjuvant endocrine therapy or chemotherapy was given much more in the TisN1 and T1N1 cohorts than in the TisN0 cohort (80.0% and 88.9% vs. 5.4%).Other tumor characteristics were similar among the three cohorts. Although one patients had distant recurrence in the TisN0 cohort, none had locoregional or distant recurrences in the TisN1 and T1N1 cohorts. Regarding the lymph node status in the TisN1 and T1N1 cohorts, median tumor burdens in the SN are 590 and 310 copies/μL, and 2 (20.0%) and 2 (22.2%) patients had additional non-SN metastasis in the axillary dissection materials, respectively.

Conclusions: Tumor characteristics and prognosis were similar among the three cohorts albeit the TisN1 and T1N1 cohorts tended to received adjuvant systemic therapy. Moreover, the SN and non-SN status were similar between the TisN1 and T1N1 cohorts. Therefore, pathogenesis of nodal metastasis in DCIS cannot uniformly be explained, and tumors with different stages may be mixed in the node-positive DCIS. Thus, considering the favorable prognosis of node-positive DCIS, the clinical management should be determined on a case-by-case basis.

Citation Format: Yonekura R, Osako T, Iwase T, Ogiya A, Ueno T, Ohno S, Akiyama F. Prognostic impact and possible pathogenesis of lymph node metastasis in ductal carcinoma in situof the breast [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 P5-18-11.

Abstract P3-03-23: Which factor of metastatic lymph nodes–The number, tumor volume or anatomical location–Is independently prognostic in breast cancer? - A prospective cohort study using molecular whole-node analysis of all removed axillary nodes

Background: Axillary lymph node status is one of the most powerful prognostic factors in breast cancer. However, it remains unknown which factor of metastatic lymph nodes–the number, tumor volume or anatomical location–is independently prognostic. Conventional pathological examinations of lymph nodes have limited ability to accurately measure metastatic tumor volume due to the partial evaluation of nodes. On the other hand, the one-step nucleic acid amplification (OSNA) assay, a novel molecular method, can quantify the tumor volume in a whole node based on cytokeratin 19 (CK19) mRNA copy number. In this prospective cohort studyusing the OSNA whole-node analysis, we aimed to elucidate the independent prognostic factor of lymph node metastasis in breast cancer.

Patients and Methods: The subjects consisted of 307 cN0 patients with invasive breast cancer, who underwent axillary dissection after a metastatic sentinel node (SN) biopsy and whose SNs and non-SNs were all examined using the OSNA whole-node assaybetween 2009 and 2012.The cut-off values of the OSNA assay for negative/positive results and micro/macrometastasis were defined at 250 and 5,000 copies/μL of CK19 mRNA, respectively. The total tumor volume in the SN or non-SN was defined as the sum of CK19 mRNA copy numbers from all samples in the SN or non-SN. The cut-off value for the total tumor volume in the SN was set at 2,810 copies/μL according to our previous study (Osako et al. Br J Cancer 2017). The anatomical location of metastasis was classified into Level I (confined to SN), Level I (spread to non-SN), or Level II/III. Predictive factors for distant disease-free survival (DDFS) were investigated using the univariate log-rank tests and multivariate Cox proportional hazards models.The median follow-up time was 6.1 years (range, 0.2–8.6).

Results: Of the 307 patients, 130 (42.3%) and 177 (57.7%) had the total tumor volume &lt;2,810 and ≥2,810 copies/μL in the SN, respectively. Five-year DDFS was 96.0% in the entire cohort. In the univariate analysis, DDFS was significantly related to the pT classification, grade, hormone receptor status, triple-negative subtype, total tumor volume in the SN and cytotoxic chemotherapy. However, DDFS was not significantly related to the number of metastatic or macrometastatic nodes in the SN, non-SN, or all nodes (i.e. SN + non-SN); the total tumor volume in the non-SN or all nodes; the AJCC pN classification; or the anatomical location of metastasis. In the multivariate analysis, the total tumor volume in the SN (&lt;2810 vs. ≥2810 copies/μL, hazard ratio 5.2, 95% confidence interval 1.2–23.2, P=0.03) and cytotoxic chemotherapy (- vs. +, hazard ratio 0.05, 95% confidence interval 0.02–0.17, P&lt;0.001) remained significant.

Conclusions: The total tumor volume in the SN was the independent prognostic factor of lymph node metastasis in SN-positive invasive breast cancer. Accurate evaluation of metastatic tumor burden in the SN can be important for predicting prognosis and may help to guide the precise therapeutic decision making for breast cancer patients.

Citation Format: Osako T, Iwase T, Ushijima M, Ogiya A, Ueno T, Ohno S, Akiyama F. Which factor of metastatic lymph nodes–The number, tumor volume or anatomical location–Is independently prognostic in breast cancer? - A prospective cohort study using molecular whole-node analysis of all removed axillary nodes [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 P3-03-23.

Abstract P1-08-12: Trends in incidence of bilateral breast cancer: A Population-based comparative study of the United States and Japan

Background: Previous studies demonstrated that the incidence rate of invasive contralateral breast cancer (CBC) was 5% within the first 10 years after the primary breast cancer (BC). However improving long-term breast cancer survivorship and advancements in diagnostic imaging have resulted in an increased detection of bilateral breast cancer (BBC), and trends of bilateral invasive and in situ breast cancer are not well established. The aim of this study was to assess national trends of BBC incidence of the United States (US) and Japan.

Methods: The Surveillance, Epidemiology, and End Results (SEER) database (1973-2014) and the clinical database of Breast Oncology Center of Cancer Institute Hospital in Tokyo, Japan (Ganken) database (1946-2015) were used to identify nSEER=11,771 and nGanken=1,499 women diagnosed with BBC, respectively. BBC was defined as invasive BC and/or ductal or lobular carcinoma in situ diagnosed in both breasts simultaneously or after primary breast cancer diagnosis. BBC was grouped into synchronous or metachronous BBC by the interval between first BC and contralateral BC; synchronous cases were defined as CBC diagnosed at the same time or within an interval of 1 year from primary BC diagnosis whereas metachronous cases were defined as a diagnosis occuring 1 year following the primary BC. We assessed trends of BBC incidence and characteristics of BBC cases between the two countries. To determine temporal trends in the incidence of BBC and proportion of the characteristics, we compared them using the Cochrane-Armitage test for trend.

Results: The rates of BBC have significantly increased in both countries (Table 1, 2) [1975: 2.6%; 2014: 7.5% in SEER (p&lt;0.001), 1946-1980: 3.3%; 2011-2015: 10.7% in Ganken (p&lt;0.001)]. The increase was identified in both synchronous and metachronous BBC. In SEER, 40% of synchronous BBC were found as in situ BC and about 15% of BBC presented as invasive lobular carcinoma. More recently, CBC was more likely to be diagnosed at early stages (in situ and local disease) than in previous years [1975: 65%; 2014: 85% in SEER (p&lt;0.001)]. The interval between first BC and contralateral BC have shortened, and CBC were more likely to be operated simultaneously in both countries [1985: 40%; 2014: 51% in SEER, 1946-1980: 24%; 2011-2015: 74% in Ganken].

[Table 1]Crude rates of BBC in all breast cancer in SEER 19751985199520052014All breast cancer941813618258766016471505BBC and rates (%)249 (2.6%)790(5.8%)1421(5.5%)3336(5.6%)5381(7.5%)Rates of synchronous BC2.1%2.8%2.3%2.6%3.5%Rates of metachronous BC0.5%3.0%3.2%3.0%4.0%BBC: Bilateral breast cancer

[Table 2]Crude rates of BBC in all breast cancer in Ganken 1946-19801981-19851991-19952001-20052011-2015All breast cancer47772162280637915241BBC and rates (%)157(3.3%)110(5.1%)188(6.7%)298(7.9%)559(10.7%)Rates of synchronous BC1.0%1.9%2.0%2.7%4.9%Rates of metachronous BC2.3%3.2%4.7%5.2%5.8%

Conclusion: In the modern era, the number of BBC cases have increased and are more likely to be found at an early stage. Further studies are needed to demonstrate the usefulness of early detection of CBC and to define the best means to tailor therapy for patients with bilateral disease.

Citation Format: Sakai T, Ozkurt E, Desantis S, Wong S, Rosenbaum L, Zheng H, Ohno S, Golshan M. Trends in incidence of bilateral breast cancer: A Population-based comparative study of the United States and Japan [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 P1-08-12.

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 P3-10-16: Predicting pathological complete response by the combination of microRNAs in patients with HER2-positive primary breast cancer who received neoadjuvant combination therapy of trastuzumab, lapatinib and paclitaxel: Results from JBCRG-16 (NeoLath) study

[Background] JBCRG-16 (NeoLath) study is a five-arm study to evaluate the efficacy and safety of lapatinib and trastuzumab (6 weeks) followed by lapatinib and trastuzumab plus weekly paclitaxel (12 weeks) with/without prolongation of anti-HER2 therapy prior to chemotherapy (18 vs. 6 weeks), and with/without endocrine therapy in patients with HER2+ and/or estrogen receptor (ER)+ disease. The primary endpoint was pathological complete response (pCR) rate and pCR rate was 47.9% (Masuda N, et al. Breast Cancer, 2018). It is recently reported that microRNAs (miRNAs) are stably present in serum and potentially useful in the diagnosis and evaluation of treatment of cancer. We performed exploratory analysis of detecting pCR by comprehensive analysis of serum miRNAs.

[Materials and Methods] Serum samples were obtained from study participants who received neoadjuvant systemic therapy with trastuzumab, lapatinib and paclitaxel. Before profiling of miRNAs, the overall serum samples were randomly devided in two sets, namely the training set and the testing set with pCR or non-pCR. Pathological complete response (pCR) was defined as the absence of residual invasive cancer of the resected breast specimen and all sampled regional lymph nodes. Total RNA was extracted from a 300 ul serum sample using 3D-Gene® RNA extraction reagent from a liquid sample kit. A comprehensive quantitative expression analysis of miRNA was performed using the by DNA chip 3D-Gene®, which was designed to detect 2565 miRNA sequences registered in miRBase release 21 (http://www.mirbase.org/). The expression level of miRNAs were normalized by internal control (miR-2861, miR-149-3p and miR-4463). Clinicopathological data was retrieved from trial data.

[Results] A total of 112 samples were obtained. Seventy were used in the training set and others were used in the testing set. Median age was 54 years (range 26-70). Sixty-five (58%) patients were pre-menopausal. ER was positive in 59 patients (52.7%). Fourteen (12.5%) were T1c, 78 (69.6%) were T2 and 20 (17.9%) were T3. Fifty-seven (50.9%) patients were node-positive. Fifty-nine (52.7%) patients achieved pCR. The formula with the combination of three miRNAs (miR-A, miR-B, miR-C) was found to be able to predict pCR. This set had a sensitivity of 62.5%, specificity of 86.7% and accuracy of 71.8% in the testing cohort. Area under curve of receiver operationg characteristic curve was 0.753.

[Conclusion] The combination of three miRNAs has potential to predict pCR in patients who received neoadjuvant combination therapy of trastuzumab, lapatinib and paclitaxel in HER2-positive primary breast cancer. The further analysis of changing expression of miRNAs during neoadjuvant therapy is underway and further results will be presented in the symposium.

Citation Format: Shimomura A, Masuda N, Kawauchi J, Takizawa S, Ichikawa M, Matasuzaki J, Kuroi K, Hara H, Yamamoto N, Inoue K, Suganuma N, Aogi K, Ohno S, Tamura K, Ochiya T, Toi M. Predicting pathological complete response by the combination of microRNAs in patients with HER2-positive primary breast cancer who received neoadjuvant combination therapy of trastuzumab, lapatinib and paclitaxel: Results from JBCRG-16 (NeoLath) study [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 P3-10-16.

Improved Serial Sectioning Techniques for Correlative Light-Electron Microscopy Mapping of Human Langerhans Islets

Combined analysis of immunostaining for various biological molecules coupled with investigations of ultrastructural features of individual cells is a powerful approach for studies of cellular functions in normal and pathological conditions. However, weak antigenicity of tissues fixed by conventional methods poses a problem for immunoassays. This study introduces a method of correlative light and electron microscopy imaging of the same endocrine cells of compact and diffuse islets from human pancreatic tissue specimens. The method utilizes serial sections obtained from Epon-embedded specimens fixed with glutaraldehyde and osmium tetroxide. Double-immunofluorescence staining of thick Epon sections for endocrine hormones (insulin and glucagon) and regenerating islet-derived gene 1 α (REG1α) was performed following the removal of Epoxy resin with sodium ethoxide, antigen retrieval by autoclaving, and de-osmification treatment with hydrogen peroxide. The immunofluorescence images of endocrine cells were superimposed with the electron microscopy images of the same cells obtained from serial ultrathin sections. Immunofluorescence images showed well-preserved secretory granules in endocrine cells, whereas electron microscopy observations demonstrated corresponding secretory granules and intracellular organelles in the same cells. In conclusion, the correlative imaging approach developed by us may be useful for examining ultrastructural features in combination with immunolocalisation of endocrine hormones in the same human pancreatic islets.

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 P3-13-06: Tailored neoadjuvant endocrine and chemo-endocrine therapy for postmenopausal patients with estrogen receptor-positive human epidermal growth factor receptor 2-negative primary breast cancer

Aims We investigated the efficacy and safety of initial neoadjuvant endocrine therapy with exemestane (EXE) alone followed by subsequent tailored treatment with EXE alone for responders or EXE plus oral metronomic cyclophosphamide (CPA) for non-responders.

Methods In this multicenter open-label phase II study, we enrolled postmenopausal patients with primary invasive estrogen receptor (ER)-positive, HER2-negative, stage I–IIIA (T1c–T3 N0–2 M0) breast cancer and Ki67 index ≤ 30%. Patients first received EXE 25mg/day for 12 weeks. Based on clinical response and change in Ki67 index in response to the initial therapy, patients who achieved complete response (CR), partial response (PR) with Ki67 index ≤5% after treatment, or stable disease (SD) with Ki67 index ≤5% both before and after treatment were defined as responders. Non-responders were defined as patients with PR and Ki67 index &gt;5% after treatment, or SD and Ki67 index &gt;5% before or after treatment. For the subsequent 24 weeks, responders continued the EXE monotherapy (continued EXE group), whereas non-responders switched to combination therapy with EXE plus CPA 50mg/day (EXE+CPA group). The primary endpoint was clinical response (CR and PR) at weeks 24 and 36.

Results A total of 59 patients (median age 69 years, range 53–86 years) were enrolled between January 2011 and July 2015. After exclusion of 3 (2 with progressive disease, 1 with an adverse event, AE) who discontinued treatment in the initial 12-week EXE monotherapy period, 56 remained enrolled to receive subsequent treatment. After 8–12 weeks of the initial EXE monotherapy, 14 patients were classified as responders (9 with PR and Ki67 index ≤5% after treatment; 5 with SD and Ki67 index ≤5% before and after treatment), whereas 42 were classified as non-responders (3 with PR and Ki67 index &gt;5% after treatment; 39 with SD and Ki67 index &gt;5% before or after treatment). Clinical response rates at weeks 24 and 36 were 85% (12/14, 95%CI 57.2–98.2%) and 76% (10/13, 95%CI 46.2–95.0%), respectively, in the continued EXE group, and 56% (23/41, 95%CI 39.7–71.5%) and 76% (30/39, 95%CI 60.7–88.9%), respectively, in the EXE+CPA group. At week 36, no significant difference was found in median Ki67 index between the continued EXE and EXE+CPA groups (3.5% and 4.0%, respectively). The proportion of patients with preoperative endocrine prognostic index (PEPI) 0 was also similar between the continued EXE and EXE+CPA groups (21.4% and 23.8%, respectively). The breast-conserving surgery rate was 71.4% and 69.0%, respectively. Grade 3 AEs were elevated liver enzymes (1 patient) in the continued EXE group, and gastritis, hypertriglyceridemia, and bone mineral density loss (1 patient each) in the EXE+CPA group.

Conclusion Switching from EXE monotherapy to EXE+CPA combination therapy based on clinical response and biological response (change in Ki67 index) to initial therapy improved subsequent clinical response in non-responders. Favorable clinical response to EXE alone was maintained in responders. Tailored neoadjuvant endocrine and chemo-endocrine therapy was shown to be effective in postmenopausal ER-positive breast cancer patients. (JBCRG-11CPA; UMIN000004751)

Citation Format: Masuda N, Sato N, Morimoto T, Ueno T, Kanbayashi C, Kaneko K, Yasojima H, Saji S, Sasano H, Morita S, Ohno S, Toi M. Tailored neoadjuvant endocrine and chemo-endocrine therapy for postmenopausal patients with estrogen receptor-positive human epidermal growth factor receptor 2-negative primary 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 P3-13-06.

Abstract P5-21-07: Phase II study of eribulin in combination with pertuzumab plus trastuzumab for human epidermal growth factor receptor 2 (HER2)-positive advanced or metastatic breast cancer

Background: Pertuzumab provided overall and progression-free survival (PFS) benefits in HER2-positive metastatic breast cancer patients (pts) in the CLEOPATRA (Clinical evaluation of docetaxel, pertuzumab and trastuzumab) study. However, few studies have described the efficacy of other drugs in combination with pertuzumab plus trastuzumab. Here, we present a pre-specified analysis of eribulin in combination with pertuzumab plus trastuzumab as first- and second-line therapy for advanced or metastatic breast cancer (AMBC) in a multicenter, open-label phase II study (UMIN000012232, JBCRG-M03).

Methods: HER2-positive AMBC with no or single prior chemotherapy for AMBC were enrolled. All pts were administered trastuzumab and taxane as adjuvant or first-line chemotherapy. Treatment consisted of eribulin 1.4 mg/m2 on days 1 and 8 of a 21-day cycle and trastuzumab (8 mg/kg loading dose, then 6 mg/kg) plus pertuzumab (840 mg/body loading dose, then 420 mg/ body) once every 3 weeks, all administered intravenously. The primary endpoint was PFS, and secondary endpoints included overall response rate (ORR) and safety. PFS was determined using Kaplan–Meier analysis. Tumor response was assessed according to RECIST ver. 1.1.

Results: Fifty pts were enrolled from November 2013 to April 2016. Forty-nine pts were eligible for safety analysis and the full analysis set (FAS) included 46 pts. The median age was 56 years (23–70), and 8 (16%) and 41 (84%) pts were treated in first- and second-line settings, respectively. Eleven pts (23.9%) were de-novo Stage 4, and 35 pts (76.1%) had progressed in metastatic disease after completion of local therapy. Median PFS was 9.3 months (M) (95% confidence interval [CI]: 6.4–12.3). Table 1 shows the efficacy data for each treatment line and includes ORR, complete response rate (CR), partial response rate (PR), stable disease rate (SD), progressive disease rate (PD), not evaluable rate (NE) and PFS in the FAS. The median relative dose intensities of eribulin, trastuzumab, and pertuzumab were 93.3% (77.0%–100%), 100% (96.0%–100%), and 100% (89.7%–100%), respectively, in the FAS. The grade 3/4 adverse events (AE) were neutropenia in 5 pts (10.2%), including 2 pts (4.1%) with febrile neutropenia; hypertension in 3 pts (6.1%), and other AEs in only one patient. The average of the ejection fraction did not decrease significantly. Symptomatic left ventricular systolic dysfunction was not observed.

Conclusion: In pts with HER2-positive AMBC, first- and second-line therapy of eribulin in combination with pertuzumab plus trastuzumab demonstrated substantial antitumor activity with an acceptable safety profile. We are planning a phase III study comparing eribulin with taxanes in combination with pertuzumab plus trastuzumab for the treatment of HER2-positive AMBC.

Efficacy data for each treatment lineTreatment LineTotal (n=46)First line (n=8)Second line (n=38)PFS (95% CI), months9.3 (6.4-12.3)20.8 (2.8-38.7)8.7 (7.2-10.2)ORR (%)28 (60.9)7 (87.5)21 (55.3)CR (%)8 (17.4)3 (37.5)5 (13.2)PR (%)20 (43.5)4 (50.0)16 (42.1)SD (%)11 (23.9)1 (12.5)10 (26.3)PD (%)5 (10.9)05 (13.2)NE (%)2 (4.3)02 (5.3)

Citation Format: Kawaguchi H, Yamashita T, Masuda N, Kitada M, Narui K, Hattori M, Yoshinami T, Matsunami N, Yanagihara K, Kawasoe T, Nagashima T, Bando H, Yano H, Hasegawa Y, Nakamura R, Kashiwaba M, Morita S, Ohno S, Toi M. Phase II study of eribulin in combination with pertuzumab plus trastuzumab for human epidermal growth factor receptor 2 (HER2)-positive advanced or metastatic 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 P5-21-07.

Abstract P2-09-31: Predictive impact of absolute lymphocyte counts for progression-free survival in HER2-positive advanced breast cancer treated with pertuzumab and trastuzumab plus eribulin or nab-paclitaxel

Background: Tumor-infiltrating lymphocytes might be a one of predictive outcome of human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer (ABC) patients (pts) who treated with trastuzumab and pertuzumab (TP) plus docetaxel. Although peripheral blood-based parameter (PBBP) is reported as a prognostic indicator of patients with early breast cancers, utility of PBBP has not been studied in HER2-positive ABC.

Objective:The aim of our study was to determine whether PBBP is significant for predictive efficacy in HER2-positive ABC treated with TP combined with eribulin (ERI) or nab-paclitaxel (Nab-PTX).

Methods: The 51 patients' data from two single arm phase II trials was included in this retrospective-prospective study; ERI + TP (n=30) or Nab-PTX + TP (n=21) registered with UMIN000012375 or UMIN000006838, respectively. We assessed the PBBP in prospectively collected data and investigated their association with progression-free survival (PFS). In consideration of PBBP, we evaluated absolute lymphocyte count (ALC), neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR). The cutoff values of ALC, NLR, and PLR were set at 1000 cells/μL, 2, and 250, respectively.

Results:Median age at baseline was 58 years (range: 31-77). Median number of previous chemotherapy was 3 (range: 1-10). Pts had multiple metastases, 53% with LNs, 35% with bone, 25% with lung, 20% with liver, and 6% with brain. The objective response rate (CR+PR) and clinical benefit rate (CR+PR+ more than 6 month SD) were 37% (n=19) and 59% (n=30), respectively. The median PFS of all pts was 301 days (range: 21-1281). The PFS of pts with ALC-High was significantly better than those of ALC-low (hazard ratio (HR): 2.74, 95% confidence interval (CI): 1.28 to 5.86; p= .0097). Furthermore, improved PFS was obtained in pts with ALC greater than 1500 cells/μL compared with less than 1000 cells/uL (HR: 4.05, 95% CI: 1.60 to 11.6; p= .0029). Significant associations seem to exist irrespective of number of previous chemotherapy. Since we combined different studies for evaluating PBBP, ERI and Nab-PTX were calculated separately. Marginally significant associations between ALC and PFS were obtained both in ERI (HR: 2.18, 95% CI: 0.87 to 5.60; p=.0973) and Nab-PTX (HR: 3.26, 95% CI: 0.80 to 12.4; p=.0939). The PFS of NLR-low pts was significantly better than those of NLR-high (HR: 2.29, 95% CI: 1.01 to 5.90; p= .0477), but this statistical difference was inferior to those of ALC. There was no significant association between PLR and PFS.

Conclusions: Pre-treatment ALC-High was significantly correlated with favorable PFS of pts treated with TP irrespective of combination chemotherapy in HER2-positve ABC. Prolonged PFS of TP combination therapy might be obtained mediating through host systemic onco-immunity. These data obtained here suggest that a usefulness of ALC for selecting pts who might have clinical benefit from TP combination therapy for heavily treated HER2-positve ABC.

Citation Format: Araki K, Ito Y, Fukada I, Kobayashi K, Ohno S, Miyagawa Y, Imamura M, Kira A, Takatsuka Y, Egawa C, Suwa H, Miyoshi Y. Predictive impact of absolute lymphocyte counts for progression-free survival in HER2-positive advanced breast cancer treated with pertuzumab and trastuzumab plus eribulin or nab-paclitaxel [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 P2-09-31.

Efficacy and safety of trastuzumab, lapatinib, and paclitaxel neoadjuvant treatment with or without prolonged exposure to anti-HER2 therapy, and with or without hormone therapy for HER2-positive primary breast cancer: a randomised, five-arm, multicentre, open-label phase II trial

Background

Dual blockade of HER2 promises increased pathological complete response (pCR) rate compared with single blockade in the presence of chemotherapy for HER2-positive (+) primary breast cancer. Many questions remain regarding optimal duration of treatment and combination impact of endocrine therapy for luminal HER2 disease.

Methods

We designed a randomised phase II, five-arm study to evaluate the efficacy and safety of lapatinib and trastuzumab (6 weeks) followed by lapatinib and trastuzumab plus weekly paclitaxel (12 weeks) with/without prolongation of anti-HER2 therapy prior to chemotherapy (18 vs. 6 weeks), and with/without endocrine therapy in patients with HER2+ and/or oestrogen receptor (ER)+ disease. The primary endpoint was comprehensive pCR (CpCR) rate. Among the secondary endpoints, pCR (yT0-isyN0) rate, safety, and clinical response were evaluated.

Results

In total, 215 patients were enrolled; 212 were included in the full analysis set (median age 53.0 years; tumour size = T2, 65%; and tumour spread = N0, 55%). CpCR was achieved in 101 (47.9%) patients and was significantly higher in ER− patients than in ER+ patients (ER− 63.0%, ER+ 36.1%; P = 0.0034). pCR with pN0 was achieved in 42.2% of patients (ER− 57.6%, ER+ 30.3%). No significant difference was observed in pCR rate between prolonged exposure groups and standard groups. Better clinical response outcomes were obtained in the prolongation phase of the anti-HER2 therapy. No surplus was detected in pCR rate by adding endocrine treatment. No major safety concern was recognised by prolonging the anti-HER2 treatment or adding endocrine therapy.

Conclusions

This study confirmed the therapeutic impact of lapatinib, trastuzumab, and paclitaxel therapy for each ER− and ER+ subgroup of HER2+ patients. Development of further strategies and tools is required, particularly for luminal HER2 disease.

Electronic supplementary material

The online version of this article (10.1007/s12282-018-0839-7) contains supplementary material, which is available to authorized users.

Research needs in breast cancer

New research questions emerge as medical needs continue to evolve and as we improve our understanding of cancer biology and treatment of malignancies. Although significant advances have been made in some areas of breast cancer research resulting in improvements in therapies and outcomes over the last few decades, other areas have not benefited to the same degree and we continue to have many gaps in our knowledge. This article summarizes the 12 short and medium-term clinical research needs in breast cancer deemed as priorities in 2016 by a panel of experts, in an attempt to focus and accelerate future research in the most needed areas: (i) de-escalate breast cancer therapies in early breast cancer without sacrificing outcomes; (ii) explore optimal adjuvant treatment durations; (iii) develop better tools and strategies to identify patients with genetic predisposition; (iv) improve care in young patients with breast cancer; (v) develop tools to speed up drug development in biomarker-defined populations; (vi) identify and validate targets that mediate resistance to chemotherapy, endocrine therapy and anti-HER2 therapies; (vii) evaluate the efficacy of local-regional treatments for metastatic disease; (viii) better define the optimal sequence of treatments in the metastatic setting; (ix) evaluate the clinical impact of intra-patient heterogeneity (intra-tumor, inter-tumor and inter-lesion heterogeneity); (x) better understand the biology and identify new targets in triple-negative breast cancer; (xi) better understand immune surveillance in breast cancer and further develop immunotherapies; and (xii) increase survivorship research efforts including supportive care and quality of life.