Generating Minimal Training Sets for Machine Learned Potentials

This Letter presents a novel approach for identifying uncorrelated atomic configurations from extensive datasets with a nonstandard neural network workflow known as random network distillation (RND) for training machine-learned interatomic potentials (MLPs). This method is coupled with a DFT workflow wherein initial data are generated with cheaper classical methods before only the minimal subset is passed to a more computationally expensive ab initio calculation. This benefits training not only by reducing the number of expensive DFT calculations required but also by providing a pathway to the use of more accurate quantum mechanical calculations. The method's efficacy is demonstrated by constructing machine-learned interatomic potentials for the molten salts KCl and NaCl. Our RND method allows accurate models to be fit on minimal datasets, as small as 32 configurations, reducing the required structures by at least 1 order of magnitude compared to alternative methods. This reduction in dataset sizes not only substantially reduces computational overhead for training data generation but also provides a more comprehensive starting point for active-learning procedures.

Collaboration on Machine-Learned Potentials with IPSuite: A Modular Framework for Learning-on-the-Fly

The field of machine learning potentials has experienced a rapid surge in progress, thanks to advances in machine learning theory, algorithms, and hardware capabilities. While the underlying methods are continuously evolving, the infrastructure for their deployment has lagged. The community, due to these rapid developments, frequently finds itself split into groups built around different implementations of machine-learned potentials. In this work, we introduce IPSuite, a Python-driven software package designed to connect different methods and algorithms from the comprehensive field of machine-learned potentials into a single platform while also providing a collaborative infrastructure, helping ensure reproducibility. Furthermore, the data management infrastructure of the IPSuite code enables simple model sharing and deployment in simulations. Currently, IPSuite supports six state-of-the-art machine learning approaches for the fitting of interatomic potentials as well as a variety of methods for the selection of training data, running of ab initio calculations, learning-on-the-fly strategies, model evaluation, and simulation deployment.

An Enhanced Synthetic Cystoscopic Environment for Use in Monocular Depth Estimation

As technology advances and sensing devices improve, it is becoming more and more pertinent to ensure accurate positioning of these devices, especially within the human body. This task remains particularly difficult during manual, minimally invasive surgeries such as cystoscopies where only a monocular, endoscopic camera image is available and driven by hand. Tracking relies on optical localization methods, however, existing classical options do not function well in such a dynamic, non-rigid environment. This work builds on recent works using neural networks to learn a supervised depth estimation from synthetically generated images and, in a second training step, use adversarial training to then apply the network on real images. The improvements made to a synthetic cystoscopic environment are done in such a way to reduce the domain gap between the synthetic images and the real ones. Training with the proposed enhanced environment shows distinct improvements over previously published work when applied to real test images.

P1672Late right heart failure predictors after left ventricular assist device implantation

Background

Right heart failure (RHF) after left ventricular assist device (LVAD) implantation is a significant cause of morbidity and mortality. While multiple predictors of early RHF have been described, information on late RHF is scarce. The aim of this study was to identify predictors of late RHF in LVAD patients.

Methods

A retrospective analysis of all adult patients who underwent HeartWare-VAD implantation for ischemic heart disease or non-ischemic dilated cardiomyopathy in a single centre was performed. Late RHF was defined as RHF requiring hospitalization and medical treatment after 30 days of LVAD implantation.

Results

A total of 16 (10.3%) patients from 156 implantations developed late RHF. Patients developing late RHF were older at time of surgery, 56.7±6.9 vs 49.5±12.5 years; p<0.01. A significantly higher rate of moderate or severe tricuspid regurgitation before implantation was found in patients presenting with late RHF, 81.2% vs 33.5%; p<0.001. Several echocardiographic parameters at discharge post-implant, such as mitral regurgitation, demonstrated a strong association with late RHF. A multivariate Cox proportional-hazards regression analysis (table 1) revealed that significant pre-operative tricuspid regurgitation (moderate or severe) was the strongest predictor of late RHF development after LVAD surgery (HR 5.50, 95% CI [1.34–22.58]; p=0.02). Significant mitral regurgitation post-implantation and older age also predicted late RHF development.

Multivariate Cox proportional-hazards analysis for late right heart failure Variable Hazard ratio 95% confidence interval P-value Tricuspid regurgitation- moderate or severe 5.50 1.34–22.58 0.02 Mitral regurgitation (discharge)- moderate or severe 3.54 1.14–11.02 0.03 Age 1.07 1.01–1.14 0.03 Right ventricular basal diameter 1.14 0.43–3.03 0.79 Right ventricular fractional area change 0.98 0.87–1.10 0.79 Multivariate analysis showing predictors of late right heart failure according to a multivariate model.

Late RHF according to TR severity

Conclusions

Pre-operative significant tricuspid regurgitation and mitral regurgitation after implantation predict the occurrence of late RHF. Prospective studies are needed to determine whether tricuspid valve interventions may reduce late RHF.

P5418Anticoagulation management of heartware left ventricular assist device thrombosis: comparison of heparin and bivalirudin

Introduction and purpose

Pump thrombosis (PT) is a serious left ventricular assist device (LVAD) complication, though there are no guidelines regarding its treatment. We have adopted a strategy of intravenous anticoagulation as the initial treatment strategy in these patients.

Methods

All consecutive patients who received a HeartWare LVAD from July-2009 to January-2018 were retrospectively analyzed. Patients developing a PT were selected, and treatment, outcomes and complications were recorded.

Results

197 patients underwent HVAD, and 49 developed PT. All the patients were initially treated medically, though during the first PT 26.5% of the patients needed surgery [VAD exchange (n=6), transplant (n=6), or decommissioning (n=1)]. The overall survival at 1 year was 63.3%. Patients were treated predominantly with either intravenous heparin or bivalirudin. There were no significant differences neither in complications nor in survival between the 2 treatments (Figure 1); however, patients treated with bivalirudin during the first PT episode had less subsequent re-thrombosis episodes (18.2% vs 57.7%, p<0.05), and percentage time in therapeutic range was greater for bivalirudin compared with heparin (59.7±4.2 vs 36.3±7.1, p<0.01). Nevertheless, time to normalisation of LDH levels with bivalirudin was longer than with heparin (17.2±2.6 vs 10.2±4.5 days, p<0.01) (Table 1).

Table 1. Comparison of baseline characteristics and outcomes between Heparin and Bivalirudin Heparin (n=26) Bivalirudin (n=11) p-value Male, gender n (%) 20 (76.9) 9 (81.8) 1.00 Age when implant (years) 48±11.8 49.8±11.4 0.67 AF n (%) 9 (34.6) 6 (54.5) 0.50 Diagnosis:   Dilated cardiomyopathy n (%) 13 (50) 7 (63.6)   Ischemic heart disease n (%) 12 (46.2) 3 (27.3)   Congenital heart disease n (%) 1 (3.8) 1 (9) 0.50 Thrombolysis (+ alteplase) n (%) 19 (73.1) 4 (36.4) 0.08 Treatment duration (days) 11.5±7.2 15.3±6.5 0.15 % Time in range 36.3±7.1 59.7±4.2 0.009 Hospitalisation (days) 19.1±16.4 31.9±18.2 0.06 Complications:   Ischemic Stroke n (%) 2 (7.7) 4 (36.4) 0.09   Intracraneal bleeding n (%) 2 (7.7) 0 (0) 0.88   Gastrointestinal bleeding n (%) 1 (3.8) 0 (0) 1.00   Serious bleeding n (%) 5 (19.2) 0 (0) 0.29   Any bleeding n (%) 7 (26.9) 2 (18.2) 0.88 LDH   Baseline 271.7±79.3 221.6±41.3 0.10   Admision 727.8±448.2 517.5±171.3 0.21   Maximum 827.1±424.7 1217.6±1004 0.03   Discharge 334.9±135.9 308.6±111.8 0.70   Time to normalisation (days) 10.2±4.5 17.2±2.6 0.004 Outcomes:   Transplant (total) n (%) 7 (26.9) 2 (18.2) 0.88   VAD Exchange (total) n (%) 8 (30.8) 4 (36.4) 1.00   Mortality at 2 years n (%) 15 (57.7) 5 (45.4) 0.831 Rethrombosis:   Rethrombosis n (%) 15 (57.7) 2 (18.2) 0.03   Number of episodes of rethrombosis 0.15     +1 n=6 n=1     +2 n=4 n=1     +3 n=4 n=0     +4 n=1 n=0

Figure 1

Conclusion

VAD thrombosis is a serious life threatening complication, though an initial strategy with enhanced intravenous anticoagulation is an acceptable strategy with either intravenous heparin or bivalirudin.

Acknowledgement/Funding

N. Bouzas-Cruz would like to thank the Spanish Society of Cardiology (Sociedad Española de Cardiología), for her research grant and fellowship.

P1677Elevation of right-sided pressures and right ventricular echocardiographic parameters: predictors of Exercise Limitation in Patients with Implanted Continuous Flow Left Ventricular Assist Devices

Introduction

Left Ventricular Assist Devices (LVAD) improve survival and functional capacity in patients with advanced heart failure (HF). However, there are potential complications.

Purpose

We sought to determine parameters of exercise intolerance in a group of patients with the HeartWare LVAD (HVAD) compared to a group of HF patients.

Methods

This was a single-centre parallel prospective group-study. Briefly, echocardiograms, right heart catheterisation (RHC) and cardiopulmonary exercise tests were performed in forty-two patients admitted for a heart transplant assessment between August2017 and October2018.Of them 20 belonged to the HVAD group and 22 to the HF group.

Results

In our study, HVAD patients had a better exercise capacity than HF patients, although no significant differences were noted (14.0±5.0 ml/kg/min vs 11.3±3.9 ml/kg/min, p=0.06). To determine exercise tolerance, both HVAD and HF groups were subdivided into 2 groups based on the median peak exercise oxygen consumption (peakVO2) for that group. The table shows the comparison between preserved and non-preserved exercise tolerance in HF and HVADpatients. First of all, in the HVADgroup, all resting RHC pressures were significantly lower in the preserved exercise capacity group. However, in HFpatients there were no statistically significant differences between both subgroups in right-sided pressures, but Thermodilution exercise-induced change in cardiac output (ΔCO) and cardiac index (ΔCI) was significantly higher in the patients with preserved exercise tolerance. Secondly, in the HVADgroup the right ventricle was significantly larger in the reduced exercise tolerance subgroup. Moreover, patients with lower peak VO2 had more significant tricuspid regurgitation. Nevertheless, in HFpatients none of the echocardiographic parameters were related to the exercise capacity.

HF HVAD > Median Peak V02 < Median Peak V02 p > Median Peak V02 < Median Peak V02 p Thermodilution CO, l/min: • Rest 4.3±1.0 4.4±1.8 0.82 4.8±0.8 4.2±1.2 0.21 • Exercise 5.6±1.7 4.8±1.8 0.36 7.1±3.2 4.8±0.8 0.05 • ΔCO 1.26±1.0 0.26±0.7 0.02 2.2±2.5 0.4±0.7 0.05 Right Atrium pressure, mmHg 7.0±4.5 6.8±4.10 0.92 4.3±3.2 10.6±6.40 0.02 Mean Pulmonary Artery pressure, mmHg 26.4±12.6 26.5±10.9 0.97 16.8±5.4 30.5±12.5 0.01 Tricuspid Regurgitation, n (%): • None 1 (9) 1 (9) 1 (12) 0 (0) • Mild 7 (64) 8 (73) 7 (88) 4 (44) • Moderate 2 (18) 0 (0) 0 (0) 4 (44) • Severe 1 (9) 2 (18) 0.36 0 (0) 1 (12) 0.03 Right Ventricle Basal Diastolic Diameter, cm 4.0±1.0 4.1±1.0 0.83 3.7±0.5 4.4±0.5 0.02

Conclusion

Right-sided parameters in the echocardiogram and RHC pressures discriminate between preserved and non-preserved exercise capacity in HVADpatients, but not in HFpatients. In these last patients only ΔCO and ΔCI were statistically correlated with peak exercise oxygen consumption

Acknowledgement/Funding

N. Bouzas-Cruz would like to thank the Spanish Society of Cardiology (Sociedad Española de Cardiología), for her research grant and fellowship

Abstract P4-13-01: Oncoplastic breast conservations – The Scottish Audit: Surgical techniques, oncological outcomes, complication rates and variations in practice across the country based on the analysis of 589 patients

Introduction: current evidence for oncoplastic breast conservation (OBC) is based on single institutional series. We studied the outcomes of OBC practice in Scotland and compare individual breast units.

Methods: a predefined database of patients treated with OBC was completed retrospectively in 11 breast units in Scotland. Patients were treated with OBC from 2005 onwards were included. For statistical calculations Chi-test, ANOVA and Pearson correlation analysis were used.

Results: Altogether 589 patients were included. Median age was 56 years [21-86]. Patients were diagnosed between September 2005 and March 2017. Number of patients treated with OBC per unit ranged between 4 and 145. High volume units were doing a mean of 19.3 OBCs per year [17.3 – 26.5] vs. low volume units doing 11.1 OBCs per year [7 .7– 14.4] (p=0.012).

23 different oncoplastic surgical techniques were applied. Range of oncoplastic techniques used was associated with case-loads: high volume units used a wider range (8 – 14 different techniques) compared to low volume units (3 – 6) (p=0.004). Volume displacement was done in 515 patients (91.3%), volume replacement in 49 patients (8.7%). OBC was carried out as a joint operation between a breast and a plastic surgeon in 66.3% (389 patients). Immediate contralateral symmetrisation rate was significantly higher when the procedure was carried out as a joint operation (70.7% vs. not joint operations: 29.8%; p&lt;0.001).

Incomplete excision rate was 10.4% (60 of 578). Incomplete excision was significantly higher after invasive lobular carcinoma (18.9%; 10 of 43; p=0.0292). After neoadjuvant chemotherapy incomplete excision rate was significantly lower (3%; 2 of 66 vs. no neoadjuvant chemotherapy: 11%; 35 of 319; p=0.031).

Neodjuvant systemic treatment rate was 28.6% (142 of 496 patients). Of those 68 patients received neoadjuvant chemotherapy (13.7%) and 74 patients had neoadjuvant hormonal treatment (14.9%). Neoadjuvant systemic treatment rate varied amongst the units from 9.7% to 57.2% for patients with invasive carcinoma.

259 patients diagnosed with (non)invasive carcinoma had a median follow-up time of 5 years [35-124]. Of these 7 patients (2.7%) developed isolated local recurrence. 5-year local recurrence rate after DCIS was higher than after pure invasive ductal carcinoma (DCIS: 8.3%; 3 of 36 vs. ductal: 1.6%; 3 of 181; p=0.02567). 5-year disease-free survival of these patients was 91.7%, overall survival was 93.8%, and cancer-specific survival was 96.1%.

145 of 510 patients developed complications, which is 28.4% overall complication rate. 71 patients had major complications (13.9%) and 74 patients had minor complications (14.5%). Overall complication rate was significantly lower after neoadjuvant chemotherapy (15.9%; 11 of 69) compared to patients who did not receive neoadjuvant chemotherapy (27.9%; 127 of 455 patients) (p=0.035).

Conclusion: this national audit demonstrated similar outcomes overall compared to relevant published data. Units should be urged to build stronger collaboration in order to reduce variability in OBC practices.

None of the authors have conflict of interest to declare.

Citation Format: Romics L, Macaskill J, Fernandez T, Morrow E, Simpson L, Pitsinis V, Barber M, Tovey S, Masannat Y, Young O, Mansell J, Stallard S, Doughty J, Dixon M. Oncoplastic breast conservations – The Scottish Audit: Surgical techniques, oncological outcomes, complication rates and variations in practice across the country based on the analysis of 589 patients [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 P4-13-01.

Physical Activity Levels of Women Attending Glasgow Breast Clinics

IntroductionEpidemiological studies suggest that moderate intensity recreational physical activity (PA) improves breast cancer survival. We aimed to assess the current levels of PA in breast cancer survivors and a cohort of women with benign disease attending clinics in Glasgow.Materials and MethodsPatients at breast clinics at the GRI and WIG were recruited over a 5 week period. Data on physical activity levels (occupational, household, recreational) over the 7 days were recorded using the International Physical Activity Questionaire (IPAQ).ResultsA total of 352 patients were recruited with 141 (40.1%) of the patients completing the questionnaire successfully (table 1).Table 1  Women attending symptomatic clinicBreast cancer survivorsNo. patients 9742Median Age 4263Average physical activity levels (MET-Hr / Week)Total11493.4 Physical19.619.7 Household35.740.0 Occupational40.523.9 Recreational PA appears to be the major influence on breast cancer survival (1) and the reported MET-hr/week for each cohort are shown in table 2.Table 2Recreational Physical activity levels (MET-Hr / Week)Women attending symptomatic clinicBreast cancer survivors&lt;533 (34%)21 (50%)5 - 1014 (14%)5 (12%)10 - 1918 (19%)8 (19%)&gt;1932 (33%)8 (19%) DiscussionScottish guidelines (2) suggest 30min of moderate exercise most days a week is beneficial (&gt;10MET-hr/week) but over 60% of our patients were not achieving this. A recreational PA level of &gt;5MET/hr/week has been demonstrated to confer a benefit on breast survival (1). However 50% of our breast cancer survivors are not meeting this relatively modest target (equivalent to 1hr15min moderate activity/week). With the planned implementation of an exercise programme for all newly diagnosed breast cancer patients in Glasgow, we hope to improve levels of recreational physical activity and will re-audit following its introduction.References1. Friedenreich CM, Gregory J, Prospective cohort study of lifetime physical activity and breast cancer survival. Int J Cancer. 2009 Apr 15;124(8):1954-622. Let's Make Scotland more active: A strategy for physical activity. Physical activity task force http://www.scotland.gov.uk/Publications/2003/02/16324/17895 [Online March 2009]

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2066.

Poor Survival Outcomes in Elderly HER2 Positive Breast Cancer Patients

IntroductionIncreasing age is a major risk factor for breast cancer. The majority of breast cancers in Europe and USA are in women over 65 and with an aging population this will become an increasing concern. Despite this, there are suggestions of bias in allocating treatment based on chronological rather than physiological age, with adverse effects on survival (1). In addition, women over 70 are usually excluded from randomised clinical trials. One particular area of controversy is the treatment of HER2 positive elderly women with trastuzumab +/- concurrent chemotherapy, particularly with the concerns over cardiac toxicity in these patients.MethodsWe analysed a cohort of 255 patients older than 70 years to assess the impact of HER2 positivity (IHC Herceptest 3+ or FISH positive) on survival in elderly women with breast cancer. These patients were selected from a database of 1400 breast cancers diagnosed between 1980-2002 which contains all clinicopathological details and full follow-up (median 5.3yrs). The group were 81% ER positive, 74% grade I or II, and 49% node positive. Only 2.7% received chemotherapy but 82% received endocrine therapy (tamoxifen).SPSS version 12 was used to calculate univariate Kaplan Meier Survival Curves and multivariate cox regression analysis using breast cancer specific death as an endpoint.ResultsThe HER2 positivity rate was 5.9% which is substantially lower than the 11.9% positive in the original unselected database of 1400 patients.HER2 positive elderly patients (n=15) had significantly poorer breast cancer specific survival rates of 65% compared to 79% at 5 years for the HER2 negative group (p=0.036). In cox regression analysis along side known prognostic variables of grade, size, nodal and ER status the hazard ratio for HER2 positivity was 2.58 (95% CI 1.079-6.147, p&lt;0.033).ConclusionAs previously reported, our cohort of elderly women have low rates of HER2 positive disease, however HER2 status remains a significant predictor of breast cancer specific survival outcome. Whilst no adjuvant trastuzumab trials have directly targeted this age group (with minimal inclusion of patients &gt;70 in any trial), we know that cardiac toxicity increases with age and with anthracycline use (2). This however is generally reversible and treatment certainly should be considered if there is adequate cardiac function. A clinical trial to assess the benefit of adjuvant trastuzumab alone (with endocrine therapy) in this group of patients is suggested in this largely ER positive cohort. The role of the dual inhibitor lapatinib should also be explored with suggestions of less cardiotoxicity with this agent (2).Reference List1. Eaker S, Dickman PW, Bergkvist L, Holmberg L 2006 Differences in management of older women influence breast cancer survival: results from a population-based database in Sweden. PLoS Med 3:e252. Perez EA 2008 Cardiac toxicity of ErbB2-targeted therapies: what do we know? Clin Breast Cancer 8 Suppl 3:S114-S120

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2010.

The Role of the Systemic Inflammatory Response in Long Term Outcome from Operable Breast Cancer

Aims: It is recognised that the presence of a systemic inflammatory response has independent prognostic value in a number of advanced and operable tumours. There is also evidence in advanced breast cancer (Al Murri et al., 2006). However, results in operable breast cancer have been conflicting. Therefore, we prospectively examined the relationship between the systemic inflammatory response and long term survival in primary operable breast cancer.Methods: Patients with invasive primary operable breast cancer (n=154) treated at Royal and Western Infirmaries, Glasgow between October 2000- January 2002 were studied. The systemic inflammatory response, as evidenced by elevated CRP and Il-6, was measured pre-operatively and approximately 12 months later. An elevated CRP was defined as &gt;10mg/l, and IL-6 as &gt;5ng/l. Demographic and clinical data including age, tumour size, histological grade, lymph node status oestrogen receptor (ER) status and HER2 status were recorded. The Nottingham prognostic index (NPI) was calculated and subdivided into good (0-3.4), intermediate (3.41-5.4) and poor (&gt;5.41) prognosis. Patients were followed-up until 1st March 2009.Results: Mean age was 59 (range 34-87). HER-2 was positive in 18 patients (12%), ER status was positive in 121 patients (79%). NPI was good/ intermediate/poor in 55 (36%)/ 73 (47%)/ 26 (17%). Circulating concentrations of interleukin-6 were significantly correlated with those of C-reactive protein (rs=0.449, p&lt;0.001). Median follow-up was 8 years (range 7 – 8.5 years). During this period, there were 20 breast cancer deaths and 16 of other causes. On univariate analysis, NPI (p&lt;0.001), pre-operative CRP (p=0.03), pre-operative IL-6 (p=0.05) and post-operative CRP (p=0.05) predicted breast cancer specific survival. In contrast, post-operative IL-6, ER and HER2 status did not. On multivariate analysis, NPI (HR 7.78 95% CI: 3.44-17.61 p&lt;0.001) and pre-operative CRP (HR 6.36 95% CI: 2.11-19.18, p=0.001) predicted breast cancer specific survival.Conclusions: The results of the present study suggest that the presence of a systemic inflammatory response prior to surgery, in particular CRP, predicts breast cancer specific survival independent of tumour based factors. Therefore measurement of the systemic inflammatory response may be useful in the pre-operative assessment of patients with primary operable breast cancer.We acknowledge the advice and support of Timothy G Cooke who died 20th July 2008.ReferenceAl Murri AM, Bartlett JM, Canney PA, Doughty JC, Wilson C, McMillan DC. Evaluation of an inflammation-based prognostic score (GPS) in patients with metastatic breast cancer. Br J Cancer. 2006;94:227-30.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4050.

The relationship between tumour NF-kB expression, hormone status and survival in primary invasive breast cancer

Abstract #4041

Breast cancer is one of the most common and lethal malignancies in the UK. Conventionally, prognosis is based on hormone status, tumours size, grade and lymph node involvement. We have recently observed that NF-kB expression and activation was associated with progesterone receptor (PR) expression irrespective of oestrogen receptor (ER) status in primary invasive breast cancer (Tannahill et al., unpublished observations). The aim of the present study was to examine the relationship between NF-kB, PR and survival in a selected cohort of ER positive tamoxifen treated primary invasive breast cancer.&#x2028; Immunohistochemistry was performed on 372 breast tumours, with full clinicopathological characteristics. Antibodies were directed total NF-kB and NF-kB phosphorylated at serine 536 (phospho NF-kB). Two observers independently scored expression using the weighted histoscore technique, and grouped expression as tertiles. There was a minimum follow-up period of 4.9 years and a median follow-up of 6.8 years. During follow-up 104 patients died, 65 of which died of their disease, 96 patients recurred, 70 of which was while on tamoxifen.&#x2028; Nuclear NF-kB, either total or phosphorylated, expression was not associated with recurrence or survival. However, when the cohort was subdivided into PR positive (n=220) and PR negative tumours (n=140), increased nuclear phospho NF-kB expression was associated with increased recurrence (p&lt;0.05) and increased recurrence on tamoxifen therapy (p&lt;0.05) in PR positive tumours. In contrast, increased nuclear phospho NF-kB expression was associated with decreased recurrence (p&lt;0.05) and decreased recurrence on tamoxifen therapy (p&lt;0.05) in PR negative tumours.&#x2028; The results of the present study suggest that the effect of nuclear expression of phospho NF-kb on outcome in ER positive primary invasive breast cancer is dependent on PR status. The study highlights the importance of patient selection for the evaluation of the use of NF-kb inhibitors in patients with breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4041.

Role of extracellular signal-regulated kinase 5 (ERK5) in human breast cancer

Abstract #4042

Background&#x2028; ERK5 is a novel member of the mitogen-activated protein kinase (MAPK) family. MAPKs regulate multiple cellular functions, including proliferation, differentiation and survival. Recent studies have implicated the ERK5 pathway in human breast cancer. As breast cancer is now the most common type of cancer in the UK, research into this potential biomarker is essential.&#x2028; Method&#x2028; An optimised immunohistochemistry protocol (McCracken S. Oncogene 2008) was applied to examine expression of ERK5 in a cohort of 10 normal breast samples and 402 estrogen receptor (ER) positive breast cancer specimens from patients treated with Tamoxifen. ERK immunoreactivity was quantified using a weighted histoscore method (Kirkegaard T. Histopathology 2006), and the data was corroborated to clinico-pathologic parameters including the HER family (Tovey S. Clin Can Res. 2005).&#x2028; Results&#x2028; Of 402 tumours on the TMA, 346 cases were informative. Follow-up was available for a minimum of 10 years: 239 with stable disease, 94 cases recurred (13 with bilateral recurrence) and 84 received adjuvant chemotherapy.&#x2028; ERK5 expression in the tumour cohort was observed in the cytoplasm with 78% of samples having weak staining with a histoscore of &lt;100, 20% with moderate staining with a score between 100-200 and 2% with strong staining, histoscore&gt;200. ERK5 expression in the nucleus demonstrated 85% of cores with a histoscore &lt;100 (weak) and 15% between 100-200 (moderate). Almost all ERK5 membrane staining was weak (99% had a histoscore of &lt;100). ERK5 cytoplasmic and nuclear expression were directly associated (c.c.=0.682, p&lt;0.001) and ERK5 nuclear expression showed a trend for association with tumour size (p=0.069). In addition, ERK5 cytoplasmic expression was weakly associated with HER1-3 positivity (p=0.022) and nodal status (p=0.039). Interestingly, both cytoplasmic and nuclear ERK5 expression correlated with cytoplasmic and nuclear ERK1/2 expression (p=0.001 and p=0.003, respectively).&#x2028; All of the benign breast cases expressed cytoplasmic ERK5 at a relatively weak level (100% with a histoscore&lt;100). Again cytoplasmic and nuclear expression in the benign cohort correlated (c.c. =0.879 and p=0.001). Benign and tumour breast tissue expressed significantly different levels of nuclear ERK5 (p=0.002).&#x2028; Discussion &#x2028; This study demonstrates that ERK5 is commonly expressed in breast cancer specimens. ERK5 nuclear expression was shown to be related to tumour size, suggesting a potential role in proliferation. In support of this observation ERK5 expression also strongly correlated with expression of ERK1/2 in this cohort. ERK5 was also shown to be associated with nodal status and HER1-3 expression. Therefore our data supports the need for further investigation into the role of ERK5 in breast cancer, including ER negative patients.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4042.

Phosphorylated c-Src in the nucleus is associated with improved patient outcome in ER-positive breast cancer

Elevated c-Src protein expression has been shown in breast cancer and in vitro evidence suggests a role in endocrine resistance. To investigate whether c-Src is involved in endocrine resistance, we examined the expression of both total and activated c-Src in human breast cancer specimens from a cohort of oestrogen receptor (ER)-positive tamoxifen-treated breast cancer patients. Tissue microarray technology was employed to analyse 262 tumour specimens taken before tamoxifen treatment. Immunohistochemistry using total c-Src and activated c-Src antibodies was performed. Kaplan–Meier survival curves were constructed and log-rank test were performed. High level of nuclear activated Src was significantly associated with improved overall survival (P=0.047) and lower recurrence rates on tamoxifen (P=0.02). Improved patient outcome was only seen with activated Src in the nucleus. Nuclear activated Src expression was significantly associated with node-negative disease and a lower NPI (P<0.05). On subgroup analysis, only ER-positive/progesterone receptor (PgR)-positive tumours were associated with improved survival (P=0.004). This shows that c-Src activity is increased in breast cancer and that activated Src within the nucleus of ER-positive tumours predicts an improved outcome. In ER/PgR-positive disease, activated Src kinase does not appear to be involved in de novo endocrine resistance. Further study is required in ER-negative breast cancer as this may represent a cohort in which it is associated with poor outcome.

202. Differential dietary regulation of placental and muscle myostatin in a transgenerational rat model of maternal under-nutrition

Myostatin, a negative regulator of muscle growth, affects glucose uptake independent of insulin and also regulates placental glucose uptake in vitro in the human placenta. Maternal under-nutrition during early gestation has been associated with fetal programming for increased risk of metabolic disorders in later life. The aim of this project was to investigate changes in myostatin expression in placental and muscle samples in an established rat model of fetal programming. Pregnant rats were fed either a standard diet ad libitum (AD) or 30% of ad libitum (UN) throughout gestation. Female F1 offspring were in turn subjected to AD or UN conditions throughout pregnancy, giving three groups of F2 offspring: AD-AD, AD-UN and UN-AD. The F2 rats were then fed either a chow or a high fat (HF, 65% kcals fat) diet. Muscle and placental samples were collected at various time-points for analysis of myostatin and pro-myostatin expression. Myostatin mRNA expression was found to be significantly higher in placentae compared with skeletal muscle samples, and in UN-AD muscle compared with AD-AD muscle. At the protein level, expression of both myostatin dimer and precursor varied with time and across groups: particularly, placental myostatin dimer expression was significantly higher in UNAD females compared with ADUN and ADAD groups; muscle myostatin precursor expression was reduced in AD-UN and UN-AD females compared with the AD-AD group at embryonic day20; while at day140, there was a trend towards an increase in muscle myostatin dimer expression in UN-AD HF fed compared with UN-AD CHOW animals. Our data demonstrate that in response to maternal diet myostatin is differentially regulated in placentae compared with skeletal muscle, with both myostatin dimer and myostatin precursor levels affected. Modulation of placental myostatin activity through changes in relative expression of myostatin dimer and myostatin precursor in response to maternal diet may contribute to aberrant nutritional uptake by the fetus.

Observer variation in immunohistochemical analysis of protein expression, time for a change?

AIM

Immunohistochemical analysis of protein expression is central to most clinical translational studies and defines patient treatment or selection criteria for novel drugs. Interobserver variation is rarely analysed despite recognition that this is a key area of potential inaccuracy. Therefore our aim was to examine observer variation and suggest the revision of current standards.

METHODS AND RESULTS

We analysed inter- and intra-observer variation, by interclass correlation coefficient (ICCC) and kappa statistics, in 8661 samples. Intra-observer assessment of nuclear, cytoplasmic and membrane staining for seven proteins in 1323 samples resulted in an ICCC of 0.94 and a kappa-value of 0.787. Interobserver reproducibility, assessed on 28 proteins by seven observer pairs in 8661 carcinomas, gave an ICCC of 0.90 and a kappa-value of 0.70. No significant effect of either antibody or cellular compartmentalization was observed.

CONCLUSION

We have demonstrated that ICCC is a consistent method to assess observer variation when a continuous scoring system is used, compared with kappa statistics, which depends on a categorical system. Given the importance of accurate assessment of protein expression in diagnostic and experimental medicine, we suggest raising thresholds for observer variation: ICCC of 0.7 should be regarded as the minimum acceptable standard, ICCC of 0.8 as good and ICCC of > or = 0.9 as excellent.

Inhibition of the cerebellar inositol 1,4,5-trisphosphate-sensitive Ca2+ channel by ethanol and other aliphatic alcohols

The effects of ethanol and other aliphatic alcohols on the endoplasmic reticulum Ca2+ pump and the inositol 1,4,5-trisphosphate (InsP3)-sensitive Ca2+ channel were studied in pig cerebellar microsomes. Methanol, ethanol and propanol all stimulated ATP-dependent Ca2+ uptake, whereas butanol inhibited this process. Ethanol inhibited InsP3-induced Ca2+ release [half-maximal inhibition at 3.5%, v/v (600 mM)]. However, ethanol affected only the amount of InsP3-releasable Ca2+, without affecting the concentration of InsP3 required to induce half-maximal release. Other alcohols of longer chain length were more potent than ethanol at inhibiting InsP3-induced Ca2+ release, but none of the alcohols tested affected [3H]InsP3 binding to its receptor. Using stopped-flow techniques, measurements of the rate of InsP3-induced Ca2+ release in the preparation of pig cerebellar microsomes used in this study showed the kinetics to be monophasic, with a rate constant of 0.93s-1 at 20 microM InsP3. This rate constant was dependent upon InsP3 concentration, decreasing to 0.38s-1 at 0.25 microM InsP3. Ethanol was shown to reduce the fractional amount of InsP3-induced Ca2+ release without significantly affecting the rate constant for this process.

Pharmacological modulators of the inositol 1,4,5-trisphosphate receptor

Elevation of cytosolic calcium concentrations, induced by many neurotransmitters, plays a crucial role in neuronal function. Some neurotransmitters produce the second messenger InsP3 which activates an intracellular calcium channel (InsP3 receptor) usually located in the endoplasmic reticulum. This article undertakes a comprehensive survey of most pharmacological modulators of the InsP3 receptor so far reported. This review discusses in detail competitive antagonists, non-competitive antagonists and thiol reactive reagents, highlighting their modes of action and in some cases indicating drawbacks in their use.

Clinical and bronchoscopic diagnosis of suspected pneumonia related to AIDS

In a series of 25 patients with suspected pneumonia related to the acquired immune deficiency syndrome (AIDS) the first 12 underwent routine fibreoptic bronchoscopy and bronchoalveolar lavage with or without transbronchial biopsy before treatment. Eight were found to have Pneumocystis carinii pneumonia and had typical clinical presentations with a prolonged history of symptoms, including a dry cough, and bilateral diffuse alveolar or interstitial shadowing in chest radiographs. Among the subsequent 13 cases, 11 had similar clinical presentations and were treated with high doses of intravenous co-trimoxazole without bronchoscopy first. Bronchoscopy was performed in those who deteriorated at any stage or failed to improve by the fifth day of treatment. Nine patients recovered and were discharged. In two patients who died P carinii pneumonia was confirmed in one but no diagnosis was made in the other. The early and late survival in both groups of patients was similar. In patients at high risk for AIDS who have clinical features suggestive of P carinii pneumonia starting treatment with intravenous co-trimoxazole is justified. The few patients who deteriorate or fail to respond should undergo bronchoscopy with bronchoalveolar lavage and transbronchial biopsy.

Treatment of uncomplicated gonorrhoea in women with a combination of rifampicin and erythromycin

One hundred women with uncomplicated gonorrhoea (in five cases due to penicillinase producing strains of Neisseria gonorrhoeae (PPNG)) were treated with a single oral dose of rifampicin 900 mg and erythromycin stearate 1 g. N gonorrhoeae was reisolated from the oropharynx of one patient, who was infected with a PPNG strain, but was eradicated from the genital tract in 100% of cases. The combination eradicated Chlamydia trachomatis from only 10 (28%) of the 36 patients infected. Side effects were predominantly mild and consisted of transient nausea. The treatment merits evaluation in areas with a high incidence of PPNG strains.