Abstract PD05-08: Genomic characterisation of invasive breast cancers with heterogeneous HER2 gene amplification

Aims: HER2 gene amplification is observed in up to 15% of breast carcinomas. In a rare subset of breast cancers classified as HER2-positive by immunohistochemistry and in situ hybridisation, HER2 overexpression and gene amplification are restricted to a subset of >30% but not all cancer cells. Here we sought to characterise the repertoire of gene copy number aberrations and somatic mutations in the HER2-positive and HER2-negative components of cases with heterogeneous HER2 overexpression and gene amplification.

Material and methods: Cases diagnosed as HER2 positive but with >30% but <100% of cells displaying HER2 overexpression were retrieved from the authors' institutions. HER2 heterogeneity status was re-assessed using immunohistochemistry and chromogenic and/ or fluorescence in situ hybridisation. For cases with confirmed HER2 gene amplification heterogeneity, HER2-positive and HER2-negative components were microdissected from tissue sections stained with the Herceptest antibody. DNA samples extracted from both components of each case were subjected to microarray-based comparative genomic hybridisation (aCGH), using a 32K BAC array platform with 50Kb resolution. The HER2-positive and HER2-negative components of cases with frozen material were also subjected to massively parallel targeted exome sequencing.

Results: Twelve cases yielded sufficient DNA for aCGH analysis. Tumours were preferentially ER positive (83%) and of histological grade 3 (67%). The HER2-positive and HER2-negative components of all cases shared most of the copy number aberrations. A pairwise comparison of the genomic profiles of the two components from each case revealed that in ten of the twelve cases, copy number aberrations in addition to 17q12 amplification encompassing the HER2 gene locus were restricted to one of the two components. Exome sequencing of two cases suggested that the HER2-positive and HER2-negative components from each case harboured >30 somatic mutations in common, including identical TP53 somatic mutations in both components of each case. The HER2-negative component of one of the cases displayed a somatic mutation in NRG2, an ERBB receptor ligand, and the HER2-negative component of the other case harboured a mutation in PTTG1IP, a proto-oncogene with putative oestrogen receptor elements.

Conclusions: Our results demonstrate that in HER2-positive breast cancers with heterogeneous HER2 gene amplification, the HER2-positive and HER2-negative components are clonally related. The distinct genomic profiles of HER2-positive and HER2-negative components, however, suggest that, at least in some of these cases, HER2 amplification may constitute a relatively late event in tumour evolution. Exome sequencing revealed mutations restricted to the HER2-negative components of HER2-positive tumours with heterogeneous HER2 overexpression/gene amplification, which may constitute potential drivers in the absence of HER2 overexpression/gene amplification.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD05-08.

Burden of postmenopausal osteoporosis in Germany: estimations from a disease model

This article describes the adaptation of a model assessing the incidence of osteoporotic fractures and prevalence of postmenopausal osteoporosis (PMO) in Germany.

PURPOSE

The purpose of this paper is to estimate the epidemiological burden of PMO in Germany from 2010 to 2020.

METHODS

For each year of the study, the 'incident cohort' (women experiencing a first osteoporotic fracture) was identified and run through a Markov model using 1-year cycles until 2020. Health states were based on the number of fractures (1, 2 or ≥3) and deaths. Although the fracture site was not explicitly accounted for in the model structure, the site (hip, vertebral, non-hip non-vertebral) was tracked for each health state. Transition probabilities reflected the site-specific risk of death and of subsequent fractures. Model inputs included population size and life tables from 1970 to 2020, incidence of fracture and BMD by age in the general population (mean and standard deviation).

RESULTS

In 2010, the number of osteoporotic fractures was estimated at 349,560 in women aged 50 years or more, including 80,177 hip and 48,550 vertebral fractures. By 2020, the population is expected to grow by 13.1 %. As a result, the number of fractures is predicted to increase by 15.2 %. The improvement in life expectancy is predicted to lead to a relatively smaller increase in the number of deaths attributable to fractures (+12.8 %), but also to an increase in the prevalence of women with multiple prior fractures (+25.5 %).

CONCLUSION

The PMO disease model, first developed for Sweden, was adapted to Germany. Due to the ageing of the population, the number of osteoporotic fractures is expected to increase markedly by +15.2 % by 2020.

Epidemiological burden of postmenopausal osteoporosis in France from 2010 to 2020: estimations from a disease model

This article estimates the present and future burden of postmenopausal osteoporosis in France in women aged 50 years and over.

METHODS

We adapted an existing model developed for Sweden to France. For each year of the study from 1970 to 2020, the 'incident cohort' (women experiencing a first osteoporotic fracture) was identified and run through a Markov model using annual cycles. Health states were based on the number of fractures (hip, vertebral, non-hip non-vertebral) and deaths. Transition probabilities reflected fracture site-specific risks of subsequent fractures and of death. Country-specific model inputs included population size and life tables from 1970 to 2020 and incidence of hip fracture.

RESULTS

The model estimated that the number of postmenopausal osteoporotic women was expected to increase from 3.0 million to 3.4 million between 2010 and 2020 (+15.3 %). Assuming that the incidence of fracture by age group does not change over time, the model predicted that the overall number of osteoporotic fractures would increase from 204,234 fractures in 2010 to 241,261 in 2020 (+18.1 %), hip (20.3 %), vertebral (19.0 %) and non-hip non-vertebral fractures (17.0 %).

CONCLUSION

The aging of the population is expected to drive a marked increase in the prevalence of osteoporosis and in the number of osteoporotic fractures. These data may assist future planning for appropriate heath care provision.

Reliability of simulator driving tool for evaluation of sleepiness, fatigue and driving performance

STUDY OBJECTIVE

To compare the impact of extended wakefulness (i.e., sleepiness) and prolonged driving (i.e., fatigue) at the wheel in simulated versus real-life driving conditions.

DESIGN

Participants drove on an INRETS-MSIS SIM2 simulator in a research laboratory or an open French highway during 3 nocturnal driving sessions. A dose-response design of duration of nocturnal driving was used: a 2 h short driving session (3-5 AM), a 4 h intermediate driving session (1-5 AM) and an 8 h long driving session (9 PM-5 AM).

PARTICIPANTS

Two groups of healthy male drivers (20 for simulated driving and 14 drivers for real driving; mean age±SD=22.3±1.6 years), free of sleep disorders.

MEASUREMENTS

Number of inappropriate line crossings, self-rated fatigue and sleepiness were recorded in the last hour of driving sessions to control the effects of prior waking time and time of day.

RESULTS

Compared to the daytime reference session, both simulated and real driving performance were affected by a short nocturnal driving session (P<.05 and P<.001, respectively). Extension of nocturnal driving duration affected simulated performance nonlinearly and more severely than that of real driving (P<.001). Compared to the daytime reference session, short nocturnal simulated and real driving sessions increased self-perceived fatigue and sleepiness. Real and simulated driving conditions had an identical impact on fatigue and sleepiness during extended periods of nocturnal driving.

CONCLUSIONS

In healthy subjects, the INRETS-MSIS SIM2 simulator appropriately measures driving impairment in terms of inappropriate line crossings related to extended wakefulness but has limitations to measure the impact of extended driving on drivers' performance.

Development and validation of a disease model for postmenopausal osteoporosis

This article describes the development of a model for postmenopausal osteoporosis (PMO) based on Swedish data that is easily adaptable to other countries.

INTRODUCTION

The aims of the study were to develop and validate a model to describe the current/future burden of PMO in different national settings.

METHODS

For validation purposes, the model was developed using Swedish data and provides estimates from 1990. For each year of the study, the "incident cohort" (women experiencing a first osteoporotic fracture) was identified and run through a Markov model using 1-year cycles until 2020. Health states were based on the number of fractures and death. Fracture by site (hip, vertebral, and non-hip non-vertebral) was tracked for each health state. Transition probabilities reflected site-specific risk of death and subsequent fractures. Bone mineral density (BMD) was included as a model output; model inputs included population size and life tables from 1970 to 2020, incidence of fracture, relative risk of subsequent fractures based on prior fracture, relative risk of death following a fracture by site, and BMD by age (mean and standard deviation).

RESULTS

Model predictions averaged across age groups estimated the incidence of hip, vertebral, and other osteoporotic fractures within a 5% margin of error versus published data. In Sweden, the number of osteoporotic fractures is expected to rise by 11.5% between 2009 and 2020, with a shift towards more vertebral fractures and multiple fractures.

CONCLUSION

The current PMO disease model is easily adaptable to other countries, providing a consistent measure of present and future burden of PMO in different settings.

Effect of Pedal Rate on Diurnal Variations in Cardiorespiratory Variables

Recently, it was observed that the freely chosen pedal rate of elite cyclists was significantly lower at 06:00 than at 18:00 h, and that ankle kinematics during cycling exhibits diurnal variation. The modification of the pedaling technique and pedal rate observed throughout the day could be brought about to limit the effect of diurnal variation on physiological variables. Imposing a pedal rate should limit the subject's possibility of adaptation and clarify the influence of time of day on physiological variables. The purpose of this study was to determine whether diurnal variation in cardiorespiratory variables depends on pedal rate. Ten male cyclists performed a submaximal 15 min exercise on a cycle ergometer (50% Wmax). Five test sessions were performed at 06:00, 10:00, 14:00, 18:00, and 22:00 h. The exercise bout was divided into three equivalent 5 min periods during which different pedal rates were imposed (70 rev x min(-1), 90 rev x min(-1) and 120 rev x min(-1)). No significant diurnal variation was observed in heart rate and oxygen consumption, whatever the pedal rate. A significant diurnal variation was observed in minute ventilation (p=0.01). In addition, the amplitude of the diurnal variation in minute ventilation depended on pedal rate: the higher the pedal rate, the greater the amplitude of its diurnal variation (p=0.03). The increase of minute ventilation throughout the day is mainly due to variation in breath frequency (p=0.01)--the diurnal variation of tidal volume (all pedal rate conditions taken together) being non-significant--but the effect of pedal rate x time of day interaction on minute ventilation specific to the higher pedal rate conditions (p=0.03) can only be explained by the increase of tidal volume throughout the day. Even though an influence of pedal rate on diurnal rhythms in overall physiological variables was not also evidenced, high pedal rate should have been imposed when diurnal variations of physiological variables in cycling were studied.

Time‐of‐Day Effects on Myoelectric and Mechanical Properties of Muscle During Maximal and Prolonged Isokinetic Exercise

The aim of this study was to examine the time-of-day (TOD) effects in myoelectric and mechanical properties of muscle during a maximal and prolonged isokinetic exercise. Twelve male subjects were asked to perform 50 maximal voluntary contractions (MVC) of the knee extensor muscles at a constant angular velocity of 2.09 rad . sec(-1), at 06 : 00 and 18 : 00 h. Torque and electromyographic (EMG) parameters were recorded for each contraction, and the ratio between these values was calculated to evaluate variations of the neuromuscular efficiency (NME) with fatigue and with TOD. The results indicated that maximal torque values (T(45)Max) was significantly higher (7.73%) in the evening than in the morning (p<0.003). The diurnal variation in torque decrease was used to define two phases. During the first phase (1st to the 26th repetition), torque values decreased fast and values were higher in the evening than in the morning, and during the second phase (27th to the 50th repetition), torque decreased slightly and reached a floor value that appeared constant with TOD. The EMG parameters (Root Mean Square; RMS) were modified with fatigue, but were not TOD dependent. The NME decrease-significantly with fatigue, showing that peripheral factors were mainly involved in the torque decrease. Furthermore, NME decrease was greater at 18 : 00 than at 06 : 00 h for the vastus medialis (p<0.05) and the vastus lateralis muscles (p<0.002), and this occurred during the first fatigue phase of the exercise. In conclusion, the diurnal variation of the muscle fatigue observed during a maximal and prolonged isokinetic exercise seems to reflect on the muscle, with a greater contractile capacity but a higher fatigability in the evening compared to the morning.

Diurnal Variations in Cycling Kinematics

Physiological and biomechanical constraints as well as their fluctuations throughout the day must be considered when studying determinant factors in the preferred pedaling rate of elite cyclists. The aim of this study was to monitor the diurnal variation of spontaneous pedaling rate and movement kinematics over the crank cycle. Twelve male competitive cyclists performed a submaximal exercise on a cycle ergometer for 15 min at 50% of their W(max). Two test sessions were performed at 06:00 and 18:00 h on two separate days to assess diurnal variation in the study variables. For each test session, the exercise bout was divided into three equivalent 5-min periods during which subjects were requested to use different pedal rates (spontaneous cadence, 70 and 90 rev min(-1)). Pedal rate and kinematics data (instantaneous pedal velocity and angle of the ankle) were collected. The results show a higher spontaneous pedal rate in the late afternoon than in the early morning (p < 0.001). For a given pedal rate condition, there was a less variation in pedal velocity during a crank cycle in the morning than in the late afternoon. Moreover, diurnal variations were observed in ankle mobility across the crank cycle, the mean plantar flexion observed throughout the crank cycle being greater in the 18:00 h test session (p < 0.001). These results suggest that muscular activation patterns during a cyclical movement could be under the influence of circadian fluctuations.

Effect of Pb-rich and Fe-rich entities during alteration of a partially vitrified metallurgical waste

Lead blast furnace (LBF) slags are mainly composed of an iron-silica-lime glass matrix and minor phases such as solid solutions of Mg-Cr-rich and Fe-Zn-rich spinel crystals, crystallized iron oxides such as wüstite and metallic lead droplets. In this study, results from Raman spectroscopy, transmission and scanning electron microscopy allow to argue that widely submicron iron-rich phases are very common in the glass matrix and could have an effect on the general alteration pattern of the glass matrix during leaching experiments. Open flow tests also point out close relationships between glass alteration ability and the presence of large lead droplets. According to numerous papers on nuclear glass leaching, acidic pH encountered in such open flow tests lead to preferential releases of the main alkali-earth metal composing the glass. Altered glass is mainly characterized by relative enrichments in iron. It is induced by high calcium or calcium-silicon depletions. Surprisingly, such type of alteration layer is not uniformly spread on the slag surface. In this work, it is also assumed that previous chemical analyses of the LBF glass matrix having micrometric resolution cannot give a realistic glass composition. A short discussion is also proposed about which characterization techniques can be used to correctly identify submicron iron-rich entities and evaluate their proportions and composition.

The influence of circadian rhythm on muscle activity and efficient force production during cycling at different pedal rates

The aim of this study was to examine the pedal rate and chronobiological impacts on muscle activity pattern and propulsive force production during cycling. Ten male competitive cyclists performed at 06:00 and 18:00 h a submaximal exercise on a cycle ergometer at a power output which elicited 50% of their respective W(max). The exercise was divided into 4 periods lasting 5 min each during which subjects were requested to use different pedal rates (free pedal rate, 70, 90 and 120 rev min-1) in random order. The study demonstrated that, under high pedal rate, several muscles exhibited a phase advance of activity. These modifications of temporal organization of muscle activity were not sufficient to keep an identical propulsive torque pattern. Time to peak torque was delayed when pedal rate increased. The effects of circadian fluctuation on electromyographic activity were limited to a later M. rectus femoris burst end and shorter activity duration for M. tibialis anterior at 06:00 h. From the results of this study, it seems that the influence of pedal rate in the range of torque fluctuation would depend on time-of-day of testing. The decrease in torque fluctuation due to pedal rate increase is reinforced when testing in the early morning. Taking this specific variable into consideration, the chronobiological effect increases the impact of pedal rate variations.

A longitudinal study on quality of life and depression in ALS patient–caregiver couples

OBJECTIVES

To evaluate the modification of quality of life (QoL) and depression in a series of amyotrophic lateral sclerosis (ALS) patient-caregiver couples during a period of 9 months and compare them to patients' ALS Functional Rating Scale (ALS-FRS).

METHODS

Depression was assessed with Zung Depression Scale (ZDS) and QoL with McGill Quality of Life Questionnaire (MQoL). Caregivers' burden was assessed with Caregiver Burden Inventory (CBI), and patients' feeling to be a burden with the Self-Perceived Burden Scale (SPBS).

RESULTS

Thirty-one ALS patient-caregiver couples were interviewed at baseline and after 9 months. The mean ALS-FRS score was 28.7 (SD 7) at baseline and 24.1 (6.9) at the second interview (p = 0.0001). Patients' mean MQoL score slightly increased from 6.8 (1.6) to 7 (1.1) (p = 0.07); their ZDS score slightly increased (43.2 [8.7] at baseline and 45.7 [9.3] at the second interview) but they remained in the not depressed range. Caregivers' mean MQoL score slightly decreased, and their mean ZDS increased from 38.9 (8.1) to 42.2 (8.7) (p = 0.02). The mean CBI score increased from 50.3 (17.6) to 55.8 (16.4) (p = 0.03).

CONCLUSIONS

We found a substantial steadiness of quality of life and depression in patients with amyotrophic lateral sclerosis over a 9-month period, vs a significant increase of burden and depression of their caregivers.

The influence of circadian rhythm during a sustained submaximal exercise and on recovery process

The purpose of this study was to examine the time-of-day effects on muscle fatigue and recovery process following an isometric fatiguing contraction. Sixteen male subjects were tested at two times (06:00h and 18:00h) and were requested to perform a sustained submaximal contraction of the elbow flexors, consisting in maintaining 40% of their absolute strength as long as they could. Isometric maximal voluntary contractions (MVC) were performed before (Pre), immediately after (Post), and up to 10min after the endurance task. Endurance time, peak torque (PT) and electromyographic (EMG) activities of the biceps brachii and triceps brachii were recorded and analysed. Results showed that under Pre-test conditions, PT developed at 18:00h was higher than at 06:00h. No time-of-day effect appears for the endurance time and EMG activities during the test. No time-of-day effect was observed on either MVC or EMG recovery. From the results of this study, it seems that both muscle fatigue and recovery process are not time-of-day dependent. We conclude that circadian rhythm of the force do not influence the evaluation of muscle capacities during a submaximal exercise corresponding at 40% of MVC.

The effect of pedal rate and time of day on the time to exhaustion from high-intensity exercise

The aim of this study was to examine the supposed influence of pedal rate on the diurnal fluctuation of the time to exhaustion from high-intensity exercise. Eleven male cyclists performed three tests at 06:00 h and three at 18:00 h at a free pedal rate (FPR) and two imposed pedal rates (80% and 120% of the FPR). They performed the tests until exhaustion using a power output corresponding to 95% maximal power (Pmax). Time to exhaustion, rectal temperature, oxygen consumption (.VO2), M. quadriceps, vastus medialis, M. biceps femoris electromyographic Root Mean Square activity rise (RMS slope), and blood lactate concentration were measured. The mean time to exhaustion recorded at 18:00 h (270.6+/-104.8 sec) was greater than at 06:00 h (233.9+/-84.9 sec). The time to exhaustion was significantly greater when the pedal rate was imposed at 80% versus 120% FPR. The blood lactate concentration and absolute core temperature at the point of exhaustion were significantly higher during tests done at 18:00 h. There was no diurnal variation in core temperature increase, .VO2, and RMS slope. The time-of-day effect for every variable did not depend on pedal rate. Diurnal variations in maximal aerobic endurance cannot be explained by a change in aerobic metabolism or in muscular fatigue. The origin of the diurnal variation in the time to exhaustion is likely to lie in greater participation in anaerobic metabolism. Also, the influence of temperature on neuromuscular functioning as an explanation for the diurnal variation in performance cannot be excluded in this study. The hypothesis on the basis of which pedal rate would influence diurnal variations in time to exhaustion in cycling was not validated by this research.

Caregiver time use in ALS

The authors evaluated the caregiver time for 70 patients with ALS. The mean number of caregivers per patient was 2.0 (SD 1.3). Caregiver time increased with worsening of disability (p = 0.0001). The most time-consuming duties were housekeeping, feeding, and toileting. With worsening of patients' disability, families relied increasingly on paid caregivers. Caregiver time is a hidden cost of ALS care and is a major burden for caregivers.