A comparison of the efficacy of trastuzumab deruxtecan in advanced HER2-positive breast cancer: active brain metastasis versus progressive extracranial disease alone

BACKGROUND

Trastuzumab deruxtecan (T-DXd) has demonstrated efficacy in patients with brain metastasis (BM), a group historically with poor outcomes. The prevalence of BMs in patients commencing T-DXd is currently unknown. No direct comparisons have been made of the activity of T-DXd in patients with active BM versus those with extracranial progression alone. This real-world study explored the prevalence of BMs in patients commencing T-DXd, the efficacy of T-DXd in active BM versus extracranial progression alone and the safety of T-DXd.

PATIENTS AND METHODS

Patients with human epidermal growth factor receptor 2-positive advanced breast cancer treated with T-DXd between June 2021 and February 2023 at our specialist cancer hospital were identified and notes reviewed. Clinicopathological information, prior treatment, the presence or absence of central nervous system (CNS) disease, outcomes and treatment-emergent adverse events (TEAEs) were recorded.

RESULTS

Twenty-nine female patients, with a median age of 52 years (interquartile range 44-62 years), were identified; the prevalence of BM was 41%. Median number of lines of prior therapy was 2 (range 2-6). At a median follow-up of 13.8 months, median progression-free survival (PFS) for the overall population was 13.9 months [95% confidence interval (CI) 12.4 months-not estimable (NE)], 16.1 months (95% CI 15.1 months-NE) for active BMs and 12.4 months (95% CI 8.3 months-NE) for progressive extracranial disease alone. The 12-month overall survival (OS) rate was 74% (95% CI 59% to 95%) in the overall population, and 83% (95% CI 58% to 100%) and 66% (95% CI 45% to 96%) for active BMs and extracranial disease only, respectively. Most common TEAEs were fatigue, alopecia, and constipation. In nine patients (31%, including two deaths), pneumonitis occurred.

CONCLUSION

In this real-world population, we demonstrate T-DXd to be effective in patients with active BMs and those with progressive extracranial disease alone. PFS and OS were numerically longer in those with active BMs. These data demonstrate that patients with active BM treated with T-DXd have at least comparable outcomes to those with extracranial disease alone. The high rate of pneumonitis warrants further consideration.

The intracortical excitability changes underlying the enhancing effects of rewards and punishments on motor performance

Monetary rewards and punishments enhance motor performance and are associated with corticospinal excitability (CSE) increases within the motor cortex (M1) during movement preparation. However, such CSE changes have unclear origins. Based on converging evidence, one possibility is that they stem from increased glutamatergic (GLUTergic) facilitation and/or decreased type A gamma-aminobutyric acid (GABAA)-mediated inhibition within M1. To investigate this, paired-pulse transcranial magnetic stimulation was used over the left M1 to evaluate intracortical facilitation (ICF) and short intracortical inhibition (SICI), indirect assays of GLUTergic activity and GABAA-mediated inhibition, in an index finger muscle during the preparation of sequences initiated by either the right index or little finger. Behaviourally, rewards and punishments enhanced both reaction and movement time. During movement preparation, regardless of rewards or punishments, ICF increased when the index finger initiated sequences, whereas SICI decreased when both the index and little fingers initiated sequences. This finding suggests that GLUTergic activity increases in a finger-specific manner whilst GABAA-mediated inhibition decreases in a finger-unspecific manner during preparation. In parallel, both rewards and punishments non-specifically increased ICF, but only rewards non-specifically decreased SICI as compared to neutral. This suggests that to enhance performance rewards both increase GLUTergic activity and decrease GABAA-mediated inhibition, whereas punishments selectively increase GLUTergic activity. A control experiment revealed that such changes were not observed post-movement as participants processed reward and punishment feedback, indicating they were selective to movement preparation. Collectively, these results map the intracortical excitability changes in M1 by which incentives enhance motor performance.

Bacterial lipopolysaccharide modulates immune response in the colorectal tumor microenvironment

Immune responses can have opposing effects in colorectal cancer (CRC), the balance of which may determine whether a cancer regresses, progresses, or potentially metastasizes. These effects are evident in CRC consensus molecular subtypes (CMS) where both CMS1 and CMS4 contain immune infiltrates yet have opposing prognoses. The microbiome has previously been associated with CRC and immune response in CRC but has largely been ignored in the CRC subtype discussion. We used CMS subtyping on surgical resections from patients and aimed to determine the contributions of the microbiome to the pleiotropic effects evident in immune-infiltrated subtypes. We integrated host gene-expression and meta-transcriptomic data to determine the link between immune characteristics and microbiome contributions in these subtypes and identified lipopolysaccharide (LPS) binding as a potential functional mechanism. We identified candidate bacteria with LPS properties that could affect immune response, and tested the effects of their LPS on cytokine production of peripheral blood mononuclear cells (PBMCs). We focused on Fusobacterium periodonticum and Bacteroides fragilis in CMS1, and Porphyromonas asaccharolytica in CMS4. Treatment of PBMCs with LPS isolated from these bacteria showed that F. periodonticum stimulates cytokine production in PBMCs while both B. fragilis and P. asaccharolytica had an inhibitory effect. Furthermore, LPS from the latter two species can inhibit the immunogenic properties of F. periodonticum LPS when co-incubated with PBMCs. We propose that different microbes in the CRC tumor microenvironment can alter the local immune activity, with important implications for prognosis and treatment response.

Assessment of COVID-19 outbreaks in long-term care facilities

BACKGROUND

The B.1.167.2 (Delta) variant quickly became the predominant circulating SARS-CoV-2 strain in the USA during summer 2021. Missouri identified a high number of outbreaks in long-term care facilities (LTCFs) across the state with low vaccination rates among LTCF staff members and poor adherence to mitigation measures within local communities.

AIM

To describe COVID-19 outbreaks that occurred in Missouri LTCFs impacting staff and residents during the surge of the Delta variant.

METHODS

Outbreaks of COVID-19 in 178 LTCFs were identified by the Missouri Department of Health and Senior Services. Case data from LTCFs with the highest burden of disease were analysed to assess disease transmission, vaccination status, and outcomes among residents and staff. Additional investigational measures included onsite visits to facilities with recent COVID-19 outbreaks in communities with substantial transmission to assess mitigation measures.

FINDINGS

During April 22^nd to July 29^th, 2021, 159 COVID-19 cases among 72 staff members and 87 residents were identified in 10 LTCFs. More than 74.7% of resident cases were vaccinated compared to 23.6% of staff cases. Vaccinated residents had a lower proportion of hospitalizations and deaths reported compared to unvaccinated residents. Data analysis and contact-tracing efforts from a sample of the facilities suggest that staff members were likely a major factor in introducing SARS-CoV-2 virus into the facilities. Adherence to COVID-19 mitigation measures varied at the visited facilities.

CONCLUSION

Data showed that vaccination rates varied between staff cases and resident cases in facilities with high-burden outbreaks. Differences were identified in mitigation practices in at least two facilities.

Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.

Comparison of actionable events detected in cancer genomes by whole-genome sequencing, in silico whole-exome and mutation panels

Background

Next-generation sequencing is used in cancer research to identify somatic and germline mutations, which can predict sensitivity or resistance to therapies, and may be a useful tool to reveal drug repurposing opportunities between tumour types. Multigene panels are used in clinical practice for detecting targetable mutations. However, the value of clinical whole-exome sequencing (WES) and whole-genome sequencing (WGS) for cancer care is less defined, specifically as the majority of variants found using these technologies are of uncertain significance.

Patients and methods

We used the Cancer Genome Interpreter and WGS in 726 tumours spanning 10 cancer types to identify drug repurposing opportunities. We compare the ability of WGS to detect actionable variants, tumour mutation burden (TMB) and microsatellite instability (MSI) by using in silico down-sampled data to mimic WES, a comprehensive sequencing panel and a hotspot mutation panel.

Results

We reveal drug repurposing opportunities as numerous biomarkers are shared across many solid tumour types. Comprehensive panels identify the majority of approved actionable mutations, with WGS detecting more candidate actionable mutations for biomarkers currently in clinical trials. Moreover, estimated values for TMB and MSI vary when calculated from WGS, WES and panel data, and are dependent on whether all mutations or only non-synonymous mutations were used. Our results suggest that TMB and MSI thresholds should not only be tumour-dependent, but also be sequencing platform-dependent.

Conclusions

There is a large opportunity to repurpose cancer drugs, and these data suggest that comprehensive sequencing is an invaluable source of information to guide clinical decisions by facilitating precision medicine and may provide a wealth of information for future studies. Furthermore, the sequencing and analysis approach used to estimate TMB may have clinical implications if a hard threshold is used to indicate which patients may respond to immunotherapy.

•

Genome analysis revealed that treatment biomarkers are shared across solid tumours, highlighting repurposing opportunities.

•

Comprehensive panels detect most known biomarkers; however, WGS detects more biomarkers for treatments in clinical trials.

•

TMB is well correlated between sequencing methods, but absolute values vary and are dependent on mutation types considered.

P-631 Day Length Predicts Ovulatory Shifts in Women’s Reproductive Function

Study question

Is there a relationship between day length and ovulation rate in women of reproductive age?

Summary answer

Analysis showed that increasing day length is associated with higher ovulation rate in women of reproductive age in both Sweden and the United States (US).

What is known already

Historically, winter months have been characterised by threatening survival conditions, such as reduced food availability and lower temperatures. Day length, or photoperiod, provides a reliable indication of upcoming seasonal changes, which promotes season-specific adaptations to behaviours and reproductive systems in mammals. To avoid the survival threats the winter months present, mammals with long gestation periods typically exhibit increased breeding as photoperiods increase. As humans also possess long gestation periods, it may be that humans similarly adapt to increasing photoperiods by exhibiting seasonal shifts in reproductive functioning.

Study design, size, duration

This retrospective analysis of basal body temperature (BBT) data from the Natural Cycles contraceptive app included approximately 115,000 Natural Cycles users’ data, amounting to approximately 1.3 million cycles from May 2014 - January 2021. BBT was used to confirm ovulation, the rate of which was calculated and compared to the number of hours daylight users experienced based on the geographical location in which they had registered for the app.

Participants/materials, setting, methods

We exclude cycles with missing data for any of the studied variables leaving ∼180k Swedish and ∼150K US cycles. The Meteostat library supplied the temperature on the start date of each user cycle. The Suntime library was used to determine the number of hours of daylight users were exposed to on the start date of each cycle, which used the geographic coordinates of the users’ reported country of residence.

Main results and the role of chance

Menstrual Cycle data from approximately 115 thousand Natural Cycles app users aged between 18-62 from two geographic groups, Sweden and the US. Data from cycles during and immediately following the event of a miscarriage, pregnancy, or instance of taking an emergency contraceptive, as well as the two cycles immediately following a completed pregnancy. Using a generalised logistic mixed-effects model, implementation via GPBoost, user-specific variation in ovulation rate as a function of location-specific day length was assessed while controlling for age, cycle length, body mass index (BMI), daily temperature, and education level. We find that day length is significantly correlated with higher ovulation (p < 0.01) in both the US and Swedish cohort.

Limitations, reasons for caution

Ovulation rate and day length may have emerged as a function a several underlying mechanisms, including the optimisation of conditions for childbirth, the optimisation of conditions for conception and early embryonic development, or a decrease in ovulation during the darker, winter months as a result of investment in immune function.

Wider implications of the findings

Photoperiod may be an important regulator of human reproductive activity, providing some preliminary evidence of seasonal changes to women’s ovulatory functioning. Furthermore, birth rate as a measurement of seasonal reproductive patterns in humans may not be as stable or accurate a measure for contemporary analyses of women’s reproductive functioning.

Trial registration number

000000

300. Pediatric Center Evaluation of the BioFire® Blood Culture Identification 2 Panel Versus the Original BioFire®FilmArray® Blood Culture Identification Panel for the Detection of Microorganisms and Resistance Markers in Positive Blood Cultures

Background

Studies show a rising annual incidence of severe sepsis, with bloodstream infections continuing to impact children. Rapid identification of causative agents and timely administration of targeted therapy can positively impact patient outcomes and improve antibiotic stewardship.

The BioFire^® Blood Culture Identification 2 (BCID2) Panel (BioFire Diagnostics, LLC), an updated version of the FDA-cleared BioFire^® FilmArray^® Blood Culture Identification (BCID) Panel, designed for use on positive blood cultures (PBCs), assesses 43 analytes, including 17 novel analytes (8 bacterial, 2 fungal, and 7 antimicrobial resistance genes), with a similar turnaround time.

Methods

De-identified residual PBCs for which clinician-ordered testing per standard of care (SoC) had been performed were enrolled and tested with an Investigation-Use-Only version of the BCID2 Panel. Only one positive bottle per patient was enrolled. Results of BCID2 and BCID were compared.

Results

116 PBCs (48 aerobic and 68 anaerobic) were evaluated using the BioFire BCID2 Panel and results were compared to the BioFire BCID Panel. Of the 116 cases, 103 were positive on both the BioFire BCID2 Panel and the BioFire BCID Panel. Ten cases were negative on both tests. While the two panels showed 97% agreement, three cases were discrepant. Using culture (SoC) as the tiebreaker, two cases were false positive and one case was false negative on the BioFire BCID Panel. In all three cases, results from culture and the BioFire BCID2 Panel were in agreement. As expected, no organisms were detected on the BioFire BCID2 Panel in PBCs from 10% (12/116) of PBC bottles where culture identified only organisms that are not part of the panel menu. With the BioFire BCID2 Panel’s expanded platform, two cases identified as Enterobacteriaceae on the BioFire BCID Panel were identified to the genus level on the BioFire BCID2 Panel; 31 cases detected to the genus level on the BioFire BCID Panel were identified to the species level on the BioFire BCID2 Panel.

Conclusion

Overall, the BioFire BCID2 Panel performed well against the BioFire BCID Panel for identification of bloodstream pathogens and provided additional discrimination of some pathogens to the genus or species level.

Data presented are from assays that have not been cleared or approved for diagnostic use.

Disclosures

All Authors: No reported disclosures

OP0203-HPR EVALUATION OF A 10-WEEK PROGRESSIVE RESISTANCE TRAINING PROGRAMME FOR PEOPLE WITH INFLAMMATORY ARTHRITIS

Background:

Inflammatory Arthritis [IA] adversely affects well-being, function, fatigue and strength1. Guidelines recommend people with IA should exercise to improve strength and cardiovascular fitness2. In 2015, our team introduced an evidence-based Progressive Resistance Training Programme [PRTP] for IA3.

Objectives:

To evaluate the effectiveness of a PRTP within a United Kingdom National Health Service setting.

Methods:

A pre- to post-treatment evaluation was conducted. People with IA attending Rheumatology Physiotherapy were offered a supervised PRTP (1 hour x 10 weeks): 7 exercises at 70-80% 1-repetition maximum (3 x 8-12 repetitions). Treatment outcomes included Health Assessment Questionnaire [HAQ], EQ5D-5L, 30s sit-to-stand [STS], Self-Efficacy (SARAH Trial) [SE], Grip Strength and FACIT-Fatigue [FACIT-F]. Changes in outcomes were analysed using Paired Samples t-tests and standardised mean difference (SMD).

Results:

201 patients commenced the programme between May 2015 and April 2019, with 121 participants providing complete pre-post HAQ data. Diagnoses included Rheumatoid Arthritis (n=149), Psoriatic Arthritis (n=42), Juvenile Idiopathic Arthritis (n=5), Enteropathic IA (n=2), Oligoarthritis (n=1), Reactive Arthritis (n=1) and Undifferentiated IA (n=1). Age (mean ± SD) = 56.8 ± 14.8 years; number of sessions attended = 7.7 ± 3.4.

There were no differences between those recorded as not completing the PTRP (n=54; 72% women; age 55.0 ± 14.6 years; HAQ 0.99 ± 0.70) versus the others (n=147; 78% women; age 57.5 ± 14.8; HAQ 0.86 ± 0.65). A pragmatic decision was made to analyse all available data for each outcome.

Table 1.

Analysis of PRTP outcomes * Indicates clinical improvement.

Outcome measurePre-treatmentPost-treatmentMean difference(95% CI)p-valueStandardised mean difference(95% CI)HAQmax score 3 (n=121)0.83 ± 0.650.70 ± 0.67-0.13(-0.07, -0.19)p<0.001-0.20*(-0.46, 0.07)EQ5D VASmax score 100 (n=119)70.0 ± 16.376.7 ± 15.26.7(9.4, 3.9)p<0.0010.42*(0.17, 0.68)STSnumber in 30s (n=118)13.2 ± 4.916.2 ± 5.33.0(3.6, 2.5)p<0.0010.59*(0.33, 0.85)SEmax score 70 (n=117)52.3 ± 10.458.6 ± 8.06.3(8.3, 4.4)p<0.0010.68*(0.41, 0.94)Grip Strength kg force(n=62)20.3 ± 9.423.6 ± 10.63.3(4.8, 1.7)p<0.0010.33*(-0.03, 0.68)FACIT-Fmax score 52(n=58)30.9 ± 11.535.5 ± 12.04.6(7.2, 2.1)p=0.0010.39*(0.02, 0.76)

Conclusion:

All outcome measures demonstrated statistically significant improvements. Notably, minimal clinically important differences were achieved in STS and FACIT-F. STS correlates to lower limb power, balance and endurance, and is a predictor of falls4. Fatigue significantly impacts function in people with IA5, often limiting confidence and willingness to participate in exercise activities6.

Effective evidence-based PRTPs for people with IAs can be delivered by Physiotherapists. Improvements in function, wellbeing, self-efficacy, strength and fatigue are achievable, however, exploration of the clinical relevance of these observed changes is recommended. Further research exploring patients’ perspectives of the PRTP and adherence to long-term exercise is needed.

References:

[1]Cooneyet al. (2011) Benefits of Exercise in Rheumatoid ArthritisJ. Aging Res.Vol 2011

[2]Rausch Ostoffet al. (2018) 2018 EULAR recommendations for physical activity in people with inflammatory arthritis and osteoarthritisAnn Rheum Dis77(9)

[3]Lemmeyet al. (2009) Effects of high-intensity resistance training in patients with rheumatoid arthritis: a randomized controlled trialArthritis Rheum16(12)

[4]Beaudartet al. (2019) Assessment of Muscle Function and Physical Performance in Daily Clinical PracticeCalcif. Tissue Int.105(1)

[5]Dureset al. (2016) Patient preferences for psychological support in inflammatory arthritis: a multicentre surveyAnn Rheum Dis75(1)

[6]Rongen-van Dartelet al. (2015) Effect of Aerobic Exercise Training on Fatigue in Rheumatoid Arthritis: A Meta-AnalysisArth Care Res67(8)

Disclosure of Interests:

None declared

Broadband, millimeter-wave antireflection coatings for large-format, cryogenic aluminum oxide optics

We present two prescriptions for broadband ($ {\sim} 77 - 252\;{\rm GHz} $), millimeter-wave antireflection coatings for cryogenic, sintered polycrystalline aluminum oxide optics: one for large-format (700 mm diameter) planar and plano-convex elements, the other for densely packed arrays of quasi-optical elements-in our case, 5 mm diameter half-spheres (called "lenslets"). The coatings comprise three layers of commercially available, polytetrafluoroethylene-based, dielectric sheet material. The lenslet coating is molded to fit the 150 mm diameter arrays directly, while the large-diameter lenses are coated using a tiled approach. We review the fabrication processes for both prescriptions, then discuss laboratory measurements of their transmittance and reflectance. In addition, we present the inferred refractive indices and loss tangents for the coating materials and the aluminum oxide substrate. We find that at 150 GHz and 300 K the large-format coating sample achieves $ (97 \pm 2)\% $ transmittance, and the lenslet coating sample achieves $ (94 \pm 3)\% $ transmittance.

Whole-genome sequencing reveals clinically relevant insights into the aetiology of familial breast cancers

BACKGROUND

Whole-genome sequencing (WGS) is a powerful method for revealing the diversity and complexity of the somatic mutation burden of tumours. Here, we investigated the utility of tumour and matched germline WGS for understanding aetiology and treatment opportunities for high-risk individuals with familial breast cancer.

PATIENTS AND METHODS

We carried out WGS on 78 paired germline and tumour DNA samples from individuals carrying pathogenic variants in BRCA1 (n = 26) or BRCA2 (n = 22) or from non-carriers (non-BRCA1/2; n = 30).

RESULTS

Matched germline/tumour WGS and somatic mutational signature analysis revealed patients with unreported, dual pathogenic germline variants in cancer risk genes (BRCA1/BRCA2; BRCA1/MUTYH). The strategy identified that 100% of tumours from BRCA1 carriers and 91% of tumours from BRCA2 carriers exhibited biallelic inactivation of the respective gene, together with somatic mutational signatures suggestive of a functional deficiency in homologous recombination. A set of non-BRCA1/2 tumours also had somatic signatures indicative of BRCA-deficiency, including tumours with BRCA1 promoter methylation, and tumours from carriers of a PALB2 pathogenic germline variant and a BRCA2 variant of uncertain significance. A subset of 13 non-BRCA1/2 tumours from early onset cases were BRCA-proficient, yet displayed complex clustered structural rearrangements associated with the amplification of oncogenes and pathogenic germline variants in TP53, ATM and CHEK2.

CONCLUSIONS

Our study highlights the role that WGS of matched germline/tumour DNA and the somatic mutational signatures can play in the discovery of pathogenic germline variants and for providing supporting evidence for variant pathogenicity. WGS-derived signatures were more robust than germline status and other genomic predictors of homologous recombination deficiency, thus impacting the selection of platinum-based or PARP inhibitor therapy. In this first examination of non-BRCA1/2 tumours by WGS, we illustrate the considerable heterogeneity of these tumour genomes and highlight that complex genomic rearrangements may drive tumourigenesis in a subset of cases.

Abstract P5-10-01: Using whole genome sequencing and somatic mutation signatures to unravel insight into familial breast cancer aetiology

Approximately 10-15% of breast cancers are associated with a strong family history of disease. Pathogenic variants in BRCA1, BRCA2 or other moderate to highly penetrant susceptibility genes (e.g. TP53, ATM, CHEK2, PALB2 and PTEN) account for a number of breast cancer families. However, for over 50% of families the underlying genetic contribution to their risk remains unknown (termed here as non-BRCA1/2). This has a profound impact for how individuals and their families are managed in the clinic. We applied whole genome sequencing (WGS) to determine whether somatic mutation analysis can reveal insight into the aetiology of familial breast cancer. The full repertoire of somatic mutations was evaluated in 26 BRCA1, 22 BRCA2 and 32 non-BRCA1/2 tumours; including SNPs, indels, copy number changes and structural rearrangements, and mutational signatures. Genomes were also analysed using the HRD Index and HRDetect, as predictors of homologous recombination deficiency. BRCA1, BRCA2 and non-BRCA1/2 tumours exhibited a different burden of mutations, a different spectrum of mutational signatures and different telomere length. Based on collective patterns of mutation signatures, tumours were classified as 'BRCA1-like', 'BRCA2-like' or 'non-BRCA1/2-like' with a 15% rate of tumour re-classification from their original clinical BRCA status. The results demonstrate the power of WGS to differentiate between BRCA1 and BRCA2 driven tumours; in the identification of double-pathogenic germline mutation carriers based on the resulting somatic mutation signature; and in the interpretation of BRCA unclassified variants. WGS of tumour genomes reveals fascinating insights into tumour aetiology and could compliment current genetic testing of breast cancer families.

Citation Format: Simpson P, Nones K, Johnson J, Newell F, Patch A-M, Thorne H, Kazakoff S, De Luca X, Parsons M, Ferguson K, Reid L, McCart Reed A, Srihari S, Lakis V, Davidson A, Mukhopadhyay P, Holmes O, Xu Q, Wood S, Leonard C, Beasley J, Degasperi A, Nik-Zainal S, Ragan M, Spurdle A, Khanna KK, Lakhani S, Pearson J, Chenevix-Trench G, Waddell N. Using whole genome sequencing and somatic mutation signatures to unravel insight into familial breast cancer aetiology [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 P5-10-01.

Abstract P3-08-03: Dissecting the heterogeneity of metaplastic breast cancer: A morphological, immunohistochemical and genomic analysis of a large cohort

Although rare, Metaplastic Breast Carcinomas (MBC) account for significant global breast cancer mortality. This subgroup is extremely heterogeneous and by definition exhibits metaplastic change to squamous and/or mesenchymal elements, including but not limited to spindle, squamous, chondroid, osseous and rhabdomyoid elements. The WHO working group recognizes that the current classification is inadequate and in the interim, has suggested a purely descriptive classification. The mixed epithelial-mesenchymal morphology has led to speculation that MBC represent 'stem cell tumours'; in support of this, MBC have been shown to have a CD44+/CD24-/low phenotype. Clinically, patients present with tumours that are larger (higher stage), have increased likelihood of distant metastases at presentation and overall, have a reduced 5-year survival rate compared to Invasive Carcinoma-NST. Hence, this is a unique subtype with poor outcome but without a robust classification or understanding of the biology to aid clinical management. We present a detailed morphological, immunohistochemical and genomic analysis of a large series of MBC (n=347), as amassed through the Asia-Pacific MBC consortium. We consider our morphological dissection using the WHO subtyping guidelines and show that an increasing number of phenotypes in a mixed MBC (classified as WHO_1) significantly associates with a poor prognosis. Immunohistochemical analysis showed that a pure spindle (WHO_5) is significantly less likely to express vimentin, CK5/6, CK14, and CK19 than a mixed WHO_1 with spindle features. Similarly, a WHO_1 with chondroid features is less likely to express EGFR than WHO_1 with chondroid features and rhabdoid or osseous differentiation. Across the cohort, positivity for the AE1/3 antibody and a lack of EGFR expression both significantly associate with a better outcome. We report no significant association between patient age at diagnosis and breast cancer specific survival, nor between age and specific WHO MBC subtypes. We report a significant association between WHO_1 types and increasing tumour grade, and also between tumour size and grade, with tumour size being a highly significant prognostic indicator in this cohort. Our exome sequencing confirms a significant enrichment for TP53 and PTEN mutations in MBC, and intriguingly for concurrent mutations of TP53, PTEN and PIK3CA. A novel enrichment for NF1 mutations is also presented. In summary, we provide a thorough assessment of a large cohort of MBC, including morphology, survival, IHC and exome sequencing, and present our analysis contextualized by the WHO guidelines, extending the existing knowledge base of this rare tumour type.

Citation Format: McCart Reed AE, Kalaw E, Nones K, Bettington M, Lim M, Bennett J, Johnstone K, Kutasovic JR, Kazakoff S, Xu QC, Saunus JM, Reid LE, Black D, Niland C, Ferguson K, Gresshoff I, Raghavendra A, Liu JC, Kalinowski L, Reid AS, Davidson M, Pearson JV, Yamaguchi R, Harris G, Tse G, Papadimos D, Pathmanathan R, Pathmanathan N, Tan PH, Fox S, O'Toole S, Waddell N, Simpson PT, Lakhani SR. Dissecting the heterogeneity of metaplastic breast cancer: A morphological, immunohistochemical and genomic analysis of a large cohort [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 P3-08-03.

A Six Year Prospective Study of Fibrinogen and Other Risk Factors Associated with Mortality in Stable Claudicants

A total of 333 patients with stable intermittent claudication at recruitment were followed up for 6 years to determine risk factors associated with subsequent mortality. Cardiovascular diseases were the underlying cause of death in 78% of the 114 patients who died. The strongest independent predictor of death during the follow-up period was the plasma fibrinogen level, an increase of 1 g/l being associated with a nearly two-fold increase in the probability of death within the next 6 years. Age, low ankle/brachial pressure index and a past history of myocardial infarction also increased the probability of death during the study period. The plasma fibrinogen level is a valuable index of those patients with stable intermittent claudication at high risk of early mortality. The results also provide further evidence for the involvement of fibrinogen in the pathogenesis of arterial disease.

Vortex dynamics and frequency splitting in vertically coupled nanomagnets

We explored the dynamic response of a vortex core in a circular nanomagnet by manipulating its dipole-dipole interaction with another vortex core confined locally on top of the nanomagnet. A clear frequency splitting is observed corresponding to the gyrofrequencies of the two vortex cores. The peak positions of the two resonance frequencies can be engineered by controlling the magnitude and direction of the external magnetic field. Both experimental and micromagnetic simulations show that the frequency spectra for the combined system is significantly dependent on the chirality of the circular nanomagnet and is asymmetric with respect to the external bias field. We attribute this result to the strong dynamic dipole-dipole interaction between the two vortex cores, which varies with the distance between them. The possibility of having multiple states in a single nanomagnet with vertical coupling could be of interest for magnetoresistive memories.

Nontuberculous mycobacteria in gastrostomy fed patients with cystic fibrosis

Multi-drug resistant Mycobacterium abscessus complex (MABSC) is a form of Nontuberculous mycobacteria (NTM) of special, international concern in Cystic Fibrosis (CF). We hypothesised that gastric juice and percutaneous endoscopic gastrostomy (PEG) feeding devices might yield MABSC isolates. Gastric juice and sputa from sixteen adult PEG fed CF patients and five replaced PEG tubes were studied. Bacterial and fungal isolates were cultured. Mycobacterium were identified by rpoB, sodA and hsp65 gene sequencing and strain typed using variable number tandem repeat. Bacteria and/or fungi grew from all gastric juice, sputa and PEG samples. MABSC were detected in 7 patients. Five had MABSC in their sputum. Two had an identical MABSC strain in their sputum and gastric juice and one had the same strain isolated from their PEG tube and sputum. Two patients who were sputum sample negative had MABSC isolated in their gastric juice or PEG tube. MABSC were therefore identified for the first time from a gastric sample in a minority of patients. We conclude that gastric juice and PEG-tubes may be a potential source of MABSC isolates in CF patients, and these findings warrant further study.

Population-based study demonstrating an increase in colorectal cancer in young patients

BACKGROUND

New Zealand has among the highest rates of colorectal cancer in the world and is an unscreened population. The aim of this study was to determine the trends in incidence and tumour location in the New Zealand population before the introduction of national colorectal cancer screening.

METHODS

Data were obtained from the national cancer registry and linked to population data from 1995 to 2012. Incidence rates for colorectal cancer by sex, age (less than 50 years, 50-79 years, 80 years or more) and location (proximal colon, distal colon and rectum) were assessed by linear regression.

RESULTS

Among patients aged under 50 years, the incidence of distal colonic cancer in men increased by 14 per cent per decade (incidence rate ratio (IRR 1·14), 95 per cent c.i. 1·00 to 1·30; P = 0·042); the incidence of rectal cancer in men increased by 18 per cent (IRR 1·18, 1·06 to 1·32; P = 0·002) and that in women by 13 per cent (IRR 1·13, 1·02 to 1·26; P = 0·023). In those aged 50-79 years, there was a reduction in incidence per decade of proximal, distal and rectal cancers in both sexes. In the group aged 80 years and over, proximal cancer incidence per decade increased by 19 per cent in women (IRR 1·19, 1·13 to 1·26; P < 0·001) and by 25 per cent in men (IRR 1·25, 1·18 to 1·32; P < 0·001); among women, the incidence of distal colonic cancer decreased by 8 per cent (IRR 0·92, 0·86 to 0·98); P = 0·012), as did that of rectal cancer (IRR 0·92, 0·86 to 0·97; P = 0·005).

CONCLUSION

The increasing incidence of rectal cancer among younger patients needs to be considered when implementing screening strategies.

Translating colorectal cancer genetics into clinically useful biomarkers

Colorectal cancer (CRC) is a major health problem worldwide accounting for over a million deaths annually. While many patients with Stage II and III CRC can be cured with combinations of surgery, radiotherapy and chemotherapy, this is morbid costly treatment and a significant proportion will suffer recurrence and eventually die of CRC. Increased understanding of the molecular pathogenesis of CRC has the potential to identify high risk patients and target therapy more appropriately. Despite increased understanding of the molecular events underlying CRC development, established molecular techniques have only produced a limited number of biomarkers suitable for use in routine clinical practice to predict risk, prognosis and response to treatment. Recent rapid technological developments, however, have made genomic sequencing of CRC more economical and efficient, creating potential for the discovery of genetic biomarkers that have greater diagnostic, prognostic and therapeutic capabilities for the management of CRC. This paper reviews the current understanding of the molecular pathogenesis of CRC, and summarizes molecular biomarkers that surgeons will encounter in current clinical use as well as those under development in clinical and preclinical trials. New molecular technologies are reviewed together with their potential impact on the understanding of the molecular pathogenesis of CRC and their potential clinical utility in classification, diagnosis, prognosis and targeting of therapy.

Microbiological profiles of sputum and gastric juice aspirates in Cystic Fibrosis patients

Gastro-Oesophageal Reflux (GOR) is a key problem in Cystic Fibrosis (CF), but the relationship between lung and gastric microbiomes is not well understood. We hypothesised that CF gastric and lung microbiomes are related. Gastric and sputum cultures were obtained from fifteen CF patients receiving percutaneous endoscopic gastrostomy feeding. Non-CF gastric juice data was obtained through endoscopy from 14 patients without lung disease. Bacterial and fungal isolates were identified by culture. Molecular bacterial profiling used next generation sequencing (NGS) of the 16S rRNA gene. Cultures grew bacteria and/or fungi in all CF gastric juice and sputa and in 9/14 non-CF gastric juices. Pseudomonas aeruginosa(Pa) was present in CF sputum in 11 patients, 4 had identical Pa strains in the stomach. NGS data from non-CF gastric juice samples were significantly more diverse compared to CF samples. NGS showed CF gastric juice had markedly lower abundance of normal gut bacteria; Bacteroides and Faecalibacterium, but increased Pseudomonas compared with non-CF. Multivariate partial least squares discriminant analysis demonstrated similar bacterial profiles of CF sputum and gastric juice samples, which were distinct from non-CF gastric juice. We provide novel evidence suggesting the existence of an aerodigestive microbiome in CF, which may have clinical relevance.

The effect of intrauterine infusion of dextrose on clinical endometritis cure rate and reproductive performance of dairy cows

The main objective of this study was to evaluate the intrauterine administration use of 200 mL of 50% dextrose solution as a treatment against clinical endometritis (CE); CE cure rate and reproductive performance were evaluated. Additionally, the association of several relevant risk factors, such as retained placenta (RP), metritis, CE, anovulation, hyperketonemia, and body condition score with reproductive performance, early embryonic mortality, and CE were evaluated. A total of 1,313 Holstein cows housed on 4 commercial dairy farms were enrolled in the study. At 7±3 DIM cows were examined for metritis and had blood collected to determine serum β-hydroxybutyrate concentration. To determine if cows had ovulated at least once before 44±3 DIM, the presence of a corpus luteum was evaluated by ovarian ultrasonography at 30±3 DIM and at 44±3 DIM. At 30±3 DIM, CE was diagnosed using the Metricheck device (SimcroTech, Hamilton, New Zealand); cows with purulent or mucopurulent vaginal discharge were diagnosed as having CE. Cows diagnosed with CE (n=175) were randomly allocated into 2 treatment groups: treatment (intrauterine infusion of 200 mL of 50% dextrose) or control (no infusion). Clinical endometritis cows were re-evaluated as described above at 44±3 DIM, and cows that were free of purulent or mucopurulent vaginal discharge were considered cured. Intrauterine infusion of dextrose tended to have a detrimental effect on CE cure rate, and treatment did not have an effect on first-service conception rate and early embryonic mortality. A multivariable Cox's proportional hazard model was performed to evaluate the effect of several variables on reproductive performance; the variables RP, CE, parity, anovulation, and the interaction term between parity and anovulation were associated with hazard of pregnancy. Cows that did not have RP or CE were more likely to conceive than cows that were diagnosed with RP or CE. Cows that had RP were at 3.36 times higher odds of losing their pregnancy than cows that did not have RP. In addition, cows diagnosed with CE were at 2.16 higher odds of losing their pregnancy than cows without CE. In conclusion, intrauterine infusion of 200 mL of 50% dextrose solution as a treatment for CE had a strong statistical tendency to decrease CE cure rate, did not improve first-service conception rate and early embryonic mortality, and did not decrease calving-to-conception interval.

Discovery of Time Variation of the Intensity of Molecular Lines in IRC+10216 in The Submillimeter and Far Infrared Domains

We report on the discovery of strong intensity variations in the high rotational lines of abundant molecular species towards the archetypical circumstellar envelope of IRC+10216. The observations have been carried out with the HIFI instrument on board Herschel and with the IRAM 30-m telescope. They cover several observing periods spreading over 3 years. The line intensity variations for molecules produced in the external layers of the envelope most probably result from time variations in the infrared pumping rates. We analyze the main implications this discovery has on the interpretation of molecular line emission in the envelopes of Mira-type stars. Radiative transfer calculations have to take into account both the time variability of infrared pumping and the possible variation of the dust and gas temperatures with stellar phase in order to reproduce the observation of molecular lines at different epochs. The effect of gas temperature variations with stellar phase could be particularly important for lines produced in the innermost regions of the envelope. Each layer of the circumstellar envelope sees the stellar light radiation with a different lag time (phase). Our results show that this effect must be included in the models. The sub-mm and FIR lines of AGB stars cannot anymore be considered as safe intensity calibrators.

Active and passive heat stress similarly compromise tolerance to a simulated hemorrhagic challenge

Passive heat stress increases core and skin temperatures and reduces tolerance to simulated hemorrhage (lower body negative pressure; LBNP). We tested whether exercise-induced heat stress reduces LBNP tolerance to a greater extent relative to passive heat stress, when skin and core temperatures are similar. Eight participants (6 males, 32 ± 7 yr, 176 ± 8 cm, 77.0 ± 9.8 kg) underwent LBNP to presyncope on three separate and randomized occasions: 1) passive heat stress, 2) exercise in a hot environment (40°C) where skin temperature was moderate (36°C, active 36), and 3) exercise in a hot environment (40°C) where skin temperature was matched relative to that achieved during passive heat stress (∼38°C, active 38). LBNP tolerance was quantified using the cumulative stress index (CSI). Before LBNP, increases in core temperature from baseline were not different between trials (1.18 ± 0.20°C; P > 0.05). Also before LBNP, mean skin temperature was similar between passive heat stress (38.2 ± 0.5°C) and active 38 (38.2 ± 0.8°C; P = 0.90) trials, whereas it was reduced in the active 36 trial (36.6 ± 0.5°C; P ≤ 0.05 compared with passive heat stress and active 38). LBNP tolerance was not different between passive heat stress and active 38 trials (383 ± 223 and 322 ± 178 CSI, respectively; P = 0.12), but both were similarly reduced relative to active 36 (516 ± 147 CSI, both P ≤ 0.05). LBNP tolerance is not different between heat stresses induced either passively or by exercise in a hot environment when skin temperatures are similarly elevated. However, LBNP tolerance is influenced by the magnitude of the elevation in skin temperature following exercise induced heat stress.

Visualizing domain wall and reverse domain superconductivity

In magnetically coupled, planar ferromagnet-superconductor (F/S) hybrid structures, magnetic domain walls can be used to spatially confine the superconductivity. In contrast to a superconductor in a uniform applied magnetic field, the nucleation of the superconducting order parameter in F/S structures is governed by the inhomogeneous magnetic field distribution. The interplay between the superconductivity localized at the domain walls and far from the walls leads to effects such as re-entrant superconductivity and reverse domain superconductivity with the critical temperature depending upon the location. Here we use scanning tunnelling spectroscopy to directly image the nucleation of superconductivity at the domain wall in F/S structures realized with Co-Pd multilayers and Pb thin films. Our results demonstrate that such F/S structures are attractive model systems that offer the possibility to control the strength and the location of the superconducting nucleus by applying an external magnetic field, potentially useful to guide vortices for computing application.

When superconductivity emerges in a thin superconductor grown on a ferromagnet, it does so in an array of interacting superconducting and normally conducting channels. Maria Iavarone and colleagues use scanning tunnelling microscopy to image how these channels form and interact.

Survival of myeloma patients following the introduction of thalidomide as a second-line therapy: a retrospective study at a single New Zealand centre

AIM

This retrospective study compares the overall survival (OS) of multiple myeloma (MM) patients following treatment at a New Zealand hospital over a period in which novel therapies were available but restricted, almost exclusively, to thalidomide as a second-line therapy.

METHODS

Clinical, laboratory and OS data were collected on 361 MM patients who were treated at Christchurch Hospital during 2000-2010. Patients were subdivided according to the clinical criteria used to determine front-line treatment decisions. Older patients (age ≥66, n = 180) generally received standard-dose chemotherapy without autologous stem cell transplant (SCT) and formed one group. Younger patients were further subdivided according to whether they received autologous SCT (n = 89), allogeneic SCT (n = 24) or no SCT (n = 68).

RESULTS

Older patients had a significantly shorter OS (P < 0.0001) than younger patients (median OS = 25 vs 78 months) however treated. Analysis of relative survival demonstrated that the increased mortality of older patients was greater than that attributable to normal ageing. Younger patients who received no transplant had a significantly shorter OS (P < 0.0001) than those who received autologous SCT or allogeneic SCT with 5-year survivals of 38%, 70% and 72% respectively. Use of novel therapies was significantly higher in younger than older patients (60% vs 47%, P = 0.011).

CONCLUSIONS

The front-line treatment groupings of hospital MM patients had significantly different survivals. The OS of SCT ineligible patients remains poor despite the introduction of thalidomide.