Vibrational signatures of dynamic excess proton storage between primary amine and carboxylic acid groups

Ammonium and carboxylic moieties play a central role in proton-mediated processes of molecular recognition, charge transfer or chemical change in (bio)materials. Whereas both chemical groups constitute acid-base pairs in organic salt-bridge structures, they may as well host excess protons in acidic environments. The binding of excess protons often precedes proton transfer reactions and it is therefore of fundamental interest, though challenging from a quantum chemical perspective. As a benchmark for this process, we investigate proton storage in the amphoteric compound 5-aminovaleric acid (AV), within an intramolecular proton bond shared by its primary amine and carboxylic acid terminal groups. Infrared ion spectroscopy is combined with ab initio Molecular Dynamics (AIMD) calculations to expose and rationalize the spectral signatures of protonated AV and its deuterated isotopologues. The dynamic character of the proton bond confers a fluxional structure to the molecular framework, leading to wide-ranging bands in the vibrational spectrum. These features are reproduced with remarkable accuracy by AIMD computations, which serves to lay out microscopic insights into the excess proton binding scenario.

Circulating tumour cells are associated with histopathological growth patterns of colorectal cancer liver metastases

Histopathological Growth Patterns (HGPs) have prognostic and predictive value in patients with Colorectal Liver Metastases (CRLM). This study examined whether preoperative measurement of Circulating Tumour Cells (CTCs) is associated with HGP. CTCs were prospectively enumerated in 7.5 ml of blood using the FDA-approved CellSearch system in patients who underwent local treatment of CRLM with curative intent between 2008 and 2021. All CTC samples were collected on the day of local treatment. Patients treated with neoadjuvant chemotherapy for CRLM or with extrahepatic disease at the time of CTC sampling were excluded. HGP was scored retrospectively following the current consensus guidelines. The association between CTCs and HGP was investigated through multivariable logistic regression. Data were available for 177 patients, desmoplastic HGP (dHGP) was observed in 34 patients (19%). There were no statistically significant differences in patient and tumour characteristics between dHGP and non-dHGP at baseline. Patients with dHGP had longer overall - and disease-free survival (logrank p = 0.003 and 0.003, respectively) compared to patients with non-dHGP. CTCs were not detected in 25(74%) of dHGP patients and in 68(48%) of non-dHGP patients (chi-squared p = 0.006). Preoperative absence of CTCs was the only significant predictor for dHGP in multivariable logistic regression (Odds Ratio 2.7, 95%CI 1.1-6.8, p = 0.028), Table 3. Preoperative absence of CTCs is associated with dHGP in chemo naive CRLM patients without extrahepatic disease. Based on our results, CTC count alone is not sufficient to preoperatively identify HGPs, but integration of CTC count in multivariable prediction models may aid the preoperative identification of HGPs of CRLM.

Structural Determination of Lysine-Linked Cisplatin Complexes via IRMPD Action Spectroscopy: NNs and NO- Binding Modes of Lysine to Platinum Coexist

Despite its success as an anticancer drug, cisplatin suffers from resistance and produces side effects. To overcome these limitations, amino-acid-linked cisplatin analogues have been investigated. Lysine-linked cisplatin, Lysplatin, (Lys)PtCl₂, exhibited outstanding reactivity toward DNA and RNA that differs from that of cisplatin. To gain insight into its differing reactivity, the structure of Lysplatin is examined here using infrared multiple photon dissociation (IRMPD) action spectroscopy. To probe the influence of the local chemical environment on structure, the deprotonated and sodium-cationized Lysplatin complexes are examined. Electronic structure calculations are performed to explore possible modes of binding of Lys to Pt, their relative stabilities, and to predict their infrared spectra. Comparisons of the measured IRMPD and predicted IR spectra elucidate the structures contributing to the experimental spectra. Coexistence of two modes of binding of Lys to Pt is found where Lys binds via the backbone and side-chain amino nitrogen atoms, NN_s, or to the backbone amino and carboxylate oxygen atoms, NO^-. Glycine-linked cisplatin and arginine-linked cisplatin complexes have previously been found to bind only via the NO^- binding mode. Present results suggest that the NN_s binding conformers may be key to the outstanding reactivity of Lysplatin toward DNA and RNA.

Standardizing resolution definition in scanning helium microscopy

Resolution is a key parameter for microscopy, but methods for standardizing its definition are often poorly defined. For a developing technique such as scanning helium microscopy, it is critical that a consensus-based protocol for determining instrument resolution is prepared as a written standard to allow both comparable quantitative measurements of surface topography and direct comparisons between different instruments. In this paper we assess a range of quantitative methods for determining instrument resolution and determine their relative merits when applied to the specific case of the scanning helium microscope (SHeM). Consequently, we present a preliminary protocol for measuring the resolution in scanning helium microscopy based upon utilizing appropriate test samples with sets of slits of well-defined dimensions to establish the quantitative resolution of any similar instrument.

Disease activity in inflammatory bowel disease patients is associated with increased liver fat content and liver fibrosis during follow-up

PURPOSE

Liver steatosis is a frequently reported condition in patients with inflammatory bowel disease (IBD). Different factors, both metabolic and IBD-associated, are believed to contribute to the pathogenesis. The aim of our study was to calculate the prevalence of liver steatosis and fibrosis in IBD patients and to evaluate which factors influence changes in steatosis and fibrosis during follow-up.

METHODS

From June 2017 to February 2018, demographic and biochemical data was collected at baseline and after 6-12 months. Measured by transient elastography (FibroScan), liver steatosis was defined as Controlled Attenuation Parameter (CAP) ≥248 and fibrosis as liver stiffness value (Emed) ≥7.3 kPa. IBD disease activity was defined as C-reactive protein (CRP) ≥10 mg/l and/or fecal calprotectin (FCP) ≥150 μg/g. Univariate and multivariate regression analysis was performed; a p-value of ≤0.05 was considered significant.

RESULTS

Eighty-two out of 112 patients were seen for follow-up; 56% were male. The mean age was 43 ± 16.0 years, and mean BMI was 25.1 ± 4.7 kg/m². The prevalence of liver steatosis was 40% and of fibrosis was 20%. At baseline, 26 patients (32%) had an active episode of IBD. Using a multivariate analysis, disease activity at baseline was associated with an increase in liver steatosis (B = 37, 95% CI 4.31-69.35, p = 0.027) and liver fibrosis (B = 1.2, 95% CI 0.27-2.14, p = 0.016) during follow-up.

CONCLUSIONS

This study confirms the relatively high prevalence of liver steatosis and fibrosis in IBD patients. We demonstrate that active IBD at baseline is associated with both an increase in liver steatosis and fibrosis during follow-up.

Structural determination of arginine-linked cisplatin complexes via IRMPD action spectroscopy: arginine binds to platinum via NO- binding mode

Cisplatin, (NH₃)₂PtCl₂, has been known as a successful metal-based anticancer drug for more than half a century. Its analogue, Argplatin, arginine-linked cisplatin, (Arg)PtCl₂, is being investigated because it exhibits reactivity towards DNA and RNA that differs from that of cisplatin. In order to understand the basis for its altered reactivity, the deprotonated and sodium cationized forms of Argplatin, [(Arg-H)PtCl₂]^- and [(Arg)PtCl₂ + Na]⁺, are examined by infrared multiple photon dissociation (IRMPD) action spectroscopy in the IR fingerprint and hydrogen-stretching regions. Complementary electronic structure calculations are performed using density functional theory approaches to characterize the stable structures of these complexes and to predict their infrared spectra. Comparison of the theoretical IR spectra predicted for various stable conformations of these Argplatin complexes to their measured IRMPD spectra enables determination of the binding mode(s) of Arg to the Pt metal center to be identified. Arginine is found to bind to Pt in a bidentate fashion to the backbone amino nitrogen and carboxylate oxygen atoms in both the [(Arg-H)PtCl₂]^- and [(Arg)PtCl₂ + Na]⁺ complexes, the NO^- binding mode. The neutral side chain of Arg also interacts with the Pt center to achieve additional stabilization in the [(Arg-H)PtCl₂]^- complex. In contrast, Na⁺ binds to both chlorido ligands in the [(Arg)PtCl₂ + Na]⁺ complex and the protonated side chain of Arg is stabilized via hydrogen-bonding interactions with the carboxylate moiety. These findings are consistent with condensed-phase results, indicating that the NO^- binding mode of arginine to Pt is preserved in the electrospray ionization process even under variable pH and ionic strength.

Task Adaptations as a Function of Content Knowledge: A Functional Analysis

Purpose: The purpose of the study was to investigate how teachers' pedagogical content knowledge (PCK) in the form of task adaptations differed as a function of content knowledge. Method: Participants were three elementary school teachers (two females and one male) and their students (n = 66). Functional analysis of instructional events (i.e., adaptations) between teachers and students was used to examine PCK before and after a content knowledge workshop in crawl swimming. The appropriateness of the adaptations was measured and all data were collected through live observation by trained observers. Results: All teachers increased their average number of task adaptations per lesson after the content knowledge workshop. Appropriateness of adaptations increased substantially for two teachers but decreased for one teacher. Discussion/Conclusion: Functional analysis of student-teacher interactions is a valuable tool to examine teachers' PCK. The interrelationship between student- and teacher behavior can be modified through a content knowledge workshop.

Characterization of male breast cancer: results of the EORTC 10085/TBCRC/BIG/NABCG International Male Breast Cancer Program

Background

Male breast cancer (BC) is rare, managed by extrapolation from female BC. The International Male BC Program aims to better characterize and manage this disease. We report the results of part I, a retrospective joint analysis of cases diagnosed during a 20-year period.

Methods

Patients with follow-up and tumor samples, treated between 1990 and 2010, in 93 centers/9 countries. Samples were centrally analyzed in three laboratories (the United Kingdom, the Netherlands and the United States).

Results

Of 1822 patients enrolled, 1483 were analyzed; 63.5% were diagnosed between 2001 and 2010, 57 (5.1%) had metastatic disease (M1). Median age at diagnosis: 68.4 years. Of 1054 M0 cases, 56.2% were node-negative (N0) and 48.5% had T1 tumors; 4% had breast conserving surgery (BCS), 18% sentinel lymph-node biopsy; half received adjuvant radiotherapy; 29.8% (neo)adjuvant chemotherapy and 76.8% adjuvant endocrine therapy (ET), mostly tamoxifen (88.4%). Per central pathology, for M0 tumors: 84.8% ductal invasive carcinomas, 51.5% grade 2; 99.3% estrogen receptor (ER)-positive; 81.9% progesterone receptor (PR)-positive; 96.9% androgen receptor (AR)-positive [ER, PR or AR Allred score ≥3]; 61.1% Ki67 expression low (<14% positive cells); using immunohistochemistry (IHC) surrogates, 41.9% were Luminal-A-like, 48.6% Luminal-B-like/HER-2-negative, 8.7% HER-2-positive, 0.3% triple negative. Median follow-up: 8.2 years (0.0-23.8) for all, 7.2 years (0.0-23.2), for M0, 2.6 years (0.0-12.7) for M1 patients. A significant improvement over time was observed in age-corrected BC mortality. BC-specific-mortality was higher for men younger than 50 years. Better overall (OS) and recurrence-free survival (RFS) were observed for highly ER+ (P = 0.001), highly PR+ (P = 0.002), highly AR+ disease (P = 0.019). There was no association between OS/RFS and HER-2 status, Ki67, IHC subtypes nor grade.

Conclusions

Male BC is usually ER, PR and AR-positive, Luminal B-like/HER2-negative. Of note, 56% patients had T1 tumors but only 4% had BCS. ER was highly positive in >90% of cases but only 77% received adjuvant ET. ER, PR and AR were associated with OS and RFS, whereas grade, Ki67 and IHC surrogates were not. Significant improvement in survival over time was observed.

Abstract P6-19-01: Evaluation of multiple transcriptomic gene risk signatures in male breast cancer

Introduction: Male breast cancer (MBC) is a rare disease accounting for less than 1% of all breast cancers (BC) and 1% of all cancers in males. The clinical management is largely extrapolated from female BC. Several multigene assays are increasingly used to guide clinical treatment decisions in female BC, however there is little data on the utility of these tests in MBC.

Methods: Here we present the gene expression results of 380 M0, ER+ve, HER2-ve MBCs enrolled in the Part 1 (retrospective joint analysis) International Male Breast Cancer Program of 1483 patients diagnosed between 1990-2010 (Cardoso et al. Annals of Oncology, 2018). Using a custom Nanostring™ panel comprised of the genes from the commercial risk tests Prosigna®, OncotypeDx® and Mammaprint®, risk scores and intrinsic subtyping data were generated to recapitulate the commercial tests as described by Bayani and Yao et al (npjBreast Cancer, 2017). Survival outcomes by risk classification were analyzed using Cox models with time-dependent covariates when the proportional hazard assumption was not met and adjusted for clinical and treatment variables.

Results: Prosigna-like risk scores identified 99 (26.1%) as low-risk, 159 (41.8%) as intermediate-risk, and 122 (32.1%) as high-risk. Using the TAILORx cut-off (25) for OncotypeDx-like risk of recurrence scoring, 158 (41.6%) were identified as low-risk, while 222 (58.4%) were identified as high-risk. MammaPrint-like results identified 175 (46.1%) as low-risk and 205 (53.9%) as high-risk. Overall, patients classified as high-risk had higher grade, more nodal involvement, larger tumors, and more frequently treated with chemotherapy than low-risk patients. Survival analyses demonstrated clear clinical utility for each test, showing patients at high-risk with poor relapse-free survival (RFS) as compared to patients classified as low-risk: Prosigna-like RFS at 3-years (HR=2.20, 95% CI, 1.28-3.80); Oncotype-like RFS at 3-years (HR=1.92, 95% CI, 1.17-3.17); MammaPrint-like RFS (HR=1.51, 95% CI, 1.00-2.27); with similar findings for distant relapse-free survival (DRFS) and overall survival (OS). Across outcomes and all gene signatures, patients with concordant Low/Low risk classification had better prognosis than those with concordant High/High risk classification. PAM50 intrinsic subtyping identified 147 (38.7%) as Luminal A, 57 (15.0%) as Luminal B, 80 (21.1%) as Her2-enriched and 96 (25.3%) as Basal-like; showing overall 34.5% concordance to clinic-pathological subtyping by central pathology (95% CI, 29.7%-39.5%). Comparison between the tests in the MBC cohort and a comparable cohort of female BC from the Tamoxifen Exemestane Adjuvant Multinational (TEAM) trial processed in the same way will be presented.

Conclusion: Common transcriptomic assays designed to assess residual risk, validated in female BC, provide similar information in male BC patients. Not surprisingly, disagreement between test results at the individual patient level was observed. To our knowledge, this is the largest study of MBC assayed to generate risk scores of the current commercial BC tests to demonstrate their clinical utility and their differences and similarity to female BC.

This work has been funded by the Breast Cancer Research Foundation (BCRF).

Citation Format: Bayani J, Poncet C, Yao CQ, Crozier C, Anouk N, Piper T, Cunningham C, Sobol M, Aebi S, Benstead K, Bogler O, Dal Lago L, Fraser J, Hilbers FH, Hedenfalk I, Korde L, Linderholm B, Martens J, Middleton L, Murray M, Kelly C, Nilsson C, Nowaczyk M, Peeters S, Peric A, Porter P, Schröder C, Rubio IT, Ruddy KJ, van Asperen C, Van Den Weyngaert D, van Deurzen C, van Leeuwen-Stok E, Vermeij J, Winer E, Boutros PC, Giordano SH, Cardoso F, Bartlett JM. Evaluation of multiple transcriptomic gene risk signatures in male breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-19-01.

Low temperature approach for high density electrical feedthroughs for neural implants using maskless fabrication techniques

Implantable electronic packages for neural implants utilize reliable electrical feedthroughs that connect the inside of a sealed capsule to the components that are exposed to the surrounding body tissue. With the ongoing miniaturization of implants requiring ever higher integration densities of such feedthroughs new technologies have to be investigated. The presented work investigates the sealing of vertical feedthroughs in aluminum-oxide-substrates with gold stud-bumps. The technology enables integration densities of up to 1600/cm ² while delivering suitable water leak rates for realistic implantation durations of miniaturized packages (feedthrough-count $>50$, package-volume $<2$ cm $^{3})$ of more than 50 years. All manufacturing steps require temperatures below $420 ^{\circ}\mathrm {C}$ and are suitable for maskless rapid prototyping.

Image formation in the scanning helium microscope

The scanning helium microscope (SHeM) is a new addition to the array of available microscopies, particularly for delicate materials that may suffer damage under techniques utilising light or charged particles. As with all other microscopies, the specifics of image formation within the instrument are required to gain a full understanding of the produced micrographs. We present work detailing the basics of the subject for the SHeM, including the specific nature of the projection distortions that arise due to the scattering geometry. Extension of these concepts allowed for an iterative ray tracing Monte Carlo model replicating diffuse scattering from a sample surface to be constructed. Comparisons between experimental data and simulations yielded a minimum resolvable step height of (67 ± 5) µm and a minimum resolvable planar angle of (4.3 ± 0.3)° for the instrument in question.

Deamidation of Protonated Asparagine-Valine Investigated by a Combined Spectroscopic, Guided Ion Beam, and Theoretical Study

Peptide deamidation of asparaginyl residues is a spontaneous post-translational modification that is believed to play a role in aging and several diseases. It is also a well-known small-molecule loss channel in the MS/MS spectra of protonated peptides. Here we investigate the deamidation reaction, as well as other decomposition pathways, of the protonated dipeptide asparagine-valine ([AsnVal + H]+) upon low-energy activation in a mass spectrometer. Using a combination of infrared ion spectroscopy, guided ion beam tandem mass spectrometry, and theoretical calculations, we have been able to identify product ion structures and determine the energetics and mechanisms for decomposition. Deamidation proceeds via ammonia loss from the asparagine side chain, initiated by a nucleophilic attack of the peptide bond oxygen on the γ-carbon of the Asn side chain. This leads to the formation of a furanone ring containing product ion characterized by a threshold energy of 129 ± 5 kJ/mol (15 kJ/mol higher in energy than dehydration of [AsnVal + H]+, the lowest energy dissociation channel available to the system). Competing formation of a succinimide ring containing product, as has been observed for protonated asparagine-glycine ([AsnGly + H]+) and asparagine-alanine ([AsnAla + H]+), was not observed here. Quantum-chemical modeling of the reaction pathways confirms these subtle differences in dissociation behavior. Measured reaction thresholds are in agreement with predicted theoretical reaction energies computed at several levels of theory.

Abstract P5-23-01: Clinical and biological characterization of male breast cancer (BC) EORTC 10085/TBCRC 029/BOOG 2013-02/BIG 2-07: Baseline results from the prospective registry

BACKGROUND: Through the International Male Breast Cancer Program, a prospective registry for male BC was created with the goals of evaluating 1) the clinical and biological features of this disease and 2) assessing feasibility of a prospective therapeutic clinical trial.

METHODS: All men, with any stage histologically proven invasive breast cancer, age 3 18 years, and newly presenting at the participating institutions (within 3 months prior) were eligible. Patients were enrolled for 30 months after activation of the first center, through February 2017. Per the study design, if &lt;100 men enrolled, the study would be considered a failure and therapeutic trials would not be pursued through this network. Epidemiologic data, staging, pathologic features, and BRCA status were collected. Treatment and outcome data collection is ongoing. Optional collection of FFPE tumor samples, blood, and QOL were performed in the US, the Netherlands, and Latin America. Clinical database lock for this report was May 30, 2017. We currently report patient and disease characteristics and will update with patterns of treatment for the presentation. Outcomes and biological samples will be analyzed in the future.

RESULTS: 557 patients were enrolled: 75% in Europe, 20% in United States, 5% in other countries. 6.3% of patients had missing forms. Median age was 67 years (range 26-92). 93% were diagnosed 2010-2017. Among patients with complete data, 79% presented with a breast mass. 88% were M0 and 12% M1. Among M0 patients: 47%, 39%, 2%, and 11% had T1, T2, T3, and T4 disease respectively; 52% were N0. Overall, 98% had ER+ disease and 11% had HER2+ cancer. 14% had grade 1, 56% had grade 2, and 30% had grade 3 tumors. Among 112 men who underwent BRCA1 testing, 1 was positive. Among 118 men who had BRCA2 testing, 18 (15%) were positive. 21% of men had prior or concurrent malignancies, with the following most common sites: prostate, non-melanoma skin, colorectal, and melanoma. The prevalence of previously identified possible risk factors for male breast cancer were: overweight/obesity (72%), former/current smoker (51%), current alcohol 31 drink daily (41%), family history of breast cancer (35%), gynecomastia (16%), history radiation exposure (8%), use of anti-androgens (1%), and use of estrogens (1%).

CONCLUSION: Through an international collaborative effort, we were able to prospectively accrue 557 patients to a male breast cancer registry. These results demonstrate feasibility of pursuing a therapeutic clinical trial in men with breast cancer. In addition, this study shows the relatively low uptake of BRCA testing, high rates of concurrent/prior malignancy, and the rates of potentially modifiable risk factors in this patient population.

Funding from Breast Cancer Research Foundation, Susan G. Komen, Dutch Pink Ribbon Foundation, Swedish Breast Cancer Association (BRO) and EBCC Council.

Citation Format: Giordano SH, Schröder CP, Poncet C, van Leeuwen-Stok E, Linderholm B, Abreu MH, Rubio I, Van Poznak C, Morganstern D, Cameron D, Vleugel MM, Smilde TJ, Bozovic-Spasojevic I, Korde L, Russell NS, den Hoed IDM, Honkoop AH, van der Velden AWG, van 't Riet M, Dijkstra N, Bogler O, Goulioti T, Hilsenbeck S, Ruddy KJ, Wolff A, van Deurzen CHM, Martens J, Bartlett JMS, Aalders K, Tryfonidis K, Cardoso F. Clinical and biological characterization of male breast cancer (BC) EORTC 10085/TBCRC 029/BOOG 2013-02/BIG 2-07: Baseline results from the prospective registry [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-23-01.

Long-term follow-up and quality of life after robot assisted sacrohysteropexy

OBJECTIVE

The aim of this study is to investigate the effect of robot assisted laparoscopic sacrohysteropexy (RALS), with preservation of the uterus, in patients with pelvic organ prolapse on short and long term outcome. We report on (anatomical) status of the prolaps and the associated health related quality of life of women treated with RALS before and five years after surgery.

STUDY DESIGN

A prospective cohort study in a teaching hospital in The Netherlands was performed. Quality of life was assessed pre-operative, post-operative and five years after RALS using the UDI/IIQ validated self-questionnaire designed for Dutch-speaking patients. Clinical and operative data were prospectively collected up to five years. Statistical analysis of categorical data was performed with the paired T-test. Descriptive statistics were computed with the use of standard methods for means, median and proportions.

RESULTS

Hundred women with utero vaginal prolapse were treated with RALS with preservation of the uterus. The overall success rate of pelvic organ prolapse (POP) was 89.2%. After surgery the quality of life improved (P<0.05) Overall health status, based on a 0-100% visual analogue scale (VAS), improved from 72.6% pre-operative to 82.2% six weeks postoperative (P<0.05). Postoperative patients experienced less feelings of nervousness (P=0.01), shame (P<0.05) and frustration (P<0.05). The positive effects on these feelings remained present after five years. The learning curve shows a decrease in operating time with gained experience.

CONCLUSION

RALS has proven to be a safe and effective treatment for uterine preserving surgery in cases of pelvic organ prolapse. The long term anatomical outcomes and quality of life after RALS compare favorably with laparoscopic and open hysteropexy.

A simple counter-flow cooling system for a supersonic free-jet beam source assembly

A simple design for an inexpensive, cooled, free-jet beam source is described. The source assembly features an integrated cooling system as supplied by a counter-flow of chilled nitrogen, and is composed primarily of off-the-shelf tube fittings. The design facilitates rapid implementation and eases subsequent alignment with respect to any downstream beamline aperture. The source assembly outlined cools the full length of the stagnation volume, offering temperature control down to 100 K and long-term temperature stability better than ±1 K.

Abstract S4-07: Tamoxifen resistance driven by the DNA cytosine deaminase APOBEC3B in recurrent estrogen receptor positive breast cancer

Recent studies have implicated the DNA cytosine deaminase APOBEC3B as a major source of mutation in breast cancer. APOBEC3B explains a large proportion of both dispersed and clustered cytosine mutations, the latter of which are also called kataegis. APOBEC3B expression levels correlate with poor outcomes for patients with estrogen receptor positive breast cancer. While targeted therapies, such as tamoxifen, are available to treat these tumors, secondary drug resistance often develops. Here we suppressed endogenous APOBEC3B in the estrogen receptor positive breast cell line MCF-7L with shRNA. Lowered levels of APOBEC3B did not affect in vitro growth or sensitivity to estradiol. In a xenograft model of tamoxifen therapy, suppression of APOBEC3B associated with prolonged responses to tamoxifen (p&lt;0.05). Furthermore, APOBEC3B over-expression did not affect in vitro cell growth but accelerated the development of tamoxifen-resistant tumors in vivo. In addition, we studied two separate cohorts of 285 breast cancer patients who received first line treatment with tamoxifen for recurrent disease. High APOBEC3B expression levels measured in the primary tumor associated significantly with unfavorable progression free survival in multivariate analysis that included the traditional predictive factors (age, dominant relapse site, disease-free interval, estrogen receptor and progesterone receptor, and adjuvant chemotherapy; HR=1.67, p=0.0001). The median period of progression free survival was 7.5 months for patients with APOBEC3B high primary tumors and 13.3 months for those with APOBEC3B low tumors (p&lt;0.0.0001). These studies demonstrate that APOBEC3B drives resistance to endocrine treatment with tamoxifen in recurrent disease.

Citation Format: Harris R, Law E, Sieuwerts A, LaPara K, Leonard B, Starrett G, Temiz NA, Sweep F, Span P, Foekens J, Martens J, Yee D. Tamoxifen resistance driven by the DNA cytosine deaminase APOBEC3B in recurrent estrogen receptor positive breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S4-07.

Hamilton's rule, inclusive fitness maximization, and the goal of individual behaviour in symmetric two-player games

Hamilton's original work on inclusive fitness theory assumed additivity of costs and benefits. Recently, it has been argued that an exact version of Hamilton's rule for the spread of a pro-social allele (rb > c) holds under nonadditive pay-offs, so long as the cost and benefit terms are defined as partial regression coefficients rather than pay-off parameters. This article examines whether one of the key components of Hamilton's original theory can be preserved when the rule is generalized to the nonadditive case in this way, namely that evolved organisms will behave as if trying to maximize their inclusive fitness in social encounters.

Unlocking new contrast in a scanning helium microscope

Delicate structures (such as biological samples, organic films for polymer electronics and adsorbate layers) suffer degradation under the energetic probes of traditional microscopies. Furthermore, the charged nature of these probes presents difficulties when imaging with electric or magnetic fields, or for insulating materials where the addition of a conductive coating is not desirable. Scanning helium microscopy is able to image such structures completely non-destructively by taking advantage of a neutral helium beam as a chemically, electrically and magnetically inert probe of the sample surface. Here we present scanning helium micrographs demonstrating image contrast arising from a range of mechanisms including, for the first time, chemical contrast observed from a series of metal–semiconductor interfaces. The ability of scanning helium microscopy to distinguish between materials without the risk of damage makes it ideal for investigating a wide range of systems.

Scanning helium microscopy uses neutral atoms to image traditionally challenging materials (e.g. delicate, insulating and magnetic samples) non-destructively with absolute surface sensitivity. This work reports the first observation of chemical contrast in helium microscopy via inelastic scattering.

A highly contrasting scanning helium microscope

We present a scanning helium microscope equipped to make use of the unique contrast mechanisms, surface sensitivity, and zero damage imaging the technique affords. The new design delivers an order of magnitude increase in the available helium signal, yielding a higher contrast and signal-to-noise ratio. These improvements allow the microscope to produce high quality, intuitive images of samples using topological contrast, while setting the stage for investigations into further contrast mechanisms.

Functional variants at the 11q13 risk locus for breast cancer regulate cyclin D1 expression through long-range enhancers

Analysis of 4,405 variants in 89,050 European subjects from 41 case-control studies identified three independent association signals for estrogen-receptor-positive tumors at 11q13. The strongest signal maps to a transcriptional enhancer element in which the G allele of the best candidate causative variant rs554219 increases risk of breast cancer, reduces both binding of ELK4 transcription factor and luciferase activity in reporter assays, and may be associated with low cyclin D1 protein levels in tumors. Another candidate variant, rs78540526, lies in the same enhancer element. Risk association signal 2, rs75915166, creates a GATA3 binding site within a silencer element. Chromatin conformation studies demonstrate that these enhancer and silencer elements interact with each other and with their likely target gene, CCND1.

Imiquimod 5% cream as pretreatment of Mohs micrographic surgery for nodular basal cell carcinoma in the face: a prospective randomized controlled study

BACKGROUND

Imiquimod 5% cream can reduce or clear superficial and small nodular basal cell carcinoma (BCC). It could be used as a pretreatment of Mohs micrographic surgery (MMS) to decrease defect size.

OBJECTIVES

To study if a pretreatment with imiquimod 5% cream decreases defect size after MMS. In addition, to study the effect on the number of Mohs stages and reconstruction time.

METHODS

Seventy patients aged >18 years with a primary nodular BCC in the face were included. The imiquimod group used imiquimod 5% cream for 4 weeks, before MMS. The control group was treated with MMS only. Tumour and defect sizes were measured. We noted the number of Mohs stages, reconstruction time and side-effects.

RESULTS

The median percentage increase in area from tumour size at baseline to the post-MMS defect for the imiquimod group was significantly less compared with the control group, 50% vs. 147% (P < 0·001). A tendency towards fewer Mohs stages in the imiquimod group was observed and the reconstruction time was significantly shorter in this group (P = 0·01).

CONCLUSIONS

Imiquimod 5% cream as pretreatment of MMS significantly reduced the tumour size in primary nodular BCC and reduced the surgical defect size. Further research is necessary to investigate cost-effectiveness.

Relocatable fixation systems in intracranial stereotactic radiotherapy. Accuracy of serial CT scans and patient acceptance in a randomized design

PURPOSE

The goal was to provide a quantitative evaluation of the accuracy of three different fixation systems for stereotactic radiotherapy and to evaluate patients' acceptance for all fixations.

METHODS

A total of 16 consecutive patients with brain tumours undergoing fractionated stereotactic radiotherapy (SCRT) were enrolled after informed consent (Clinical trials.gov: NCT00181350). Fixation systems evaluated were the BrainLAB® mask, with and without custom made bite-block (fixations S and A) and a homemade neck support with bite-block (fixation B) based on the BrainLAB® frame. The sequence of measurements was evaluated in a randomized manner with a cross-over design and patients' acceptance by a questionnaire.

RESULTS

The mean three-dimensional (3D) displacement and standard deviations were 1.16 ± 0.68 mm for fixation S, 1.92 ± 1.28 and 1.70 ± 0.83 mm for fixations A and B, respectively. There was a significant improvement of the overall alignment (3D vector) when using the standard fixation instead of fixation A or B in the craniocaudal direction (p = 0.037). Rotational deviations were significantly less for the standard fixation S in relation to fixations A (p = 0.005) and B (p = 0.03). EPI imaging with off-line correction further improved reproducibility. Five out of 8 patients preferred the neck support with the bite-block.

CONCLUSION

The mask fixation system in conjunction with a bite-block is the most accurate fixation for SCRT reducing craniocaudal and rotational movements. Patients favoured the more comfortable but less accurate neck support. To optimize the accuracy of SCRT, additional regular portal imaging is warranted.

Abstract P4-02-16: High miRNA26A1 and Low EZH2 Expression Levels Are Associated with Favorable Outcome to Tamoxifen in Advanced Breast Cancer through Similar Molecular Pathways

Background: We showed that decreased expression levels of EZH2 are associated with a favorable outcome to tamoxifen in advanced breast cancer. Furthermore, EZH2 knockdown in MCF7 cells resulted in estrogen receptor (ER) upregulation and increased sensitivity to anti-estrogens. Recently, EZH2 has been identified as a target of miRNA26A1 and miRNA101.

Objective: To associate miRNA26A1 and miRNA101 expression levels with: A) EZH2 and B) molecular pathways and C) outcome to first-line tamoxifen monotherapy for advanced disease.

Materials & Methods: Expression levels of miRNA26A1, miRNA101, EZH2 and references (miRNA-132 and miRNA-374) were measured using quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) in 235 ER-positive primary breast cancer specimens from patients with advanced disease. The levels of expression were related to clinicopathologic factors and disease outcome. Pathway analysis was performed in a subset of 65 ER-positive tumors with available gene expression microarray data available. Computations were performed with STATA and P-values &lt;0.05 were considered statistically significant.

Results: The miRNA26A1 levels were significantly associated with levels of ER, progesterone (PgR), HER2 and EGFR, whereas miRNA101 levels showed significant relations with PgR expression and menopausal status. The miRNA26A1 and miRNA101 levels showed an inverse relation with EZH2 mRNA levels (Spearman Rank Correlation of -0.21 and -0.15, respectively, P&lt;0.05). As continuous variable in univariate analysis, miRNA26A1 (Hazard Ratio (HR) =0.13, 95 % CI: 0.06-0.28) correlated with Time to Progression (TTP), while miRNA101 did not (HR=0.87, 95% CI: 0.70-1.07). In multivariate analysis including traditional predictive factors, the third with highest miRNA26A1 levels (HR=0.49, 95% CI: 0.34-0.72) alone, or combined with the third with lowest EZH2 levels (HR=0.56, 95% CI: 0.35-0.88) were associated with a favorable TTP independently of traditional factors. Pathway analyses identified 2 overlapping, cell cycle, related pathways with two genes (CCNE1and CDC2) differentially expressed (P&lt;0.05) between tumors with high and low levels of miRNA26A1 and EZH2, respectively. Levels of CCNE1 and CDC2 were tested in the 235 tumors and showed as continuous variables also a significant association with TTP (HR=1.27, 95% CI: 1.12-1.45 and HR=1.53, 95% CI: 0.129-1.81).

Conclusions: The miRNA26A1 and miRNA101 levels have an inverse relation with levels of EZH2, however, only miRNA26A1 has predictive value in advanced breast cancer. Pathways comparison between miRNA26A1 and EZH2 identified 2 overlapping cell cycle related pathways and the genes CCNE1 and CDC2. Low levels of EZH2, CCNE1 and CDC2 and high levels of miRNA26A1 are associated with a favorable outcome to tamoxifen therapy.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-02-16.

Complete response of a metastatic gastroesophageal adenocarcinoma on irinotecan-based chemotherapy in a dialysis patient

We present the first case report of a complete response of metastatic gastroesophageal cancer in a chronic hemodialysis patient with irinotecan-based chemotherapy. An elderly dialysis patient presented with diffuse liver metastases by a gastroesophageal adenocarcinoma. He received combination chemotherapy with 5 fluorouracil and irinotecan. After six months of chemotherapy, liver scans show complete remission. The principles, practice, and experience of chemotherapy with irinotecan during dialysis are discussed.