Elucidating molecular mechanisms of protoxin-II state-specific binding to the human NaV1.7 channel

Human voltage-gated sodium (hNaV) channels are responsible for initiating and propagating action potentials in excitable cells, and mutations have been associated with numerous cardiac and neurological disorders. hNaV1.7 channels are expressed in peripheral neurons and are promising targets for pain therapy. The tarantula venom peptide protoxin-II (PTx2) has high selectivity for hNaV1.7 and is a valuable scaffold for designing novel therapeutics to treat pain. Here, we used computational modeling to study the molecular mechanisms of the state-dependent binding of PTx2 to hNaV1.7 voltage-sensing domains (VSDs). Using Rosetta structural modeling methods, we constructed atomistic models of the hNaV1.7 VSD II and IV in the activated and deactivated states with docked PTx2. We then performed microsecond-long all-atom molecular dynamics (MD) simulations of the systems in hydrated lipid bilayers. Our simulations revealed that PTx2 binds most favorably to the deactivated VSD II and activated VSD IV. These state-specific interactions are mediated primarily by PTx2's residues R22, K26, K27, K28, and W30 with VSD and the surrounding membrane lipids. Our work revealed important protein-protein and protein-lipid contacts that contribute to high-affinity state-dependent toxin interaction with the channel. The workflow presented will prove useful for designing novel peptides with improved selectivity and potency for more effective and safe treatment of pain.

Elucidating Molecular Mechanisms of Protoxin-2 State-specific Binding to the Human NaV1.7 Channel

Human voltage-gated sodium (hNaV) channels are responsible for initiating and propagating action potentials in excitable cells and mutations have been associated with numerous cardiac and neurological disorders. hNaV1.7 channels are expressed in peripheral neurons and are promising targets for pain therapy. The tarantula venom peptide protoxin-2 (PTx2) has high selectivity for hNaV1.7 and serves as a valuable scaffold to design novel therapeutics to treat pain. Here, we used computational modeling to study the molecular mechanisms of the state-dependent binding of PTx2 to hNaV1.7 voltage-sensing domains (VSDs). Using Rosetta structural modeling methods, we constructed atomistic models of the hNaV1.7 VSD II and IV in the activated and deactivated states with docked PTx2. We then performed microsecond-long all-atom molecular dynamics (MD) simulations of the systems in hydrated lipid bilayers. Our simulations revealed that PTx2 binds most favorably to the deactivated VSD II and activated VSD IV. These state-specific interactions are mediated primarily by PTx2's residues R22, K26, K27, K28, and W30 with VSD as well as the surrounding membrane lipids. Our work revealed important protein-protein and protein-lipid contacts that contribute to high-affinity state-dependent toxin interaction with the channel. The workflow presented will prove useful for designing novel peptides with improved selectivity and potency for more effective and safe treatment of pain.

DeepWEST: Deep Learning of Kinetic Models with the Weighted Ensemble Simulation Toolkit for Enhanced Sampling

Recent advances in computational power and algorithms have enabled molecular dynamics (MD) simulations to reach greater time scales. However, for observing conformational transitions associated with biomolecular processes, MD simulations still have limitations. Several enhanced sampling techniques seek to address this challenge, including the weighted ensemble (WE) method, which samples transitions between metastable states using many weighted trajectories to estimate kinetic rate constants. However, initial sampling of the potential energy surface has a significant impact on the performance of WE, i.e., convergence and efficiency. We therefore introduce deep-learned kinetic modeling approaches that extract statistically relevant information from short MD trajectories to provide a well-sampled initial state distribution for WE simulations. This hybrid approach overcomes any statistical bias to the system, as it runs short unbiased MD trajectories and identifies meaningful metastable states of the system. It is shown to provide a more refined free energy landscape closer to the steady state that could efficiently sample kinetic properties such as rate constants.

#COVIDisAirborne: AI-enabled multiscale computational microscopy of delta SARS-CoV-2 in a respiratory aerosol

We seek to completely revise current models of airborne transmission of respiratory viruses by providing never-before-seen atomic-level views of the SARS-CoV-2 virus within a respiratory aerosol. Our work dramatically extends the capabilities of multiscale computational microscopy to address the significant gaps that exist in current experimental methods, which are limited in their ability to interrogate aerosols at the atomic/molecular level and thus obscure our understanding of airborne transmission. We demonstrate how our integrated data-driven platform provides a new way of exploring the composition, structure, and dynamics of aerosols and aerosolized viruses, while driving simulation method development along several important axes. We present a series of initial scientific discoveries for the SARS-CoV-2 Delta variant, noting that the full scientific impact of this work has yet to be realized.

Investigating Intrinsically Disordered Proteins With Brownian Dynamics

Intrinsically disordered proteins (IDPs) have recently become systems of great interest due to their involvement in modulating many biological processes and their aggregation being implicated in many diseases. Since IDPs do not have a stable, folded structure, however, they cannot be easily studied with experimental techniques. Hence, conducting a computational study of these systems can be helpful and be complementary with experimental work to elucidate their mechanisms. Thus, we have implemented the coarse-grained force field for proteins (COFFDROP) in Browndye 2.0 to study IDPs using Brownian dynamics (BD) simulations, which are often used to study large-scale motions with longer time scales and diffusion-limited molecular associations. Specifically, we have checked our COFFDROP implementation with eight naturally occurring IDPs and have investigated five (Glu-Lys)₂₅ IDP sequence variants. From measuring the hydrodynamic radii of eight naturally occurring IDPs, we found the ideal scaling factor of 0.786 for non-bonded interactions. We have also measured the entanglement indices (average C_α distances to the other chain) between two (Glu-Lys)₂₅ IDP sequence variants, a property related to molecular association. We found that entanglement indices decrease for all possible pairs at excess salt concentration, which is consistent with long-range interactions of these IDP sequence variants getting weaker at increasing salt concentration.

Gaussian-Accelerated Molecular Dynamics with the Weighted Ensemble Method: A Hybrid Method Improves Thermodynamic and Kinetic Sampling

Gaussian-accelerated molecular dynamics (GaMD) is a well-established enhanced sampling method for molecular dynamics simulations that effectively samples the potential energy landscape of the system by adding a boost potential, which smoothens the surface and lowers the energy barriers between states. GaMD is unable to give time-dependent properties such as kinetics directly. On the other hand, the weighted ensemble (WE) method can efficiently sample transitions between states with its many weighted trajectories, which directly yield rates and pathways. However, convergence to equilibrium conditions remains a challenge for the WE method. Hence, we have developed a hybrid method that combines the two methods, wherein GaMD is first used to sample the potential energy landscape of the system and WE is subsequently used to further sample the potential energy landscape and kinetic properties of interest. We show that the hybrid method can sample both thermodynamic and kinetic properties more accurately and quickly compared to using either method alone.

#COVIDisAirborne: AI-Enabled Multiscale Computational Microscopy of Delta SARS-CoV-2 in a Respiratory Aerosol

We seek to completely revise current models of airborne transmission of respiratory viruses by providing never-before-seen atomic-level views of the SARS-CoV-2 virus within a respiratory aerosol. Our work dramatically extends the capabilities of multiscale computational microscopy to address the significant gaps that exist in current experimental methods, which are limited in their ability to interrogate aerosols at the atomic/molecular level and thus ob-scure our understanding of airborne transmission. We demonstrate how our integrated data-driven platform provides a new way of exploring the composition, structure, and dynamics of aerosols and aerosolized viruses, while driving simulation method development along several important axes. We present a series of initial scientific discoveries for the SARS-CoV-2 Delta variant, noting that the full scientific impact of this work has yet to be realized.

ACM REFERENCE FORMAT

Abigail Dommer 1† , Lorenzo Casalino 1† , Fiona Kearns 1† , Mia Rosenfeld 1 , Nicholas Wauer 1 , Surl-Hee Ahn 1 , John Russo, 2 Sofia Oliveira 3 , Clare Morris 1 , AnthonyBogetti 4 , AndaTrifan 5,6 , Alexander Brace 5,7 , TerraSztain 1,8 , Austin Clyde 5,7 , Heng Ma 5 , Chakra Chennubhotla 4 , Hyungro Lee 9 , Matteo Turilli 9 , Syma Khalid 10 , Teresa Tamayo-Mendoza 11 , Matthew Welborn 11 , Anders Christensen 11 , Daniel G. A. Smith 11 , Zhuoran Qiao 12 , Sai Krishna Sirumalla 11 , Michael O'Connor 11 , Frederick Manby 11 , Anima Anandkumar 12,13 , David Hardy 6 , James Phillips 6 , Abraham Stern 13 , Josh Romero 13 , David Clark 13 , Mitchell Dorrell 14 , Tom Maiden 14 , Lei Huang 15 , John McCalpin 15 , Christo- pherWoods 3 , Alan Gray 13 , MattWilliams 3 , Bryan Barker 16 , HarindaRajapaksha 16 , Richard Pitts 16 , Tom Gibbs 13 , John Stone 6 , Daniel Zuckerman 2 *, Adrian Mulholland 3 *, Thomas MillerIII 11,12 *, ShantenuJha 9 *, Arvind Ramanathan 5 *, Lillian Chong 4 *, Rommie Amaro 1 *. 2021. #COVIDisAirborne: AI-Enabled Multiscale Computational Microscopy ofDeltaSARS-CoV-2 in a Respiratory Aerosol. In Supercomputing '21: International Conference for High Perfor-mance Computing, Networking, Storage, and Analysis . ACM, New York, NY, USA, 14 pages. https://doi.org/finalDOI.

Data for molecular dynamics simulations of Escherichia coli cytochrome bd oxidase with the Amber force field

Cytochrome bd-type quinol oxidase is an important metalloenzyme that allows many bacteria to survive in low oxygen conditions. Since bd oxidase is found in many prokaryotes but not in eukaryotes, it has emerged as a promising bacterial drug target. Examples of organisms containing bd oxidases include the Mycobacterium tuberculosis (Mtb) bacterium that causes tuberculosis (TB) in humans, the Vibrio cholerae bacterium that causes cholera, the Pseudomonas aeruginosa bacterium that contributes to antibiotic resistance and sepsis, and the Campylobacter jejuni bacterium that causes food poisoning. Escherichia coli (E. coli) is another organism exhibiting the cytochrome bd oxidase. Since it has the highest sequence identity to Mtb (36%) and we are ultimately interested in finding drug targets for TB, we have built parameters for the E. coli bd oxidase (Protein Data Bank ID number: 6RKO) that are compatible with the all-atom Amber ff14SB force field for molecular dynamics (MD) simulations. Specifically, we built parameters for the three heme cofactors present in all species of bacterial cytochrome bd-type oxidases (heme b558 , heme b595 , and heme d) along with their axial ligands. This data report includes the parameter and library files that can be used with Amber's LEaP program to generate input files for MD simulations using the Amber software package. We also provide the PDB data files of the initial model both by itself and solvated with TIP3P water molecules and counterions.

Short-term outcomes of a multicentre randomized clinical trial comparing laparoscopic pylorus-preserving gastrectomy with laparoscopic distal gastrectomy for gastric cancer (the KLASS-04 trial)

BACKGROUND

There remain concerns about the safety and functional benefit of laparoscopic pylorus-preserving gastrectomy (LPPG) compared with laparoscopic distal gastrectomy (LDG). This study evaluated short-term outcomes of a randomized clinical trial (RCT) comparing LPPG with LDG for gastric cancer.

METHODS

The Korean Laparoendoscopic Gastrointestinal Surgery Study (KLASS)-04 trial was an investigator-initiated, open-label, parallel-assigned, superiority, multicentre RCT in Korea. Patients with cT1N0M0 cancer located in the middle third of the stomach at least 5 cm from the pylorus were randomized to undergo LPPG or LDG. Participants, care givers and those assessing the outcomes were not blinded to group assignment. Outcomes were 30-day postoperative morbidity rate and death at 90 days.

RESULTS

Some 256 patients from nine institutions were randomized (LPPG 129 patients, LDG 127 patients) between July 2015 and July 2017 and outcomes for 253 patients were analysed. Postoperative complications within 30 days were seen in 19.3 and 15.5 per cent in the LPPG and LDG groups respectively (P = 0·419). Postoperative pyloric stenosis was observed in nine (7.2 per cent) and two (1·5 per cent) patients in the LPPG and LDG groups (P = 0·026) respectively. In multivariable analysis higher BMI was a risk factor for postoperative complications (odds ratio 1·17, 95 per cent c.i. 1·04 to 1·32; P = 0·011). Death at 90 days was zero in both groups.

CONCLUSION

Postoperative complications and mortality was comparable in patients undergoing LPPG and LDG. Registration number: NCT02595086 (http://www.clinicaltrials.gov).

AI-driven multiscale simulations illuminate mechanisms of SARS-CoV-2 spike dynamics

We develop a generalizable AI-driven workflow that leverages heterogeneous HPC resources to explore the time-dependent dynamics of molecular systems. We use this workflow to investigate the mechanisms of infectivity of the SARS-CoV-2 spike protein, the main viral infection machinery. Our workflow enables more efficient investigation of spike dynamics in a variety of complex environments, including within a complete SARS-CoV-2 viral envelope simulation, which contains 305 million atoms and shows strong scaling on ORNL Summit using NAMD. We present several novel scientific discoveries, including the elucidation of the spike's full glycan shield, the role of spike glycans in modulating the infectivity of the virus, and the characterization of the flexible interactions between the spike and the human ACE2 receptor. We also demonstrate how AI can accelerate conformational sampling across different systems and pave the way for the future application of such methods to additional studies in SARS-CoV-2 and other molecular systems.

A glycan gate controls opening of the SARS-CoV-2 spike protein

SARS-CoV-2 infection is controlled by the opening of the spike protein receptor binding domain (RBD), which transitions from a glycan-shielded 'down' to an exposed 'up' state to bind the human angiotensin-converting enzyme 2 receptor and infect cells. While snapshots of the 'up' and 'down' states have been obtained by cryo-electron microscopy and cryo-electron tomagraphy, details of the RBD-opening transition evade experimental characterization. Here over 130 µs of weighted ensemble simulations of the fully glycosylated spike ectodomain allow us to characterize more than 300 continuous, kinetically unbiased RBD-opening pathways. Together with ManifoldEM analysis of cryo-electron microscopy data and biolayer interferometry experiments, we reveal a gating role for the N-glycan at position N343, which facilitates RBD opening. Residues D405, R408 and D427 also participate. The atomic-level characterization of the glycosylated spike activation mechanism provided herein represents a landmark study for ensemble pathway simulations and offers a foundation for understanding the fundamental mechanisms of SARS-CoV-2 viral entry and infection.

A glycan gate controls opening of the SARS-CoV-2 spike protein

SARS-CoV-2 infection is controlled by the opening of the spike protein receptor binding domain (RBD), which transitions from a glycan-shielded "down" to an exposed "up" state in order to bind the human ACE2 receptor and infect cells. While snapshots of the "up" and "down" states have been obtained by cryoEM and cryoET, details of the RBD opening transition evade experimental characterization. Here, over 130 μs of weighted ensemble (WE) simulations of the fully glycosylated spike ectodomain allow us to characterize more than 300 continuous, kinetically unbiased RBD opening pathways. Together with ManifoldEM analysis of cryo-EM data and biolayer interferometry experiments, we reveal a gating role for the N-glycan at position N343, which facilitates RBD opening. Residues D405, R408, and D427 also participate. The atomic-level characterization of the glycosylated spike activation mechanism provided herein achieves a new high-water mark for ensemble pathway simulations and offers a foundation for understanding the fundamental mechanisms of SARS-CoV-2 viral entry and infection.

Enhanced wound healing using a 3D printed VEGF-mimicking peptide incorporated hydrogel patch in a pig model

There is a need for effective wound healing through rapid wound closure, reduction of scar formation, and acceleration of angiogenesis. Hydrogel is widely used in tissue engineering, but it is not an ideal solution because of its low vascularization capability and poor mechanical properties. In this study, gelatin methacrylate (GelMA) was tested as a viable option with tunable physical properties. GelMA hydrogel incorporating a vascular endothelial growth factor (VEGF) mimicking peptide was successfully printed using a three-dimensional (3D) bio-printer owing to the shear-thinning properties of hydrogel inks. The 3D structure of the hydrogel patch had high porosity and water absorption properties. Furthermore, the bioactive characterization was confirmed by cell culture with mouse fibroblasts cell lines (NIH 3T3) and human umbilical vein endothelial cells. VEGF peptide, which is slowly released from hydrogel patches, can promote cell viability, proliferation, and tubular structure formation. In addition, a pig skin wound model was used to evaluate the wound-healing efficacy of GelMA-VEGF hydrogel patches; the results suggest that the GelMA-VEGF hydrogel patch can be used for wound dressing.

Relationship Between Sexual Function and Pelvic Floor and Hip Muscle Strength in Women With Stress Urinary Incontinence

INTRODUCTION

The pelvic floor muscle (PFM) could affect female sexual functions. The hip muscles are morphologically and functionally linked to PFM and are important elements of female sexual attraction.

AIM

To determine the relationship between female sexual function and hip muscle strength and PFM functions in women with stress urinary incontinence (SUI).

METHODS

A total of 42 women with SUI were recruited in this study. Female sexual function was measured using the pelvic organ prolapse urinary incontinence sexual function questionnaire (PISQ). PFM functions were measured using a perineometer. Hip muscle strength was measured using a Smart KEMA tension sensor. The relationship between female sexual function and PFM function and hip muscle strength was assessed using Pearson correlation coefficients and multiple regression analyses with forward selection.

MAIN OUTCOME MEASURES

PISQ score, PFM functions (strength and endurance), and strength of hip extensor, abductor, and adductor were the main outcome measures.

RESULTS

For the behavioral/emotive domain in the PISQ, hip extensor strength (r = 0.452), PFM strength (r = 0.441), PFM endurance (r = 0.362), and hip adductor strength (r = 0.324) were significantly correlated and hip extensor strength emerged in multiple regression. For the physical domain in the PISQ, hip abductor strength (r = 0.417), PFM endurance (r = 0.356), hip adductor strength (r = 0.332), and PFM strength (r = 0.322) were significantly correlated and hip abductor strength entered in multiple regression. For partner-related domain in the PISQ, hip adductor (r = 0.386) and abductor strength (r = 0.314) were significantly correlated and hip adductor strength appeared in multiple regression. For the PISQ total score, hip extensor strength (r = 0.484), PFM endurance (r = 0.470), hip adductor strength (r = 0.424), hip abductor strength (r = 0.393), and PFM strength (r = 0.387) were significantly correlated and hip extensor strength and PFM endurance emerged in multiple regression.

CONCLUSION

The female sexual function could be related to not only PFM functions but also hip muscle strength in women with SUI. Hwang UJ, Lee MS, Jung SH, Ahn SH, Kwon OY. Relationship Between Sexual Function and Pelvic Floor and Hip Muscle Strength in Women With Stress Urinary Incontinence. Sex Med 2021;9:100325.

Ranking of Ligand Binding Kinetics Using a Weighted Ensemble Approach and Comparison with a Multiscale Milestoning Approach

To improve lead optimization efforts in finding the right ligand, pharmaceutical industries need to know the ligand's binding kinetics, such as binding and unbinding rate constants, which often correlate with the ligand's efficacy in vivo. To predict binding kinetics efficiently, enhanced sampling methods, such as milestoning and the weighted ensemble (WE) method, have been used in molecular dynamics (MD) simulations of these systems. However, a comparison of these enhanced sampling methods in ranking ligands has not been done. Hence, a WE approach called the concurrent adaptive sampling (CAS) algorithm that uses MD simulations was used to rank seven ligands for β-cyclodextrin, a system in which a multiscale milestoning approach called simulation enabled estimation of kinetic rates (SEEKR) was also used, which uses both MD and Brownian dynamics simulations. Overall, the CAS algorithm can successfully rank ligands using the unbinding rate constant k_off values and binding free energy ΔG values, as SEEKR did, with reduced computational cost that is about the same as SEEKR. We compare the CAS algorithm simulations with different parameters and discuss the impact of parameters in ranking ligands and obtaining rate constant and binding free energy estimates. We also discuss similarities and differences and advantages and disadvantages of SEEKR and the CAS algorithm for future use.

AI-Driven Multiscale Simulations Illuminate Mechanisms of SARS-CoV-2 Spike Dynamics

We develop a generalizable AI-driven workflow that leverages heterogeneous HPC resources to explore the time-dependent dynamics of molecular systems. We use this workflow to investigate the mechanisms of infectivity of the SARS-CoV-2 spike protein, the main viral infection machinery. Our workflow enables more efficient investigation of spike dynamics in a variety of complex environments, including within a complete SARS-CoV-2 viral envelope simulation, which contains 305 million atoms and shows strong scaling on ORNL Summit using NAMD. We present several novel scientific discoveries, including the elucidation of the spike's full glycan shield, the role of spike glycans in modulating the infectivity of the virus, and the characterization of the flexible interactions between the spike and the human ACE2 receptor. We also demonstrate how AI can accelerate conformational sampling across different systems and pave the way for the future application of such methods to additional studies in SARS-CoV-2 and other molecular systems.

Asymptomatic Cerebral Vasoconstriction after Carotid Artery Stenting

BACKGROUND AND PURPOSE

Carotid artery stent placement is widely performed for treatment of carotid stenosis. The purpose of this study is to present our observations on cerebral vasoconstriction in ipsilateral anterior circulation during immediate poststenting angiography in patients with near-total occlusion of the proximal ICA.

MATERIALS AND METHODS

We retrospectively reviewed patient data from December 2008 to December 2018. There were 28 patients with carotid near-total occlusion. Two neuroradiologists reviewed the final cerebral angiographic finding of carotid artery stent placement to evaluate the presence of vasoconstriction or vasodilation.

RESULTS

A total of 28 patients with near-total occlusion (mean ± standard deviation age, 69.0 ± 6.5 years; 92.9% male) were analyzed. Ten patients showed vasoconstriction in the treated territory, and 18 patients did not show vasoconstriction after carotid artery stenting. There were no statistically significant differences in comorbidity, frequency of symptomatic lesions, antiplatelet medication, mean procedure time, and initial NIHSS and baseline modified Rankin scale scores between the 2 groups. However, vasoconstriction is more likely to happen in patients with isolated territory from the contralateral anterior and posterior circulation (66.7% in the isolated territory group and 12.5% in the not-isolated territory group; P < .05). No headache or neurologic deficit was noted in all 10 patients with cerebral vasoconstriction.

CONCLUSIONS

Cerebral vasoconstriction may occur after carotid artery stenting more frequently than expected. It occurs more frequently in patients with near-total occlusion and with isolation of the cerebral circulation. A large-scale study is necessary to assess the clinical implications of cerebral vasoconstriction after carotid artery stenting.

Imaging Triage of Patients with Late-Window (6-24 Hours) Acute Ischemic Stroke: A Comparative Study Using Multiphase CT Angiography versus CT Perfusion

BACKGROUND AND PURPOSE

The role of collateral imaging in selecting patients for endovascular thrombectomy beyond 6 hours from onset has not been established. To assess the comparative utility of collateral imaging using multiphase CTA in selecting late window patients for EVT.

MATERIALS AND METHODS

We used data from a prospective multicenter observational study in which all patients underwent imaging with multiphase CT angiography as well as CTP. Two blinded reviewers evaluated patients' eligibility for endovascular thrombectomy using published collateral imaging (multiphase CTA) criteria compared with CTP using the selection criteria of the Clinical Mismatch in the Triage of Wake Up and Late Presenting Strokes Undergoing Neurointervention with Trevo (DAWN) and Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3 (DEFUSE-3) trials. CTP images were processed using automated commercial software. The outcomes of patients eligible for endovascular thrombectomy according to multiphase CTA, DAWN, or DEFUSE-3 criteria were compared using multivariable logistic regression modeling. Model characteristics were compared using the C-statistic for the receiver operating characteristic curve, the Akaike information criterion, and the Bayesian information criterion.

RESULTS

Eighty-six patients presented beyond 6 hours from onset/last known well (median, 9.6 hours; interquartile range, 4.1 hours). Thirty-five patients (40.7%) received endovascular thrombectomy, of whom good functional outcome (90-day mRS, 0-2) was achieved in 16/35 (47%). Collateral-based imaging paradigms significantly modified the treatment effect of endovascular thrombectomy on 90-day mRS 0-2 (P _interaction = .007). The multiphase CTA-based regression model best fit the data for the 90-day outcome (C-statistic, 0.86; 95% CI, 0.77-0.94) and was associated with the least information loss (Akaike information criterion, 95.7; Bayesian information criterion, 114.9) compared with CTP-based models.

CONCLUSIONS

The collateral-based imaging paradigm using multiphase CTA compares well with CTP in selecting patients for endovascular thrombectomy in the late time window.

Tamoxifen suppresses pancreatic β-cell proliferation in mice

Tamoxifen is a mixed agonist/antagonist estrogen analogue that is frequently used to induce conditional gene deletion in mice using Cre-loxP mediated gene recombination. Tamoxifen is routinely employed in extremely high-doses relative to typical human doses to induce efficient gene deletion in mice. Although tamoxifen has been widely assumed to have no influence upon β-cells, the acute developmental and functional consequences of high-dose tamoxifen upon glucose homeostasis and adult β-cells are largely unknown. We tested if tamoxifen influences glucose homeostasis in male mice of various genetic backgrounds. We then carried out detailed histomorphometry studies of mouse pancreata. We also performed gene expression studies with islets of tamoxifen-treated mice and controls. Tamoxifen had modest effects upon glucose homeostasis of mixed genetic background (F1 B6129SF1/J) mice, with fasting hyperglycemia and improved glucose tolerance but without overt effects on fed glucose levels or insulin sensitivity. Tamoxifen inhibited proliferation of β-cells in a dose-dependent manner, with dramatic reductions in β-cell turnover at the highest dose (decreased by 66%). In sharp contrast, tamoxifen did not reduce proliferation of pancreatic acinar cells. β-cell proliferation was unchanged by tamoxifen in 129S2 mice but was reduced in C57Bl6 genetic background mice (decreased by 59%). Gene expression studies revealed suppression of RNA for cyclins D1 and D2 within islets of tamoxifen-treated mice. Tamoxifen has a cytostatic effect on β-cells, independent of changes in glucose homeostasis, in mixed genetic background and also in C57Bl6 mice. Tamoxifen should be used judiciously to inducibly inactivate genes in studies of glucose homeostasis.

The multi-dimensional generalized Langevin equation for conformational motion of proteins

Using the generalized Langevin equation (GLE) is a promising approach to build coarse-grained (CG) models of molecular systems since the GLE model often leads to more accurate thermodynamic and kinetic predictions than Brownian dynamics or Langevin models by including a more sophisticated friction with memory. The GLE approach has been used for CG coordinates such as the center of mass of a group of atoms with pairwise decomposition and for a single CG coordinate. We present a GLE approach when CG coordinates are multiple generalized coordinates, defined, in general, as nonlinear functions of microscopic atomic coordinates. The CG model for multiple generalized coordinates is described by the multidimensional GLE from the Mori-Zwanzig formalism, which includes an exact memory matrix. We first present a method to compute the memory matrix in a multidimensional GLE using trajectories of a full system. Then, in order to reduce the computational cost of computing the multidimensional friction with memory, we introduce a method that maps the GLE to an extended Markovian system. In addition, we study the effect of using a nonconstant mass matrix in the CG model. In particular, we include mass-dependent terms in the mean force. We used the proposed CG model to describe the conformational motion of a solvated alanine dipeptide system, with two dihedral angles as the CG coordinates. We showed that the CG model can accurately reproduce two important kinetic quantities: the velocity autocorrelation function and the distribution of first passage times.

Association of blood n-3 fatty acid with bone mass and bone marrow TRAP-5b in the elderly with and without hip fracture

The plasma n-3 fatty acid level was 26.2% lower in patients with osteoporotic hip fracture than in those with osteoarthritis. In all patients, n-3 fatty acid was positively associated with bone mineral density and inversely associated with tartrate-resistant acid phosphatase-5b level in bone marrow aspirates, reflecting the bone microenvironment.

INTRODUCTION

Despite the potential beneficial role of n-3 fatty acid (FA) on bone metabolism, the specific mechanisms underlying these effects in humans remain unclear. Here, we assessed whether the plasma n-3 level, as an objective indicator of its status, is associated with osteoporosis-related phenotypes and bone-related markers in human bone marrow (BM) samples.

METHODS

This was a case-control and cross-sectional study conducted in a clinical unit. n-3 FA in the blood and bone biochemical markers in the BM aspirates were measured by gas chromatography/mass spectrometry and immunoassay, respectively. BM fluids were collected from 72 patients who underwent hip surgery because of either osteoporotic hip fracture (HF; n = 28) or osteoarthritis (n = 44).

RESULTS

After adjusting for confounders, patients with HF had 26.2% lower plasma n-3 levels than those with osteoarthritis (P = 0.006), and each standard deviation increment in plasma n-3 was associated with a multivariate-adjusted odds ratio of 0.40 for osteoporotic HF (P = 0.010). In multivariate analyses including all patients, a higher plasma n-3 level was associated with higher bone mass at the lumbar spine (β = 0.615, P = 0.002) and total femur (β = 0.244, P = 0.045). Interestingly, the plasma n-3 level was inversely associated with the tartrate-resistant acid phosphatase-5b level (β = - 0.633, P = 0.023), but not with the bone-specific alkaline phosphatase level, in BM aspirates.

CONCLUSIONS

These findings provide clinical evidence that n-3 FA is a potential inhibitor of osteoclastogenesis that favors human bone health.

The effects of cortisol and adrenal androgen on bone mass in Asians with and without subclinical hypercortisolism

Analyses using the largest Korean cohort of adrenal incidentaloma (AI) revealed that subtle cortisol excess in premenopausal women and reduced dehydroepiandrosterone-sulfate (DHEA-S) in postmenopausal women and men are associated with bone mineral density (BMD) reduction in Asian patients with subclinical hypercortisolism (SH).

INTRODUCTION

Few studies evaluated bone metabolism in Asians with SH. We investigated associations of cortisol and DHEA-S, an adrenal androgen, with BMD in Asians with AI, with or without SH.

METHODS

We used cross-sectional data of a prospective multicenter study from Korea. We measured BMD, bone turnover markers, cortisol levels after 1-mg dexamethasone suppression test (1-mg DST), DHEA-S, and baseline cortisol to DHEA-S ratio (cort/DHEA-S) in 109 AI patients with SH (18 premenopausal, 38 postmenopausal women, and 53 men) and 686 with non-functional AI (NFAI; 59 premenopausal, 199 postmenopausal women, and 428 men).

RESULTS

Pre- and postmenopausal women, but not men, with SH had lower BMDs at lumbar spine (LS) than those with NFAI (P = 0.008~0.016). Premenopausal women with SH also had lower BMDs at the hip than those with NFAI (P = 0.009~0.012). After adjusting for confounders, cortisol levels after 1-mg DST demonstrated inverse associations with BMDs at all skeletal sites only in premenopausal women (β = - 0.042~- 0.033, P = 0.019~0.040). DHEA-S had positive associations with LS BMD in postmenopausal women (β = 0.096, P = 0.001) and men (β = 0.029, P = 0.038). The cort/DHEA-S had inverse associations with LS BMD in postmenopausal women (β = - 0.081, P = 0.004) and men (β = - 0.029, P = 0.011). These inverse associations of cort/DHEA-S remained significant after adjusting for cortisol levels after 1-mg DST (β = - 0.079~- 0.026, P = 0.006~0.029). In postmenopausal women, the odds ratios of lower BMD by DHEA-S and cort/DHEA-S was 0.26 (95% CI, 0.08-0.82) and 3.40 (95% CI, 1.12-10.33), respectively.

CONCLUSION

Subtle cortisol excess in premenopausal women and reduced DHEA-S in postmenopausal women and men may contribute to BMD reduction in Asians with SH.

Clot Burden Score and Early Ischemia Predict Intracranial Hemorrhage following Endovascular Therapy

BACKGROUND AND PURPOSE

Intracranial hemorrhage is a known complication following endovascular thrombectomy. The radiologic characteristics of a CT scan may assist with hemorrhage risk stratification. We assessed the radiologic predictors of intracranial hemorrhage following endovascular therapy using data from the INTERRSeCT (Identifying New Approaches to Optimize Thrombus Characterization for Predicting Early Recanalization and Reperfusion With IV Alteplase and Other Treatments Using Serial CT Angiography) study.

MATERIALS AND METHODS

Patients undergoing endovascular therapy underwent baseline imaging, postprocedural angiography, and 24-hour follow-up imaging. The primary outcome was any intracranial hemorrhage observed on follow-up imaging. The secondary outcome was symptomatic hemorrhage. We assessed the relationship between hemorrhage occurrence and baseline patient characteristics, clinical course, and imaging factors: baseline ASPECTS, thrombus location, residual flow grade, collateralization, and clot burden score. Multivariable logistic regression with backward selection was used to adjust for relevant covariates.

RESULTS

Of the 199 enrolled patients who met the inclusion criteria, 46 (23%) had an intracranial hemorrhage at 24 hours. On multivariable analysis, postprocedural hemorrhage was associated with pretreatment ASPECTS (OR, 1.56 per point lost; 95% CI, 1.12-2.15), clot burden score (OR, 1.19 per point lost; 95% CI, 1.03-1.38), and ICA thrombus location (OR, 3.10; 95% CI, 1.07-8.91). In post hoc analysis, clot burden scores of ≤3 (sensitivity, 41%; specificity, 82%; OR, 3.12; 95% CI, 1.36-7.15) and pretreatment ASPECTS ≤ 7 (sensitivity, 48%; specificity, 82%; OR, 3.17; 95% CI, 1.35-7.45) robustly predicted hemorrhage. Residual flow grade and collateralization were not associated with hemorrhage occurrence. Symptomatic hemorrhage was observed in 4 patients.

CONCLUSIONS

Radiologic factors, early ischemia on CT, and increased CTA clot burden are associated with an increased risk of intracranial hemorrhage in patients undergoing endovascular therapy.

Abstract P3-13-01: Application of supine MRI-based 3D printing breast surgical guide for precision breast-conserving surgery

Background

If the size of the tumor is large, neoadjuvant systemic therapy (NST) is performed to reduce the size of the tumor and to conserve the breast. It is known that magnetic resonance imaging is more accurate than mammography (MMG) or ultrasonography (USG) in determining the area of residual cancer in breast-conserving surgery (BSG) after NST. However, there are some problems when performing BCS using MRI. Because the posture of MRI test is different from the posture at surgery, it is difficult to accurately mark the area of the tumor observed in MRI. Neoadjuvant systemic therapy reduces tumor size and often makes it difficult to detect the original tumor area on preoperative MRI. Even if the tumor is not visible in the image, the cancer cells may remain, so it is important to accurately indicate the extent of the initial tumor and remove it. Until now, however, there has been no way to accurately mark past breast tumors in the breast. We have developed a breast surgical guide (BSG) that can mark a range of tumor directly on the breast using three-dimensional printing technology based on supine MRI. This study analyzed the results of patients who underwent BCS using a 3D printing breast surgical guide (3D-BSG) based on supine MRI.

Methods

This trial was designed as a prospective single-institution cohort study. Our study protocol was approved by the Institutional Review Board of Asan Medical Center, Seoul, Korea (IRB No. 2016-1237). Patients who were expected to undergo BCS after NST were enrolled in this study and supine MRI was performed before and after NST. From MRI images, morphological shapes of breasts and tumors were modeled. The prepared digital model was saved in stereolithography file format and then exported to a 3D printer. 3D-BSG is designed to be able to mark the skin and attach the dye injecting column to mark the around the tumor. The breast tissue was removed with blue dye on the basis of the border. To obtain tumor free margin, intraoperative frozen sections were identified in several cavities and re-excision was performed if tumor positive.

Results

Between January 2016 and May 2017, 50 patients were enrolled in the study. BCS was applied to 40 patients, except for those who were rejected or mastectomy. Complete remission was observed in 15 patients after NST. Four patients had tumor positive on resection margins on frozen biopsy during operation, two with IDC and two with DCIS. Re-excision was performed in these patients and tumor negative margin was confirmed in all patients in the final pathology results. The median size of the long axis of the tumor was 1.7 cm (range, 0.5 to 4.5 cm) and the median size of the long axis of the removed breast tissue was 5.1 cm (range, 2.3 to 8.1 cm). The distance between tumor and resection margin was 1.2 cm (range, 0.1 to 4.8 cm)..

Conclusions

In BCS, the application of the supine MRI based 3D-BSG showed low rates of positive margins. Unlike conventional localization techniques, application of 3D-BSG does not cause pain to the patient, has no radiation exposure, and has no time required for the localization procedure, so it will be helpful for patients in BCS in the future.

Citation Format: Ko B, Kim N, Seo J, Kim H, Gong G, Kim S, Son B, Ahn SH. Application of supine MRI-based 3D printing breast surgical guide for precision breast-conserving surgery [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 P3-13-01.

Abstract P2-14-21: Not presented

This abstract was not presented at the conference.

Citation Format: Lee S, Ahn SH, Lee JW, Chung IY, Ko BS, Kim HJ, Kim J, Shon G, Son BH. Not presented [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 P2-14-21.

Abstract P6-09-09: Analysis of serial circulating tumor cell count during neoadjuvant systemic therapy in breast cancer patients

Background: We aimed to evaluate the clinical implication of circulating tumor cell (CTC) counts in correlation with prognosis and radiologic/pathologic response to therapy in locally advanced breast cancer patients undergoing preoperative systemic therapy.

Methods: From Feb 2014 to May 2017, 207 patients without distant metastasis were prospectively enrolled from AMC. CTC counts were analyzed before-during-after the therapy. CTC isolation was performed using a SMART BIOPSY™ SYSTEM Isolation kit (Cytogen, Inc., Seoul, Korea). Recurrence-free and overall survival was analyzed according to CTC counts.

Result: The mean follow-up period was 22.46 months and mean age was 46.48 years. One or more CTC was identified in 132 of 203 patients(65.0%) before NST, in 135 of 186 patients(72.0%) during NST and 103 of 171 patients(60.2%) after NST. Initial tumor burden at diagnosis -tumor size, lymph node metastasis- was not correlated with CTC positivity. Overall, CTC count ((≥1 CTC, ≥2 CTCs, and ≥5 CTCs) was not correlated with response to therapy. Using RECIST criteria, 86.5% (179/204) were responders (complete, partial response, CR/PR) and 12.1% (25/204) were non-responders (stable, progressive disease, SD/PD). 14.5% (30/207) showed a pathologic complete response (pCR), yet no association was found between CTC count/changes and radiologic/pathologic response to therapy. Also, CTC count was not correlated with prognosis among the whole population. However, HR+ tumors, CTC detection before NST was significantly associated with treatment response by RECIST criteria (responder vs. non-responder) (p=0.003, p=0.017 and p=0.023, respectively).

Conclusions: Our findings support limited value of CTC count for locally advanced breast cancers undergoing neoadjuvant systemic therapy.

Citation Format: Gwark S-C, Kim J, Kim YH, Kim MS, Park JY, Lee SB, Sohn G, Chung IY, Ko BS, Kim HJ, Lee JW, Son BH, Ahn SH. Analysis of serial circulating tumor cell count during neoadjuvant systemic therapy in breast cancer patients [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 P6-09-09.

Abstract P1-02-04: Is asymptomatic surveillance after standard treatment beneficial? : A 10yr-survival analysis of recurrent breast cancer patients by detection method of recurrence

Surveillance of recurrence after standard treatment of breast cancer (BC) for early detection and it's impact on overall survival are known to differ depending on recurrent site. Current guideline recommends asymptomatic surveillance to only detect loco-regional recurrences. As the evidences depend on historical randomized clinical trials we aimed to address questions whether earlier detection might have impact on survival now that plenty of new treatment strategies can be offered. Also to give answers to heterogeneous surveillance strategy in real-world practice we performed a retrospective 10yr-survival analysis of a large cohort of recurrent BC patients according to their detection method.

From 4188 operable breast cancer patients who completed standard treatment Asan Medical Center from 2006 to 2008 469 patients with recurrent BC were analyzed. Median disease free interval was 35.3 months (range 2.8-97.6) and overall survival (OS) was analyzed as time from initial diagnosis/surgery to death. Among 469 patients who developed recurrence 23.7% were local (ipsilateral breast skin chest wall) 22.6% were regional (ipsilateral axillary internal mammary lymph nodes) and 53.7% developed distant metastasis. 10yr-overall survival was analyzed according to recurrent site and it's detection method.

Detection of recurrence were categorized as 'asymptomatic surveillance (N=162, 34.5%)' and 'symptom-guided (N=307, 65.5%)'. Asymptomatic screening method included mammography breast-ultrasound serum tumor marker (CA15-3) and systemic images (eg. chest X-ray bone scan PET scans). Symptom-guided detection rate for local regional and distant metastasis was 14.9%, 5.5% and 15.1% respectively. Overall asymptomatic vs symptomatic 10yr-OS did not differ (81.3 vs 78.8 months, p=0.778). Among patients with distant metastasis 10ys-OS was not significantly different (70.3 vs 66.7 months p=0.846) and was similar according to stage/subtype. Among patients with local recurrence only 10yr-OS was 95.1 months ('symptomatic' vs 'aymptomatic 94.4 vs 94.5, p=0.809) which may be insufficient number of events to show significant difference. Among regional recurrent BCs, longer OS was observed in asymptomatically detected patients than symptom-guided group (86.1 vs 63.4, p=0.004). In Cox regression analyses asymptomatic detection showed significant better survival (HR=3.9, 95%CI:1.6-9.5) and this observation was more evident in patients with hormone receptor(HR) negative primary BCs (69.9 vs 47.9, p=0.029). Intriguingly, only 8.6% (7/80) of regional recurrence were diagnosed by mammography.

We observed survival benefit with asymptomatic screening in detecting regional recurrence especially in HR-negative primary BC patients. And role of systemic radiology even in advanced high risk breast cancer patients were limited. Although with limitation that surveillance method varied widely we emphasize the role of aymptomatic surveillance of regional nodal evaluation including breast-ultrasound. These findings are to be validated from a prospective clinical study along with using cutting edge modalities other than radiology which enable detection of micro-metastasis.

Citation Format: Lee Y, Lee HS, Ahn SH, Son BH, Kim J, Lee SB. Is asymptomatic surveillance after standard treatment beneficial? : A 10yr-survival analysis of recurrent breast cancer patients by detection method of recurrence [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-02-04.

Abstract P2-08-22: Clinical implication of HER2/neu status in hormone receptor positive pure mucinous breast cancer

Background: Mucinous carcinoma of the breast is a rare type of breast cancer with favorable outcome compared with other types of breast cancer. The current guideline does not recommend chemotherapy/anti-HER2 therapy for mucinous breast cancer with hormone receptor-positive subtype regardless of HER2/neu status. In this study, we evaluated the survival of pure mucinous breast cancer according to tumor stage and subtype.

Methods: Between 1989 and 2014, in Asan Medical Center, Korea, total 473 pure mucinous carcinomas (stage I-III) undergone curative surgery were reviewed retrospectively. 5yr disease-free and overall survival were analyzed according to size, lymph node metastasis, hormone receptor/HER2 status and given therapy.

Result: Total of 473 patients with pure mucinous breast cancer were analyzed and median follow-up duration was 78.00 months. 439 patients were hormone receptor-positive, 374 were node negative, 55 were HER2/neu positive. Among 374 patients with hormone receptor-positive and node-negative, tumor size was &lt;1cm in 46 patients, 1-2.9cm in 259 patients, ≥3cm in 69 patients. In HR-positive/Node-positive BCs, 90.8%(59/65)were given chemotherapy and 35.3%(6/17) were also given trastuzumab. Sixteen patients given trastuzumab were only included in the analysis to assess the benefit of trastuzumab among HER2 positive BCs.

Overall, 5-year disease-free survival (DFS) rate was 94.1% and the 5-year overall survival (OS) rate was 95.9%. Using Cox regression analysis, lymph node metastasis was the only significant prognostic factor for both DFS (HR4.0, 95%CI:1.8-9.0, p=0.001) and OS (HR3.5, 95%CI:1.3-8.9, p=0.008). Among HR-positive/node-negative with tumor size ≥3cm, HER2/neu positivity was only significantly associated with 5yr-DFS (71.4% in HER2/neu+ vs. 96.4% in HER2/neu-, HR9.5, 95%CI:1.3-67.5, p=0.024). This observation was consistently combining both 'HR-positive/node-negative/&gt;3cm' and 'HR-positive/node positive' BCs (N=127) that HER2 positive tumors showed worse survival (HR 3.7, 95%CI:1.2-10.8, p=0.015). Intriguingly, within this subgroup of HR-positive/node-negative/&gt;3cm' and 'HR-positive/node positive' BCs, among HER2 positive tumors, while 5yr-DFS was 63.7% in patients who didn't receive trastuzumab, 100% were disease free in patients who were given trastuzumab.

Conclusions: Overall, nodal status was the most significant prognostic factor for pure mucinous breast cancer. In hormone receptor-positive, lymph node negative mucinous breast cancer with tumor of ≥3cm, HER2 positive BCs showed worse survival, suggesting a potential role of anti-HER2 strategy in this subgroup.

Citation Format: Gwark S-C, Lee JW, Lee SB, Sohn G, Kim J, Chung IY, Ko BS, Kim HJ, Son BH, Ahn SH. Clinical implication of HER2/neu status in hormone receptor positive pure mucinous 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 P2-08-22.

Abstract P4-01-11: Genomic alterations of cell-free DNA in early breast cancer patients with recurrence

Cell-free DNA (cfDNA), as a non-invasive strategy, provides substantial benefit to overcome tumor heterogeneity. Surveillance of recurrence after standard treatment in early breast cancer (BC) using cfDNA, enables to detect minimal residual disease (MRD), also to identify genomic alterations driving recurrences. We aimed to assess the role of cfDNA in detecting MRD by investigating genomic alterations of 1)primary, recurred tumor and 2)cfDNA at time of recurrence using deep targeted sequencing. Fifty-four early BC patients were enrolled prospectively between 2014 and 2017 at time of recurrence. Median disease free interval was 28.5 months (rage 6.2-49.8). 62.7% (32/51) were hormone receptor (HR) positive (28 HRpos/HER2neg, 4 HRpos/HER2pos), 11.8% (6/51) were HRneg/HER2pos and 25.5% (13/51) were triple negative BCs. 59.3% (32/54) patients developed loco-regional recurrence (15 local recurrence only, 13 regional only, 4 with both) and distant metastasis was observed among 40.7% (22/54) patients. Cell-free DNA was extracted from 5cc blood at time of recurrence. Deep targeted sequencing was performed using customized NGS panel –encompassing 426 cancer-related target coding region, 242 fusion and amplification-related region- of cfDNA and FFPE(formalin fixed paraffin embedded) tumor samples archived from surgical resection or biopsy. Deep targeted sequencing data was successfully performed in 72.1% (31/43) plasma samples and sequencing yield was significantly lower when stored for more than 2yrs (46.2% vs 83.3%).

Mutations of cfDNA and tumor (primary, recurred) were analyzed. Mean sequencing depth of cfDNA and FFPE were x425.7 and x777.6 respectively. Median number of pathogenic mutations found in primary tumor, cfDNA and recurred tumor were 27(range 12-99), 25(range 8-85) and 9(range 0-23). Among mutations found in primary tumor, 27.4% were shared mutations (range 8.1%-72.7%) with recurred tumor and 26.1% were shared mutations (range 4.7%-69.2%) observed in cfDNA sample. Among mutations found in recurred tumor, 40.9% were observed in cfDNA (range 17.7-87.5%). In primary tumor, median number of mutations with allelic fraction (MAF)&gt;10% were 12 (range 4-21) and at least one mutation was found in cfDNA at time of recurrence. Among mutations with MAF&gt;10%, 59.4% and 69.1% were found in cfDNA and recurred tumor. Known oncogenic mutations of PIK3CA, TP53, GATA3, AKT1, ESR1, RELN, ERBB2, ERBB3, BRCA1 mutation were found. PIK3CA gene (p.H1047R) was found in two cases both in primary tumor and cfDNA at recurrence (MAF 11.4% vs 5.3% and 12.3% vs 15.4%) suggesting de novo driver mutation. One patient developed regional recurrence during adjuvant aromatase inhibitor with ESR1 V392I mutation in both cfDNA and recurred tumor (MAF 48.1 and 54.5%), while another patient's recurred tumor during aromatase inhibitor harbored ESR1 D538G mutation exclusively in recurred tumor with MAF &lt;1%. Both patients had no ESR1 hotpot mutation in primary tumor.

Our data showed sequencing yield of 83.3% in plasma samples within 2yr. Pathogenic mutations in primary tumor, especially when MAF&gt;10%, half of them was observed in cfDNA at time of recurrence. ESR1 mutation should be included in cfDNA surveillance for patients undergoing endocrine therapy even absent in primary tumor.

Citation Format: Kim J, Jo WK, Kim KY, Kim BJ, Lee SB, Lee HJ, Yu JH, Kim HJ, Chung IY, Ko BS, Kim S-B, Jung KH, Ahn JH, Chang S, Lee JW, Son BH, Ahn SH. Genomic alterations of cell-free DNA in early breast cancer patients with recurrence [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-01-11.

Abstract P4-14-04: Time course changes in serum FSH, estradiol, and menstruation restoration in premenopausal patients with breast cancer taking adjuvant tamoxifen after completing chemotherapy: A report from the ASTRRA study

BACKGROUND

Assessment of restoration of ovarian function after chemotherapy is critical with respect to the initiation of different types of endocrine treatment in young high risk breast cancer patients

METHODS

In total, 1289 women who remained premenopausal or resumed premenopausal status after chemotherapy were randomized to receive 5 years of tamoxifen or 5 years of tamoxifen plus 2 years of ovarian suppression. The patients who did not resume menstruation were followed up for 2 years with tamoxifen treatment after finishing chemotherapy. Prospectively collected consecutive post-chemotherapy hormone and menstruation data were available for 705 breast cancer patients who enrolled tamoxifen-only treatment group or did not resume menstruation during follow up. This analysis evaluated the proportion of patients with pre-menopausal FSH levels (&lt;30 mIU/ml), E2 levels (340 pg/ml), and menstruation at any time point during treatment with tamoxifen.

RESULTS

During 5 years of tamoxifen treatment after chemotherapy for premenopausal breast cancer patients, 62% of patients resumed menstruation. Menstruation returned in 92% of patients under 35 years old but only in 31% of patients over 45 years old. Ovarian function, defined by serum FSH and E2 levels, resumed in 94% and 65% of patients, respectively, over 5 years. Most patients achieved ovarian function restoration during the first 2 years after chemotherapy, with 47.1% resuming menstruation and 86.2% and 50.3% achieving pre-menopausal FSH and E2 levels, respectively, in the first 2 years. Clinical factors related to menstruation restoration were younger age (HR = 6.38, 95% CI 1.33-3.47), 6 month hormone profile after chemotherapy (FSH&lt;30: HR=1.67, 95% CI 1.28-2.17; E2 &gt;40: HR=2.96, 95% CI 2.25-3.89), and anthracycline without taxane chemotherapy (HR=1.63, 95% CI 1.25-2.13).

CONCLUSIONS

During 5 years of tamoxifen treatment after chemotherapy, half of patients experienced menstruation restoration, including most very young patients under 35 years. The majority of patients experienced menstruation restoration in the first 2 years of tamoxifen treatment.

Citation Format: Kim HJ, Noh WC, Nam SJ, Park B-w, Lee ES, Im SA, Jung YS, Yoon JH, Kang SS, Park KH, Lee S-J, Jung J, Lee MH, Cho SH, Kim SY, Kim H-A, Han S-H, Han W, Hur MH, Ahn SH. Time course changes in serum FSH, estradiol, and menstruation restoration in premenopausal patients with breast cancer taking adjuvant tamoxifen after completing chemotherapy: A report from the ASTRRA study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-14-04.

Abstract P2-08-60: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Lee S, Ahn SH, Son BH, Lee JW, Chung IY, Ko BS, Kim HJ, Kim J, Shon G. Withdrawn [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 P2-08-60.

Safety and efficacy of vesatolimod (GS-9620) in patients with chronic hepatitis B who are not currently on antiviral treatment

Vesatolimod is an oral agonist of toll-like receptor 7 designed to minimize systemic exposure and side effects. We assessed the safety and efficacy of vesatolimod in viremic chronic hepatitis B (CHB) patients not currently on oral antiviral treatment (OAV) in a phase 2, multicentre, double-blind, randomized, placebo-controlled study. A total of 192 patients stratified by HBeAg status and alanine aminotransferase level were randomized 2:2:2:1 to receive oral vesatolimod (1-, 2- or 4-mg) or placebo once weekly for 12 weeks; tenofovir disoproxil fumarate (300-mg daily) was administered daily for 48 weeks. Efficacy was assessed by quantitative serum HBsAg decline at Week 24 from baseline. In addition to safety assessments, changes in whole-blood interferon-stimulated gene (ISG) transcripts and serum cytokines were explored. Most patients were male (64.1%) and HBeAg-negative (60.9%) at baseline. Among vesatolimod-treated patients, most (60.4%-69.1%) experienced ≥1 treatment-emergent adverse event; the majority were mild or moderate in severity. No clinically meaningful differences in HBsAg changes from baseline were observed between treatment groups. No patients experienced HBsAg loss, while 3 patients experienced HBeAg loss and hepatitis B e-antibody seroconversion at week 48. HBV DNA suppression rates were similar across all treatment arms at Week 24. ISG15 induction was dose-dependent and did not correlate with HBsAg changes. A small proportion of patients exhibited dose-dependent interferon-α induction that correlated with grade of influenza-like adverse events. Overall, vesatolimod is safe and well tolerated in CHB patients. Although consistent dose-dependent pharmacodynamic induction of ISGs was demonstrated, it did not result in clinically significant HBsAg decline.

Evolution and persistence of resistance-associated substitutions of hepatitis C virus after direct-acting antiviral treatment failures

Daclatasvir plus asunaprevir (DCV+ASV) treatment is an all-oral direct-acting antiviral (DAA) therapy for the genotype 1b HCV-infected patients. In this study, we investigated how resistance-associated substitutions (RASs) evolved after treatment failures and assessed the effect of those substitutions on viral fitness. Sequencing of NS5A and NS3 revealed typical RASs after treatment failures. Interestingly, the RASs of NS3 reverted to the wild-type amino acid within 1 year after treatment failures. However, the RASs of NS5A were stable and did not change. The effect of NS5A and NS3 RASs on viral RNA replication was assessed after mutagenic substitution in the genotype 1b HCV RNA. Among single substitutions, the effect of D168V was more substantial than the others and the effect of the triple mutant combination (D168V+L31V+Y93H) was the most severe. The RAS at NS5A Y93 affected both viral RNA replication and virus production. Finally, the effect of trans-complementation of NS5A was demonstrated in our co-transfection experiments and these results suggest that such a trans-complementation effect of NS5A may help maintain the NS5A RASs for a long time even after cessation of the DAA treatment. In conclusion, the results from this investigation would help understand the emergence and persistence of RASs.

The association of cortisol and adrenal androgen with trabecular bone score in patients with adrenal incidentaloma with and without autonomous cortisol secretion

Despite ethnic differences in cortisol sensitivity, only one study in Caucasians has assessed trabecular bone score (TBS) in patients with subclinical hypercortisolism (SH). We showed that both subtle cortisol excess and reduced adrenal androgen may contribute to impaired bone quality in Asian women with SH.

INTRODUCTION

One study in Caucasians has assessed trabecular bone score (TBS), an index of bone microstructure, in adrenal incidentaloma (AI) patients with subclinical hypercortisolism (SH). There are ethnic differences in cortisol sensitivities between Caucasian and Asian populations. We investigated the associations of cortisol and the adrenal androgen dehydroepiandrosterone-sulfate (DHEA-S) with TBS in AI patients with SH, adrenal Cushing's syndrome (CS), and nonfunctional AI (NFAI).

METHODS

We measured TBS, cortisol levels after the overnight 1 mg dexamethasone suppression test (1 mg DST), and cortisol/DHEA-S in 61 patients with SH (30 men; 31 women), 19 with adrenal CS (4 men; 15 women), and 355 with NFAI (213 men; 142 women).

RESULTS

After adjusting for confounders, the serum cortisol level after 1 mg DST was inversely correlated with TBS in men (β = -0.133, P = 0.045) and women (β = - 0.140, P = 0.048). Higher cortisol/DHEA-S ratio was associated with lower TBS in women (β = - 0.252, P < 0.001), but not men. This inverse association of cortisol/DHEA-S ratio in women remained statistically significant after adjusting for the serum cortisol level after 1 mg DST (β = - 0.221, P = 0.008). Compared with women with NFAI, women with SH had 2.2% lower TBS (P = 0.040). Deteriorated bone microstructure (TBS < 1.230) was associated with the serum cortisol level after 1 mg DST (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.04-4.53) and cortisol/DHEA-S ratio (OR, 2.05; 95% CI, 1.03-4.08).

CONCLUSIONS

Subtle cortisol excess in both genders and reduced DHEA-S, especially in women, may contribute to impaired bone quality in Asian patients with SH.

Sarcopenia is associated with the risk of significant liver fibrosis in metabolically unhealthy subjects with chronic hepatitis B

BACKGROUND

Sarcopenia is significantly associated with the degree of liver fibrosis. This study investigated the influence of sarcopenia on liver fibrosis in individuals with chronic hepatitis B.

METHODS

Data from the Korean National Health and Nutrition Examination Surveys 2008-2011 were analysed. The sarcopenia index (total appendicular skeletal muscle mass [kg]/body mass index [kg/m² ]) was calculated using dual-energy X-ray absorptiometry. Sarcopenia was defined as the lowest quintile sarcopenia index value (cut-offs: 0.89 for men and 0.58 for women). The fibrotic burden was assessed using the nonalcoholic fatty liver disease fibrosis score and fibrosis-4 index. Significant fibrosis was defined as the highest nonalcoholic fatty liver disease fibrosis score quartile and a fibrosis-4 index ≥2.67.

RESULTS

Among the 506 respondents with chronic hepatitis B (258 men and 248 women), the nonalcoholic fatty liver disease fibrosis score and fibrosis-4 index identified sarcopenia and significant fibrosis in 126 (24.9%) and 217 (42.9%), respectively. Sarcopenia was significantly associated with significant fibrosis, regardless of the fibrosis prediction model used (all P < 0.05). When the study population was stratified according to metabolic factors, sarcopenia was specifically associated with an increased risk of significant fibrosis among subgroups with obesity, insulin resistance, metabolic syndrome and liver steatosis (odds ratio 2.37-3.57; all P < 0.05). An independent association between sarcopenia and significant fibrosis was identified after adjusting for other confounders (odds ratio 2.67-3.62 by the nonalcoholic fatty liver disease fibrosis score and 2.04-2.62 by the fibrosis-4 index; all P < 0.05).

CONCLUSIONS

Sarcopenia is associated with significant fibrosis in subjects with chronic hepatitis B, specifically those with obesity, insulin resistance, metabolic syndrome and liver steatosis.

Efficiently sampling conformations and pathways using the concurrent adaptive sampling (CAS) algorithm

Molecular dynamics simulations are useful in obtaining thermodynamic and kinetic properties of bio-molecules, but they are limited by the time scale barrier. That is, we may not obtain properties' efficiently because we need to run microseconds or longer simulations using femtosecond time steps. To overcome this time scale barrier, we can use the weighted ensemble (WE) method, a powerful enhanced sampling method that efficiently samples thermodynamic and kinetic properties. However, the WE method requires an appropriate partitioning of phase space into discrete macrostates, which can be problematic when we have a high-dimensional collective space or when little is known a priori about the molecular system. Hence, we developed a new WE-based method, called the "Concurrent Adaptive Sampling (CAS) algorithm," to tackle these issues. The CAS algorithm is not constrained to use only one or two collective variables, unlike most reaction coordinate-dependent methods. Instead, it can use a large number of collective variables and adaptive macrostates to enhance the sampling in the high-dimensional space. This is especially useful for systems in which we do not know what the right reaction coordinates are, in which case we can use many collective variables to sample conformations and pathways. In addition, a clustering technique based on the committor function is used to accelerate sampling the slowest process in the molecular system. In this paper, we introduce the new method and show results from two-dimensional models and bio-molecules, specifically penta-alanine and a triazine trimer.

Predictors of failure to detect early hepatocellular carcinoma in patients with chronic hepatitis B who received regular surveillance

BACKGROUND

A proportion of chronic hepatitis B (CHB) patients are diagnosed with advanced hepatocellular carcinoma (HCC) despite regular surveillance.

AIMS

To determine predictors for HCC detection failure in CHB patients who underwent regular surveillance.

METHODS

CHB patients with well-preserved liver function, who underwent ultrasonography and alpha-foetoprotein (AFP) analysis every 6 months, were enrolled. Cox regression analysis was used to identify predictors for detection failure, defined as HCC initially diagnosed at Barcelona Clinic Liver Cancer (BCLC) stage B or C.

RESULTS

Of the 4590 CHB patients (mean age, 52.1 years; men, 61.6%), 169 patients were diagnosed with HCC (3.68%) and 35 (20.7%) HCC patients were initially diagnosed with HCC BCLC stage B or C. The cumulative incidence of HCC detection failure was 0.2% at year 1 and 1.3% at year 5. Multivariate analyses indicated that cirrhosis (hazard ratio [HR], 3.078; 95% CI, 1.389-6.821; P = 0.006), AFP levels ≥9 ng/mL (HR, 5.235; 95% CI, 2.307-11.957; P = 0.010), and diabetes mellitus (HR, 3.336; 95% CI, 1.341-8.296; P = 0.010) were independent predictors of HCC detection failure. Another model that incorporated liver stiffness (LS) values identified LS values ≥11.7 kPa (HR, 11.045; 95% CI, 2.066-59.037; P = 0.005) and AFP levels ≥9 ng/mL (HR, 4.802; 95% CI, 1.613-14.297; P = 0.005) as predictors of detection failure.

CONCLUSIONS

In CHB patients undergoing regular surveillance with ultrasonography and alpha-foetoprotein (AFP) analysis every 6 months, the HCC detection failure rate was not high (0.8% per person; 0.1% per test). However, careful attention should be paid in patients with advanced liver fibrosis (clinical cirrhosis or LS value >11.7 kPa), high AFP levels, or diabetes mellitus, who are prone to surveillance failure.

Abstract P1-07-29: Clinicopathologic characteristics and prognostic factors of pure mucinous breast cancer

Background: Mucinous carcinoma of the breast is a uncommon particular type of breast cancer and comprises approximately 4% of all invasive breast cancers. It is charactarized by abundant extracellular mucin production and present a more favorable prognosis than IDC-NOS. Pathologically, mucinous carcinoma is divided into two subtypes : pure and mixed. In this study, we reviewed the clinicopathologic characteristics and prognostic factors of pure mucinous carcinoma.

Methods: We reviewed the 23 years cumulative data of pure mucinous breast cancer patients from database of the Breast Cancer Center at ASAN medical center, Korea, between 1989-2011, retrospectively. Total 386 pure mucinous carcinoma cases were reviewed to analyze clinicopathologic characteristics and prognosis.

Result: Total of 386 patients with pure mucinous breast cancer were identified. Mean age was 46.7. 149 patients underwent modified radical mastectomy and 236 underwent breast-conserving therapy. The T-stage was T1 in 187 patients, T2 in 178 patients, T3 in 17 patient and T4 in 4 patients. Node negative was 325 and node positive was 61. Estrogen receptor was positive in 342 and negative in 29. Progesterone receptor was positive in 276 and negative in 95. HER-2 was positive in 47 and negative in 273. 152 patients received adjuvant chemotherapy and 240 patients received adjuvant radiotherapy. 351 patients received hormone therapy and among these patients, 231 patients were treated with Tamoxifen alone, 81 were Tamoxifen with ovarian function suppression, 37 were AI only and one patient was ovarian function suppression only. The 5 year disease free survival rate was 93.3%, 5 year cancer specific survival rate was 98.2% and 5 year overall survival rate was 96.6%. Univariate analysis showed that ER status, nodal status and Her2 status were appear to be prognostic factor of Disease free survival rate. Using Cox regression, result of multivariate analysis revealed that only nodal status is the most significant prognostic factor for survival rate.

Conclusions: Pure mucinous carcinoma of the breast is a rare subtype with a favorable prognosis. Nodal status rather than ER status, Her2 status are considered to be the most significant prognostic factor of pure mucinos breast cancer.

Citation Format: Gwark SC, Lee JW, Lee SB, Sohn G, Kim J, Chung IY, Kim HJ, Ko BS, Son BH, Ahn SH. Clinicopathologic characteristics and prognostic factors of pure mucinous breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-07-29.

The relationship between fatty liver index and bone mineral density in Koreans: KNHANES 2010-2011

Analyses using a nationally representative cohort have revealed that high fatty liver index (FLI) is associated with low bone mineral density (BMD) regardless of insulin resistance in men, thereby supporting the deteriorated bone metabolism in nonalcoholic fatty liver disease (NAFLD).

INTRODUCTION

NAFLD is linked to deteriorated bone health. We investigated the association of FLI, a scoring model for NAFLD, with BMD.

METHODS

This was a population-based, cross-sectional study from the Korea National Health and Nutrition Examination Surveys including 4264 Koreans (1908 men and 2356 women). FLI was calculated using body mass index, waist circumference, serum triglyceride, and gamma-glutamyltranspeptidase level. Insulin resistance was evaluated using the homeostasis model assessment-estimated insulin resistance (HOMA-IR) index. BMD was measured using dual-energy X-ray absorptiometry at the lumbar spine, total hip, femoral neck, and whole body.

RESULTS

Men had a higher FLI than women, while the HOMA-IR index was similar between men and women. The significant association between FLI and BMD was observed only in men, but not in women. FLI was negatively correlated with total hip, femoral neck, and whole body BMD in men after adjusting for all potential confounders, including HOMA-IR (P < 0.001 to 0.010). Lumbar spine, total hip, femoral neck, and whole body BMD in men showed a decreasing trend as the FLI tertile increased after adjusting for all potential confounders, including HOMA-IR (P for trends < 0.001 to 0.034). In men aged 50 years or older, odds ratios for combined osteopenia and osteoporosis increased across increasing FLI tertiles after adjusting for confounders (P for trends < 0.011 to 0.029).

CONCLUSION

NAFLD is associated with low bone density regardless of insulin resistance in men. These findings suggest an undiscovered direct link between liver and bone that increases the risk of osteoporosis in men with NAFLD.

Comparison of shoulder strength in males with and without myofascial trigger points in the upper trapezius

BACKGROUND

This study was conducted in order to compare the strength of scapular elevator and shoulder abductor with and without restricted scapular elevation between male subjects with and without myofascial trigger points in the upper trapezius.

METHODS

In total, 15 male subjects with myofascial trigger points, and 15age- and weight-matched male subjects without myofascial trigger points in the upper trapezius. Each subject was measured in the strength of maximum isometric scapular elevation and shoulder abduction with and without restricted scapular elevation. Maximum isometric contractions were measured using the Smart KEMA strength measurement system. Independent t-tests were used to compare shoulder strength values between the myofascial trigger points and non- myofascial trigger points groups.

FINDING

The results showed that shoulder abductor strength in the group with myofascial trigger points (5.64kgf) was significantly lower than in the group without myofascial trigger points (11.96kgf) when scapular elevation was restricted (p<0.05). However, there was no significant difference in the strength of the scapular elevator or shoulder abductor between groups (p>0.05).

INTERPRETATION

These findings suggest that decreased strength in the shoulder abductor with restricted scapular elevation should be considered in evaluating and treating individuals with myofascial trigger points of the upper trapezius.

groEL is a suitable genetic marker for detecting Vibrio parahaemolyticus by loop-mediated isothermal amplification assay

A groEL gene-based loop-mediated isothermal amplification (LAMP) assay was developed to detect Vibrio parahaemolyticus in contaminated seafood and water. The assay was optimized and conducted at 63°C for 40 min using Bacillus stearothermophilus (Bst) DNA polymerase, large fragment. Amplification was analysed via multiple detection methods, including opacity, formation of white precipitate, DNA intercalating dyes (ethidium bromide and SYBR Green I), metal ion-binding indicator dye, calcein, and 2% agarose gel electrophoresis. A characteristic ladder-like band pattern on agarose gel and the desired colour changes when using different dyes were observed in positive cases, and these were species-specific for V. parahaemolyticus when compared with other closely related Vibrio spp. The limit of detection (LoD) of this assay was 100 fg per reaction, 100-fold higher than that for conventional polymerase chain reaction (PCR). When tested on artificially contaminated seafood and seawater, the LoDs of the LAMP assay were 120 and 150 fg per reaction respectively, and those of conventional PCR were 120 and 150 pg per reaction respectively. Based on our results, the groEL gene-based LAMP assay is rapid, specific, sensitive, and reliable for detecting V. parahaemolyticus, and it could be used in field diagnosis.

SIGNIFICANCE AND IMPACT OF THE STUDY

The loop-mediated isothermal amplification (LAMP) assay using groEL gene (an abundant, highly conserved gene and member of the groESL chaperone gene family) provided rapid, species-specific and highly sensitive method for detecting Vibrio parahaemolyticus, the leading causal agent of seafood-borne diseases worldwide. Moreover, groEL LAMP revealed high efficiency than conventional PCR assay for V. parahaemolyticus using template both from pure culture and artificially contaminated seafood and water, which indicated the applicability in the field and environmental screening purpose for the organism.

Association of circulating dipeptidyl-peptidase 4 levels with osteoporotic fracture in postmenopausal women

Postmenopausal women with osteoporotic fracture (OF) had higher plasma dipeptidyl-peptidase 4 (DPP4) levels than those without. Furthermore, higher plasma DPP4 levels were significantly associated with higher bone turnover and a higher prevalence of OF. These results indicated that DPP4 may be associated with OF by mediating bone turnover rate.

INTRODUCTION

Evidence indicates that dipeptidyl-peptidase 4 (DPP4) plays a distinct role in bone metabolism. However, there has been no report on the association, if any, between circulating DPP4 levels and osteoporosis-related phenotypes, including osteoporotic fracture (OF). Therefore, we performed a case-control study to investigate these associations in postmenopausal women.

METHODS

This study was conducted in multiple centers in Korea. We enrolled 178 cases with OF and 178 age- and body mass index-matched controls. OF was assessed by an interviewer-assisted questionnaire and lateral thoracolumbar radiographs. Bone turnover markers (BTMs), bone mineral density (BMD), and plasma DPP4 levels were obtained in all subjects.

RESULTS

After adjustment for potential confounders, subjects with OF had significantly higher DPP4 levels than those without (P = 0.021). Higher DPP4 levels were significantly positively associated with higher levels of all BTMs, but not with BMD at all measured sites. The differences in DPP4 levels according to OF status disappeared after an additional adjustment for each BTM, but not after adjustment for any BMD values. BTMs explained approximately half of the relationship between DPP4 and OF. The risk of OF was 3.80-fold (95% confidence interval = 1.53-9.42) higher in subjects in the highest DPP4 quartile than in those in the lowest quartile after adjustment for potential confounders, including femoral neck BMD.

CONCLUSIONS

DPP4 may be associated with OF by at least partly mediating the bone turnover rate. Circulating DPP4 levels may be a potential biomarker that could increase the predictive power of current fracture risk assessment models.

Abstract P6-09-38: Interaction between body mass index and hormone receptor status as a prognostic factor in node-positive breast cancer

Purpose: The aim of this study was to investigate the interaction between BMI at breast cancer diagnosis and the various factors including hormone-receptor, menopausal and nodal status, and to find a specific subgroup where BMI has an effect on breast cancer prognosis.

Methods: We retrospectively analyzed the data of 8,763 non-metastatic invasive breast cancer patients from the Asan Medical Center's research database. Overall survival (OS) and breast cancer-specific survival (BCSS) among BMI groups were compared using the Kaplan-Meier method and Cox proportional hazard model with interaction term.

Results: Only in node-positive breast cancer, there was a significant interaction between obesity (BMI ≥ 30.0 kg/m2) at diagnosis and positive hormone receptor which showed worse overall survival (OS) and breast cancer specific survival (BCSS) than normal weight patients (adjusted hazard ratio [HR] = 1.65, 95% confidence interval [CI] = 1.01 to 2.69 and HR = 1.90, 95% CI = 1.15 to 3.15, respectively). Underweight (BMI&lt;18.50 kg/m2) which interacted with negative hormone receptor status in node-positive breast cancer was associated with decreased OS (HR = 2.01, 95% CI = 1.02 to 3.98) and BCSS (HR = 2.15, 95% CI = 1.08 to 4.26). There was no significant interaction between BMI and hormone receptor status in node-negative setting and BMI did not interact with menopausal status in any population.

Conclusions: BMI interacts with hormone receptor status in node positive setting, thereby playing a role in the breast cancer prognosis.

Citation Format: Chung IY, Lee JW, Lee JS, Park YR, Lee Y, Lee SB, Kim HJ, Ko BS, Son BH, Ahn SH. Interaction between body mass index and hormone receptor status as a prognostic factor in node-positive breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-38.

Tenofovir versus tenofovir plus entecavir for chronic hepatitis B with lamivudine resistance and entecavir resistance

We compared the viral suppressive efficacy of tenofovir disoproxil fumarate (TDF) mono-rescue therapy (TDF group) and TDF plus entecavir (ETV) combination-rescue therapy (TDF + ETV group) in chronic hepatitis B (CHB) patients with lamivudine resistance and entecavir resistance. One hundred and thirty-three CHB patients with lamivudine and entecavir resistance were investigated. Ninety-six patients were treated with TDF and 37 with TDF + ETV for at least 6 months. We compared the virologic response rate (HBV DNA level <20 IU/mL) between the two groups and identified the predictive factors of treatment outcome. There were no significant differences between the two groups in demographic characteristics. Up to 24 months [median: 18 (range 6-24) months], 85.4% and 89.2% of the TDF group and TDF + ETV group, respectively, achieved a virologic response (P=.068). Only the HBV DNA level at baseline was significantly associated with a virologic response in the multivariate analysis. In a subanalysis of patients with HBV DNA levels ≥4 log (IU/mL) at baseline, a higher proportion of patients in the TDF + ETV group than the TDF group achieved a virologic response (92.9% vs 68.3%; P<.001), while 90% of patients with HBV DNA (IU/mL) levels <4 log in all both TDF and TDF + ETV groups achieved a virologic response. TDF mono-rescue therapy is a reasonable option in patients with lamivudine resistance and entecavir resistance. However, the combination strategy should be considered in patients with high baseline HBV DNA levels.

Predictors of response to tenofovir disoproxil fumarate plus peginterferon alfa-2a combination therapy for chronic hepatitis B

BACKGROUND

In patients with chronic hepatitis B, tenofovir disoproxil fumarate (TDF) plus pegylated interferon (PEG-IFN) for 48-weeks results in higher rates of hepatitis B surface antigen (HBsAg) loss than either monotherapy.

AIM

To identify baseline and on-treatment factors associated with HBsAg loss at Week 72 and provide a model for predicting HBsAg loss in patients receiving combination therapy for 48 weeks.

METHODS

A secondary analysis of data from an open-label study where patients were randomised to TDF (300 mg/day, oral) plus PEG-IFN (PI, 180 μg/week, subcutaneous) for 48 weeks (TDF/PI-48w); TDF plus PEG-IFN for 16 weeks, TDF for 32 weeks (TDF/PI-16w+TDF-32w); TDF for 120 weeks (TDF-120w) or PEG-IFN for 48 weeks (PI-48w). Logistic regression methods were used to identify models that best predicted HBsAg loss at Week 72.

RESULTS

Rates of HBsAg loss at Week 72 were significantly higher in the TDF/PI-48w group (6.5%) than in the TDF/PI-16w+TDF-32w (0.5%), TDF-120w (0%) and PI-48w (2.2%) groups (P = 0.09). The only baseline factor associated with response was genotype A. HBsAg decline at Week 12 or 24 of treatment was associated with HBsAg loss at Week 72 (P < 0.001). HBsAg decline >3.5 log₁₀ IU/mL at Week 24 in the TDF/PI-48w group resulted in a positive predictive value of 85% and a negative predictive value of 99% for HBsAg loss at Week 72.

CONCLUSIONS

HBsAg decline at Week 24 of TDF plus PEG-IFN combination therapy may identify patients who, after completing 48 weeks of treatment, have a better chance of achieving HBsAg loss at Week 72.