Germline and Somatic Fumarate Hydratase Testing in Atypical Uterine Leiomyomata

Women with germline pathogenic variants (PV) in the fumarate hydratase (FH) gene develop cutaneous and uterine leiomyomata and have an increased risk of developing aggressive renal cell carcinomas. Many of these women are unaware of their cancer predisposition until an atypical uterine leiomyoma is diagnosed during a myomectomy or hysterectomy, making a streamlined genetic counseling process after a pathology-based atypical uterine leiomyoma diagnosis critical. However, the prevalence of germline pathogenic/likely PVs in FH among atypical uterine leiomyomata cases is unknown. To better understand FH germline PV prevalence and current patterns of genetic counseling and germline genetic testing, we undertook a retrospective review of atypical uterine leiomyomata cases at a single large center. We compared clinical characteristics between the FH PV, FH wild-type (WT), and unknown genetic testing cohorts. Of the 144 cases with atypical uterine leiomyomata with evaluable clinical data, only 49 (34%) had documented genetic test results, and 12 (8.3%) had a germline FH PV. There were 48 IHC-defined FH-deficient cases, of which 41 (85%) had FH testing and nine had a germline FH PV, representing 22% of the tested cohort and 18.8% of the FH-deficient cohort. Germline FH PVs were present in 8.3% of evaluable patients, representing 24.5% of the cohort that completed genetic testing. These data highlight the disconnect between pathology and genetic counseling, and help to refine risk estimates that can be used when counseling patients with atypical uterine leiomyomata.

PREVENTION RELEVANCE

Women diagnosed with fumarate hydratase (FH)-deficient uterine leiomyomata are at increased risk of renal cancer. This work suggests a more standardized pathology-genetic counseling referral pathway for these patients, and that research on underlying causes of FH-deficient uterine leiomyomata in the absence of germline FH pathogenic/likely pathogenic variants is needed.

Targeting Galectin 3 illuminates its contributions to the pathology of uterine serous carcinoma

BACKGROUND

Uterine serous cancer (USC) comprises around 10% of all uterine cancers. However, USC accounts for approximately 40% of uterine cancer deaths, which is attributed to tumor aggressiveness and limited effective treatment. Galectin 3 (Gal3) has been implicated in promoting aggressive features in some malignancies. However, Gal3's role in promoting USC pathology is lacking.

METHODS

We explored the relationship between LGALS3 levels and prognosis in USC patients using TCGA database, and examined the association between Gal3 levels in primary USC tumors and clinical-pathological features. CRISPR/Cas9-mediated Gal3-knockout (KO) and GB1107, inhibitor of Gal3, were employed to evaluate Gal3's impact on cell function.

RESULTS

TCGA analysis revealed a worse prognosis for USC patients with high LGALS3. Patients with no-to-low Gal3 expression in primary tumors exhibited reduced clinical-pathological tumor progression. Gal3-KO and GB1107 reduced cell proliferation, stemness, adhesion, migration, and or invasion properties of USC lines. Furthermore, Gal3-positive conditioned media (CM) stimulated vascular tubal formation and branching and transition of fibroblast to cancer-associated fibroblast compared to Gal3-negative CM. Xenograft models emphasized the significance of Gal3 loss with fewer and smaller tumors compared to controls. Moreover, GB1107 impeded the growth of USC patient-derived organoids.

CONCLUSION

These findings suggest inhibiting Gal3 may benefit USC patients.

Sialyl-Tn serves as a potential therapeutic target for ovarian cancer

BACKGROUND

Ovarian cancer remains the deadliest of the gynecologic cancers in the United States. There have been limited advances in treatment strategies that have seen marked increases in overall survival. Thus, it is essential to continue developing and validating new treatment strategies and markers to identify patients who would benefit from the new strategy. In this report, we sought to further validate applications for a novel humanized anti-Sialyl Tn antibody-drug conjugate (anti-STn-ADC) in ovarian cancer.

METHODS

We aimed to further test a humanized anti-STn-ADC in sialyl-Tn (STn) positive and negative ovarian cancer cell line, patient-derived organoid (PDO), and patient-derived xenograft (PDX) models. Furthermore, we sought to determine whether serum STn levels would reflect STn positivity in the tumor samples enabling us to identify patients that an anti-STn-ADC strategy would best serve. We developed a custom ELISA with high specificity and sensitivity, that was used to assess whether circulating STn levels would correlate with stage, progression-free survival, overall survival, and its value in augmenting CA-125 as a diagnostic. Lastly, we assessed whether the serum levels reflected what was observed via immunohistochemical analysis in a subset of tumor samples.

RESULTS

Our in vitro experiments further define the specificity of the anti-STn-ADC. The ovarian cancer PDO, and PDX models provide additional support for an anti-STn-ADC-based strategy for targeting ovarian cancer. The custom serum ELISA was informative in potential triaging of patients with elevated levels of STn. However, it was not sensitive enough to add value to existing CA-125 levels for a diagnostic. While the ELISA identified non-serous ovarian tumors with low CA-125 levels, the sample numbers were too small to provide any confidence the STn ELISA would meaningfully add to CA-125 for diagnosis.

CONCLUSIONS

Our preclinical data support the concept that an anti-STn-ADC may be a viable option for treating patients with elevated STn levels. Moreover, our STn-based ELISA could complement IHC in identifying patients with whom an anti-STn-based strategy might be more effective.

Dung removal increases under higher dung beetle functional diversity regardless of grazing intensification

Dung removal by macrofauna such as dung beetles is an important process for nutrient cycling in pasturelands. Intensification of farming practices generally reduces species and functional diversity of terrestrial invertebrates, which may negatively affect ecosystem services. Here, we investigate the effects of cattle-grazing intensification on dung removal by dung beetles in field experiments replicated in 38 pastures around the world. Within each study site, we measured dung removal in pastures managed with low- and high-intensity regimes to assess between-regime differences in dung beetle diversity and dung removal, whilst also considering climate and regional variations. The impacts of intensification were heterogeneous, either diminishing or increasing dung beetle species richness, functional diversity, and dung removal rates. The effects of beetle diversity on dung removal were more variable across sites than within sites. Dung removal increased with species richness across sites, while functional diversity consistently enhanced dung removal within sites, independently of cattle grazing intensity or climate. Our findings indicate that, despite intensified cattle stocking rates, ecosystem services related to decomposition and nutrient cycling can be maintained when a functionally diverse dung beetle community inhabits the human-modified landscape.

Endometrial Cancer Risk Among Germline BRCA1/2 Pathogenic Variant Carriers: Review of Our Current Understanding and Next Steps

PURPOSE

To review the literature exploring endometrial cancer (EC) risk among surgical candidates with germline BRCA1/2 pathogenic variants (PVs) to guide decisions around risk-reducing (rr) hysterectomy in this population.

DESIGN

A comprehensive review was conducted of the current literature that influences clinical practice and informs expert consensus. We present our understanding of EC risk among BRCA1/2 PV carriers, the risk-modifying factors specific to this patient population, and the available research technology that may guide clinical practice in the future. Limitations of the existing literature are outlined.

RESULTS

Patients with BRCA1/2 PVs, those with a personal history of tamoxifen use, those who desire long-term hormone replacement therapy, and/or have an elevated BMI are at higher risk of EC, primarily endometrioid EC and/or uterine papillary serous carcinoma, and may benefit from rr-hysterectomy. Although prescriptive clinical guidelines specific to BRCA1/2 PV carriers could inform decisions around rr-hysterectomy, limitations of the current literature prevent more definitive guidance at this time. A large population-based study of a contemporary cohort of BRCA1/2 PV carriers with lifetime follow-up compared with cancer-gene negative controls would advance this topic and facilitate care decisions.

CONCLUSION

This review validates a potential role for rr-hysterectomy to address EC risk among surgical candidates with BRCA1/2 PVs. Evidence-based clinical guidelines for rr-hysterectomy in BRCA1/2 PV carriers are essential to ensure equitable access to this preventive measure, supporting insurance coverage for patients with either BRCA1 or BRCA2 PVs to pursue rr-hysterectomy. Overall, this review highlights the complexity of EC risk in BRCA1/2 PV carriers and offers a comprehensive framework to shared decision making to inform rr-hysterectomy for BRCA1/2 PV carriers.

Abstract 4309: Early apoptotic measurements of patient-derived organoids predict patient response to therapy

The use of imperfect models and ex vivo culture systems to try to predict patient drug response represents an enormous bottle neck in cancer treatment. Nonetheless, determining how effective an approved drug will be for an individual cancer patient, as well as identifying novel compounds that may be beneficial to a specific population often requires the use of primary tumor cells. Patient-derived organoids represent an intermediate between primary tumor cells, whose limited supply may hinder reliable drug testing, and cell lines, which often do not reflect what happens in vivo. Herein, we describe the development of a novel assay platform, termed 3D-DBP (3D dynamic BH3 profiling), to detect early apoptotic measurements in ovarian cancer patient-derived organoids and present evidence that this method can be used to predict patient response to therapy. We have optimized the use of patient-derived organoids from 16 individual tumors in a microscopy-based imaging assay. We image the BH3 peptide-induced release of cytochrome c from mitochondria, which indicates permeabilization of the outer mitochondrial membrane, in intact organoids. The less cytochrome c retained in each organoid, the more primed that organoid is for apoptosis. By comparing results of drug-treated and untreated cells, we can identify drugs that cause a significant increase in apoptotic priming in organoids. In the 16 patient-derived organoids investigated this 3D DBP technique was an effective means of predicting patient response to carboplatin therapy. In summary, we have not only created a means of visualizing drug response in intact organoids, but also have demonstrated its clinical utility.

Citation Format: Kelley E. McQueeney, Patrick Bhola, Sarah J. Hill, Anthony Letai. Early apoptotic measurements of patient-derived organoids predict patient response to therapy. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4309.

Effects of axitinib and lenvatinib on cardiovascular function and haemodynamic

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): EU Horizon 2020 Research and Innovation programme, under the Marie Skłodowska-Curie European Training Network

Background

The introduction of novel anticancer treatments, targeting vascular endothelial growth factor receptors (VEGFRs), has changed the therapeutic approach in oncology. However, with their introduction in clinical practice, unanticipated cardiovascular complications emerged, including hypertension, left ventricular dysfunction and thromboembolism [1]. Even though these therapeutics strongly affect haemodynamic balance in patients, the pathophysiological mechanisms by which they impair cardiovascular function are still largely unknown, leading to a reduction of therapeutic dosage or to a temporary or permanent treatment interruption [2].

Purpose

The severity of cardiovascular complications following the treatment with VEGFR inhibitors, along with the lack of antihypertensive strategies able to adequately manage these events, require an unequivocal and urgent assessment of their cardiovascular safety. This study aims to determine the extent to which VEGFR inhibitors impact on cardiovascular function, profiling their effect on regional haemodynamic responses. Their cardiovascular assessment represents a valuable opportunity to investigate the mechanisms underlying cardiovascular toxicities induced by these novel antiangiogenic treatments.

Methods

This study evaluated the haemodynamic effects of selected receptor tyrosine kinase inhibitors (RTKIs), namely axitinib and lenvatinib, in conscious and freely moving rats using the Doppler Flowmetry technique. Male Sprague Dawley Rats (350-450 g) were chronically implanted with pulsed Doppler flow probes (around the renal and mesenteric arteries, and the descending abdominal aorta) and catheters (jugular vein and distal abdominal aorta) [3]. Haemodynamic parameters were measured over 4 days, before and after daily administration of axitinib (3 and 6 mg/kg, 3 and 6 mg/kg/h for 1 h, i.v.), or lenvatinib (3 and 6 mg/kg, 3 and 6 mg/kg/h for 1 h, i.v.).

Results

Both axitinib and lenvatinib evoked a significant hypertensive response, which progressively increased over the 4 days. This pressor effect was associated with a notable decrease of vascular conductance in the hindquarters. Lenvatinib caused a more marked vasoconstriction in mesenteric and renal vessels when compared to axitinib, which only elicited a renal vasoconstrictive effect at the highest dose used.

Conclusions

This study showed that the axitinib- and lenvatinib-induced hypertensive response is associated with regionally selective vasoconstrictions, which consistently occur in the hindquarters vascular bed. However, their vasoconstrictive profile differs in the renal and mesenteric vasculature. In addition, the Doppler Flowmetry model showed to be a translational approach to predict the detrimental cardiovascular effects of these anticancer drugs, since the increase in blood pressure observed with this method reflects the hypertensive response reported in clinical practice.

Global urban environmental change drives adaptation in white clover

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale.

Acute PR3-ANCA vasculitis in an asymptomatic COVID-19 teenager

We present the case of an acute onset ANCA positive vasculitis in an asymptomatic COVID-19 infected teenager, resulting in significant colonic damage. The patient was initially diagnosed with Henoch-Schönlein purpura and presented with worsening symptoms with significant necrosis of her perineum and rectum requiring surgical debridement and diverting colostomy. As a part of her work-up, she tested positive for COVID-19 total IgG/IgM antibodies and ANCA antibodies. This case complements previously reported cases of COVID-19 induced autoimmune disease in children but is novel in describing extensive intestinal disease as a result of an autoimmune vasculitis in a child.

Assessment of Combined Nivolumab and Bevacizumab in Relapsed Ovarian Cancer: A Phase 2 Clinical Trial

Importance

To date, single-agent programmed cell death 1 protein 1 (PD-1)/programmed death ligand 1 (PD-L1) immune checkpoint blockade has shown limited activity in recurrent epithelial ovarian cancer. Combination strategies of PD-1/PD-L1 inhibition with antiangiogenic therapy have the potential for synergistic activity through modulation of the microenvironment and represent a potential therapeutic opportunity in this disease.

Objective

To evaluate the activity of combined nivolumab and bevacizumab in women with relapsed ovarian cancer.

Design, Setting, and Participants

A single-arm, phase 2 study enrolled patients between February 8, 2017, and December 29, 2017, at 2 sites in the United States; the primary data analysis was completed July 27, 2018. Thirty-eight women with relapsed epithelial ovarian cancer were enrolled in this study. Participants had disease recurrence within 12 months of their last platinum-based therapy and had received between 1 and 3 lines of prior therapy.

Interventions

Participants received intravenous nivolumab and intravenous bevacizumab once every 2 weeks.

Main Outcome and Measures

The primary end point was objective response rate (ORR) as measured by Response Evaluation Criteria in Solid Tumors 1.1. Secondary end points included evaluation of the ORR by platinum sensitivity, assessment of progression-free survival, assessment of safety data, and investigation of the association of tumor PD-L1 with response to therapy.

Results

Of the 38 women enrolled, 18 had platinum-resistant and 20 had platinum-sensitive disease; mean (SD) age was 63.0 (9.1) years. Eleven patients experienced a confirmed response to nivolumab with bevacizumab (ORR, 28.9%; 95% exact binomial CI, 15.4%-45.9%), with 1 additional unconfirmed response. The ORR was 40.0% (19.1%-64.0%) in platinum-sensitive and 16.7% (95% CI 3.6%-41.4%) in platinum-resistant participants. Thirty-four participants (89.5%) experienced at least 1 treatment-related adverse event; 9 participants (23.7%) experienced a grade 3 or higher treatment-related adverse event. Median progression-free survival was 8.1 months (95% CI, 6.3-14.7 months). In 36 histologic samples for which PD-L1 testing could be performed, 22 samples (61.1%) had a PD-L1 tumoral percentage less than 1, and 14 samples (38.9%) had a PD-L1 tumoral percentage of 1 or greater. Ten responses occurred in patients with PD-L1 tumor percentage less than 1, and 2 in patients with PD-L1 tumor percentages of 1 or greater.

Conclusions and Relevance

The nivolumab with bevacizumab combination appeared to show activity in patients with relapsed ovarian cancer, with greater activity in the platinum-sensitive setting. Alternative combinational strategies may be necessary in the platinum-resistant setting.

Enhanced Efficacy of Aurora Kinase Inhibitors in G2/M Checkpoint Deficient TP53 Mutant Uterine Carcinomas Is Linked to the Summation of LKB1-AKT-p53 Interactions

Simple Summary

Cancers arising from the lining of the uterus, endometrial cancers, are the most common gynecologic malignancy in the United States. Once endometrial cancer escapes the uterus and grows in distant locations, there are limited therapeutic options. The most aggressive and lethal endometrial cancers carry alterations in the protein p53, which is a critical guardian of many cellular functions. The role of these p53 alterations in endometrial cancer is not well understood. The goal of this work was to use p53 altered models of endometrial cancer to understand which, if any, therapeutically targetable vulnerabilities these p53 alterations may confer in endometrial cancer. Here we show that many of these p53 altered cells have problems with cell division which can be targeted with novel single and combination therapies. These discoveries may lead to relevant new therapies for difficult to treat advanced stage endometrial cancers.

Abstract

Uterine carcinoma (UC) is the most common gynecologic malignancy in the United States. TP53 mutant UCs cause a disproportionate number of deaths due to limited therapies for these tumors and the lack of mechanistic understanding of their fundamental vulnerabilities. Here we sought to understand the functional and therapeutic relevance of TP53 mutations in UC. We functionally profiled targetable TP53 dependent DNA damage repair and cell cycle control pathways in a panel of TP53 mutant UC cell lines and patient-derived organoids. There were no consistent defects in DNA damage repair pathways. Rather, most models demonstrated dependence on defective G2/M cell cycle checkpoints and subsequent upregulation of Aurora kinase-LKB1-p53-AKT signaling in the setting of baseline mitotic defects. This combination makes them sensitive to Aurora kinase inhibition. Resistant lines demonstrated an intact G2/M checkpoint, and combining Aurora kinase and WEE1 inhibitors, which then push these cells through mitosis with Aurora kinase inhibitor-induced spindle defects, led to apoptosis in these cases. Overall, this work presents Aurora kinase inhibitors alone or in combination with WEE1 inhibitors as relevant mechanism driven therapies for TP53 mutant UCs. Context specific functional assessment of the G2/M checkpoint may serve as a biomarker in identifying Aurora kinase inhibitor sensitive tumors.

Chemical syntheses of the salvinorin chemotype of KOR agonist

Covering: 2000 to 2020 The hallucinogenic diterpene salvinorin A potently and selectively agonizes the human kappa-opioid receptor (KOR). Its unique attributes-lack of a basic nitrogen, rapid brain penetrance, short half-life-combined with the potential of KOR as an emerging target for analgesics have stimulated extensive medicinal chemistry based on semi-synthesis from extracts of Salvia divinorum. Total synthesis efforts have delivered multiple, orthogonal routes to salvinorin A, its congeners and related analogs with the goal of optimizing its activity towards multiple functional endpoints. Here we review total syntheses of the salvinorin chemotype and discuss outstanding problems that synthesis can address in the future.

Enhanced Efficacy of Simultaneous PD-1 and PD-L1 Immune Checkpoint Blockade in High-Grade Serous Ovarian Cancer

Immune therapies have had limited efficacy in high-grade serous ovarian cancer (HGSC), as the cellular targets and mechanism(s) of action of these agents in HGSC are unknown. Here we performed immune functional and single-cell RNA sequencing transcriptional profiling on novel HGSC organoid/immune cell co-cultures treated with a unique bispecific anti-programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) antibody compared with monospecific anti-PD-1 or anti-PD-L1 controls. Comparing the functions of these agents across all immune cell types in real time identified key immune checkpoint blockade (ICB) targets that have eluded currently available monospecific therapies. The bispecific antibody induced superior cellular state changes in both T and natural killer (NK) cells. It uniquely induced NK cells to transition from inert to more active and cytotoxic phenotypes, implicating NK cells as a key missing component of the current ICB-induced immune response in HGSC. It also induced a subset of CD8 T cells to transition from naïve to more active and cytotoxic progenitor-exhausted phenotypes post-treatment, revealing the small, previously uncharacterized population of CD8 T cells responding to ICB in HGSC. These state changes were driven partially through bispecific antibody-induced downregulation of the bromodomain-containing protein BRD1. Small-molecule inhibition of BRD1 induced similar state changes in vitro and demonstrated efficacy in vivo, validating the co-culture results. Our results demonstrate that state changes in both NK and a subset of T cells may be critical in inducing an effective anti-tumor immune response and suggest that immune therapies able to induce such cellular state changes, such as BRD1 inhibitors, may have increased efficacy in HGSC. SIGNIFICANCE: This study indicates that increased efficacy of immune therapies in ovarian cancer is driven by state changes of NK and small subsets of CD8 T cells into active and cytotoxic states.

Abstract PR06: Dissecting mechanisms of replication fork stabilization in patient-derived high-grade serous organoid cultures and their impact on therapeutic sensitivity and the immune-tumor interaction

Genomic analyses indicate that 50% of high-grade serous ovarian cancers (HGSC) harbor a genomic alteration in a DNA damage repair gene that may lead to functional defects. Using functional assays on patient-derived HGSC organoid cultures to test the capacity of the tumor cells to repair double-strand DNA breaks and to protect stalled replication forks, we have found that many HGSCs have stalled fork protection defects regardless of the genomic background of the tumor and that these defects correlate with sensitivity to replication stress inducing therapeutic agents. We hypothesized that gaining a better understanding of the mechanisms of replication fork instability and stability in HGSC organoid cultures would help to better understand the mechanisms of therapeutic sensitivity of the tumor cells. The purpose of this work is to understand how replication fork stabilization either in the primary tumor or through selection post-treatment leads to alterations in tumor cell biology, including therapeutic sensitivity and interaction of the tumor cells with the surrounding microenvironment. We utilized bulk RNA sequencing analysis of HGSC organoid cultures with varied replication fork protection capacity, some matched pairs of untreated and post-neoadjuvant tumors, to stratify differences in functional profiles in fork stable versus unstable tumors; we then used basic molecular biology techniques to understand the mechanisms of fork stabilization and how this stabilization affects the therapeutic sensitivity of the cells. We also developed and utilized multiple functional assays to assess the interaction of HGSC organoids of varying fork protection capacity with their immune microenvironment in different drug exposure settings. We identified multiple proteins that through either up- or downregulation lead to stabilization of replication forks in the tumor cells and found that the mechanisms of stabilization can occur at both the level of the replication fork and the overall transcriptional level of the cell and can alter the therapeutic sensitivity of the cells. We have determined that replication fork stability leads to increased mesenchymal characteristics in tumors and to decreased activation of the antitumor immune response within the cultures after treatment with DNA damage repair and immuno-oncologic (IO) agents. Overall, these results indicate that replication fork stabilization in HGSC through multiple different mechanisms can lead to altered interactions of the tumor cells with their microenvironment and altered therapeutic sensitivity.

This abstract is also being presented as Poster B10.

Citation Format: Sarah J. Hill, Patrick Lizotte, Nikolas Kesten, Neil S. Horowitz, Michael G. Muto, Michael J. Worley, Colleen M. Feltmate, Ross S. Berkowitz, Henry Long, Ursula A. Matulonis, Christopher P. Crum, Myles Brown, Alan D. D'Andrea. Dissecting mechanisms of replication fork stabilization in patient-derived high-grade serous organoid cultures and their impact on therapeutic sensitivity and the immune-tumor interaction [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr PR06.

Cystic Biliary Atresia: A Wolf in Sheep's Clothing

Neonatal obstructive jaundice is frequently explained by biliary atresia (BA) or the presence of a choledochal cyst (CC). Cystic biliary atresia (CBA) has been a proposed as a subtype of BA with projected improved outcomes. We aimed to characterize these lesions further. We conducted an Institutional Review Board-approved review of all patients treated for obstructive jaundice at our tertiary children's hospital over 10 years. Over the decade we evaluated 91 children with obstructive jaundice: 13 CBA, 52 BA, and 26 CC. Patients with isolated CBA and BA were diagnosed significantly earlier than those with CC (15.9, 54, and 281 days, respectively; P = 0.0001). There was a significant delay between diagnosis and surgical intervention for patients with CBA compared with BA: 17 days versus 5.7 days ( P = 0.004). There was no difference in rate of transplant between CBA and BA (31 vs 50%; P = 0.35). The time from surgery until transplant was 13.9 and 18.6 months for CBA and BA, respectively ( P = 0.62). Although radiographically similar to CC, CBA behaves similarly to isolated BA. Delay in recognition and surgical treatment may affect outcomes and lead to an increased incidence of liver failure. The presence of a cystic biliary malformation in the setting of neonatal jaundice should be regarded as CBA until proven otherwise.

Abstract AP10: REAL-TIME ASSESSMENT OF HGSC DNA DAMAGE REPAIR DEFECTS AND DEFECT-INDUCED RESPONSE TO THERAPY IN OVARIAN CANCER ORGANOIDS

Patients with High Grade Serous Ovarian Cancer (HGSC) have limited therapeutic options. Immuno-oncologic (IO) agents have had limited effect. DNA damage repair gene mutations that may confer repair defects have been identified in up to 50% of HGSCs, making therapies that target repair defects, like PARP, CHK1, and ATR inhibitors, additional options. We have no means of predicting which patients will respond to any of these therapies.

A model system that allows for functional assays to assess for DNA damage repair defects, prediction of response to therapies targeting such defects, and assessment of the functionality of the tumor immune infiltrate and its response to IO agents is needed. Organoids are three-dimensional structures derived from human normal or tumor tissue cells that anatomically and functionally mimic the developed human organ. Organoids mimicking the parent tumor from which they were derived have aided in the study of multiple tumor types. They are inexpensive and easily manipulated and may be an ideal model system for studying ovarian cancer.

We have devised a functional assay platform to profile the DNA damage repair capacity and immune targetability of short-term patient-derived HGSC organoids. The organoids mimic the tumors from which they were derived morphologically, molecularly, and genetically.

We have tested 33 organoid cultures derived from 21 HGSC patients for homologous recombination (HR) and replication fork protection capacity and compared the functional results to the tumor genomic profile. Regardless of repair gene mutational status, an HR functional defect in the organoids correlated with PARP inhibitor sensitivity. A fork protection functional defect correlated with carboplatin, and ATR and CHK1 inhibitor sensitivity. Importantly, this work has led to the discovery of potential therapeutic combinations, such as a CHK1 inhibitor plus carboplatin or gemcitabine that may be useful in treating tumors otherwise resistant to most therapies. Drugs such as carboplatin or gemcitabine can synergize with a CHK1 inhibitor by enhancing replication stress and fork deprotection.

In parallel, we have immune phenotyped the parent tumors and organoid cultures from 15 patients, and shown that the organoid cultures retain lymphocytes expressing relevant IO receptors in the short term. Upon treatment with carboplatin, olaparib, and pembrolizumab as single agents or in combination, we detect changes in IO receptor expression and production of different cytokines in the cultures, suggesting an immune response induced by these agents. We have detected receptor and cytokine alterations that would create an immune suppressive environment with specific drug combinations in tumors with specific repair defects, suggesting that these may be inappropriate combinations for harnessing the immune system in tumors with specific repair capacities.

Continued combined immune and DNA damage repair phenotyping analyses of the organoids will lead to a better understanding of which mechanistic defects are needed to confer sensitivity to DNA damage repair agents, what functional properties and immune milieu lead to sensitivity to IO agents, and how best to combine such therapies. In addition, through further correlation with patient responses over time, HGSC organoids may become a useful tool for rapidly predicting patient response to therapeutic agents.

Citation Format: Sarah J. Hill, Brennan Decker, Emma A. Roberts, Chunyu Yang, Neil S. Horowitz, Michael G. Muto, Michael J. Worley Jr., Colleen M. Feltmate, Marisa R. Nucci, Elizabeth M. Swisher, Ryuji Morizane, Bose Kochupurakkal, Khanh T. Do, Panagiotis Konstantinopoulos, Joyce F. Liu, Joseph V. Bonventre, Ursula A. Matulonis, Geoffrey I. Shapiro, Ross S. Berkowitz, Christopher P. Crum, and Alan D. D'Andrea. REAL-TIME ASSESSMENT OF HGSC DNA DAMAGE REPAIR DEFECTS AND DEFECT-INDUCED RESPONSE TO THERAPY IN OVARIAN CANCER ORGANOIDS [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr AP10.

The effect of EMAT coil geometry on the Rayleigh wave frequency behaviour

Understanding of optimal signal generation and frequency content for electromagnetic acoustic transducers (EMATs) is key to improving their design and signal to noise ratio. Linear and meander coil designs are fairly well understood, but other designs such as racetrack or focused coils have recently been proposed. Multiple transmission racetrack coil EMATs, with focused and unfocused designs, were constructed. The optimum driving frequency for maximum detected signal was found to range between 1.1 and 1.4 MHz on aluminium for a 1.5 mm width coil. A simple analytical model based on the instantaneous velocity of a wave predicts a maximum signal at 1.44 MHz. Modelling the detection coil as a spatial square wave agrees with this, and predicts a general relation of f_P=0.761v/L between the optimum frequency f_P, the wave velocity v, and the coil width L. A time domain model of the detection coil predicts a 1.4-1.5 MHz peak for continuous wave excitation, with a frequency that decreases as the length of the wavepacket is decreased, consistent with the experimental data. Linear coil modelling using the same technique is shown to be consistent with previous work, with improving detection at lower wave frequencies, and signal minima at every integer multiple of the wavelength. Finite Element Analysis (FEA) is used to model the effects of the spatial width of the racetrack generation coil and focused geometry, and no significant difference is found between the focused and the unfocused EMAT response. This highlights the importance of designing the EMAT coil for the correct lift-off and desired frequency of operation.

Predictive Potential of Head and Neck Squamous Cell Carcinoma Organoids

In this issue of Cancer Discovery, Driehuis and colleagues establish culture conditions for the rapid, efficient, and long-term expansion of healthy human oral mucosa and head and neck squamous cell carcinoma (HNSCC) tumor organoids. The HNSCC tumor organoids provide a functional platform for analyzing tumor cell phenotype, tumorigenic potential, and drug and radiotherapy response, and they have a potential role in clinical decision-making.See related article by Driehuis et al., p. 852.

Abstract 368A: Functional assessment of DNA damage repair defects and the anti-tumor immune response in high grade serous ovarian cancers using patient-derived organoids

Patients with high grade serous ovarian cancer (HGSC) have limited additional therapeutic options beyond traditional carboplatin and paclitaxel. Immuno-oncologic (IO) agents have had limited effect, and despite the fact that 50% of HGSCs have genomic alterations in DNA damage repair genes, we still have no means of predicting which of these tumors actually harbor repair defects and will respond to these agents. Using patient-derived organoids which contain patient immune cells, we have developed functional assays to test the DNA damage repair capacity, anti-tumor immune response, and therapeutic vulnerability of HGSCs. These assays include testing for defects in the two key DNA damage repair pathways, homologous recombination (HR) and stalled replication fork protection, testing for activity and specificity of the immune cells in the cultures against the tumor cells when exacerbated by specific therapeutic combinations, and testing for therapeutic sensitivity to targeted and traditional chemotherapy agents and IO agents either alone or in rational combinations. In parallel, many of the tumors and organoids have undergone genomic and RNA sequencing, searching for relevant alterations to explain detected defects. Flow cytometry analysis of the parent tumors and short term (7-10 day) organoids reveal that organoids contain an immune milieu with IO receptor expression levels similar to the parent tumors. Upon treatment with IO agents alone or in combination with chemotherapeutic agents, we have found that specific IO receptor expression is altered, certain combinations lead to induction of cytokine expression that may repress an anti-tumor response, and that some combinations do not induce the expected cytotoxicity. The DNA damage repair functional assays have revealed that in HGSC, stalled fork protection defects are more common than HR defects, regardless of the repair gene mutational status of the tumors. Importantly, there is a wider array of therapies available to target these defects. For instance, organoids with unstable replication forks are more sensitive to ATR and CHK1 inhibitors. Organoids with stable forks are more sensitive to combinations of drugs which confer replication stress, such as the combination of a CHK1 inhibitor plus gemcitabine. Overall, the repair assays will allow for a better understanding of the types and mechanisms of repair defects present in tumors and a more accurate prediction of sensitivity to targeted agents. The immune functional assays will allow for a better mechanistic understanding of what response specific agents actually induce in immune and tumor cells and allow for better rational therapeutic pairings. Through assessment of a larger number of patients, we hope to demonstrate that these functional assays can have a clinical impact in rapidly predicting patient response.

Citation Format: Sarah J. Hill, Patrick Lizotte, Neil S. Horowitz, Michael G. Muto, Michael J. Worley, Colleen M. Feltmate, Bose Kochupurakkal, Khanh T. Do, Panagiotis Konstantinopoulos, Marisa R. Nucci, Joyce F. Liu, Ursula A. Matulonis, Geoffrey I. Shapiro, Ross S. Berkowitz, Christopher P. Crum, Alan D. D'Andrea. Functional assessment of DNA damage repair defects and the anti-tumor immune response in high grade serous ovarian cancers using patient-derived organoids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 368A.

Prediction of DNA Repair Inhibitor Response in Short-Term Patient-Derived Ovarian Cancer Organoids

Based on genomic analysis, 50% of high-grade serous ovarian cancers (HGSC) are predicted to have DNA repair defects. Whether this substantial subset of HGSCs actually have functional repair defects remains unknown. Here, we devise a platform for functional profiling of DNA repair in short-term patient-derived HGSC organoids. We tested 33 organoid cultures derived from 22 patients with HGSC for defects in homologous recombination (HR) and replication fork protection. Regardless of DNA repair gene mutational status, a functional defect in HR in the organoids correlated with PARP inhibitor sensitivity. A functional defect in replication fork protection correlated with carboplatin and CHK1 and ATR inhibitor sensitivity. Our results indicate that a combination of genomic analysis and functional testing of organoids allows for the identification of targetable DNA damage repair defects. Larger numbers of patient-derived organoids must be analyzed to determine whether these assays can reproducibly predict patient response in the clinic.Significance: Patient-derived ovarian tumor organoids grow rapidly and match the tumors from which they are derived, both genetically and functionally. These organoids can be used for DNA repair profiling and therapeutic sensitivity testing and provide a rapid means of assessing targetable defects in the parent tumor, offering more suitable treatment options. Cancer Discov; 8(11); 1404-21. ©2018 AACR. This article is highlighted in the In This Issue feature, p. 1333.

Structure-based exploration and pharmacological evaluation of N-substituted piperidin-4-yl-methanamine CXCR4 chemokine receptor antagonists

Using the available structural information of the chemokine receptor CXCR4, we present hit finding and hit exploration studies that make use of virtual fragment screening, design, synthesis and structure-activity relationship (SAR) studies. Fragment 2 was identified as virtual screening hit and used as a starting point for the exploration of 31 N-substituted piperidin-4-yl-methanamine derivatives to investigate and improve the interactions with the CXCR4 binding site. Additionally, subtle structural ligand changes lead to distinct interactions with CXCR4 resulting in a full to partial displacement of CXCL12 binding and competitive and/or non-competitive antagonism. Three-dimensional quantitative structure-activity relationship (3D-QSAR) and binding model studies were used to identify important hydrophobic interactions that determine binding affinity and indicate key ligand-receptor interactions.

Thoracoscopic Repair of Congenital Diaphragmatic Hernia After Extracorporeal Membrane Oxygenation: Feasibility and Outcomes

INTRODUCTION

Thoracoscopic repair of congenital diaphragmatic hernia (CDH) has been associated with faster recovery, earlier extubation, and decreased morbidity. Nevertheless, thoracoscopic repair is rarely attempted in the post-extracorporeal membrane oxygenation (ECMO) patient. Commonly cited reasons for not attempting thoracoscopy include concerns that the patients' respiratory status is too tenuous to tolerate insufflation pressures or that presumed defect size is so large that it precludes thoracoscopic repair. Our purpose is to review our experience with post-ECMO thoracoscopic CDH repair and evaluate the success of this approach.

METHODS

We performed retrospective analysis of attempted thoracoscopic CDH repairs after ECMO decannulation at our institution from 2001 to 2015. Primary outcome was rate of conversion. Secondary outcomes were intraoperative end-tidal CO₂, time to extubation, and rate of recurrence.

RESULTS

We identified 21 post-ECMO patients in whom thoracoscopic CDH repair was attempted. Thoracoscopic repair was successfully completed in 28%. No patients had reported intolerance to insufflation at 3-7 mmHg. Average end-tidal CO₂ at 15 operative minutes was 36.9 mmHg in the thoracoscopic group versus 50.7 mmHg in the open group and at 60 minutes was 34.25 mmHg versus 45.6 mmHg, respectively. One patient in the thoracoscopic group died and 1 experienced a large pneumothorax. In the converted group there was one clinically significant pneumothorax and three pleural effusions. Survivors after thoracoscopy were extubated an average of 5.6 ± 2.6 days after surgery versus 19.4 ± 10 days in the converted group (P < .05). Recurrence rates at last follow-up were equal between the two groups at 20%.

CONCLUSIONS

Thoracoscopic CDH repair is both safe and feasible after ECMO with no increase in operative morbidity or mortality. Insufflation pressures of 3-7 mmHg are well tolerated without undue increase in end-tidal CO_2. When compared to conversion cases, thoracoscopic repair is associated with significantly decreased time to extubation with no difference in recurrence.

Higher predation risk for insect prey at low latitudes and elevations

Biotic interactions underlie ecosystem structure and function, but predicting interaction outcomes is difficult. We tested the hypothesis that biotic interaction strength increases toward the equator, using a global experiment with model caterpillars to measure predation risk. Across an 11,660-kilometer latitudinal gradient spanning six continents, we found increasing predation toward the equator, with a parallel pattern of increasing predation toward lower elevations. Patterns across both latitude and elevation were driven by arthropod predators, with no systematic trend in attack rates by birds or mammals. These matching gradients at global and regional scales suggest consistent drivers of biotic interaction strength, a finding that needs to be integrated into general theories of herbivory, community organization, and life-history evolution.

More inclusive bipolar mixed depression definition by permitting overlapping and non-overlapping mood elevation symptoms

OBJECTIVE

The objective of this study was to assess the strengths and limitations of a mixed bipolar depression definition made more inclusive than that of the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) by counting not only 'non-overlapping' mood elevation symptoms (NOMES) as in DSM-5, but also 'overlapping' mood elevation symptoms (OMES, psychomotor agitation, distractibility, and irritability).

METHODS

Among bipolar disorder (BD) out-patients assessed with the Systematic Treatment Enhancement Program for BD (STEP-BD) Affective Disorders Evaluation, we assessed prevalence, demographics, and clinical correlates of mixed vs. pure depression, using more inclusive (≥3 NOMES/OMES) and less inclusive DSM-5 (≥3 NOMES) definitions.

RESULTS

Among 153 depressed BD, counting not only NOMES but also OMES yielded a three-fold higher mixed depression rate (22.9% vs. 7.2%) and important statistically significant clinical correlates for mixed compared to pure depression (more lifetime anxiety disorder comorbidity, more current irritability, and less current antidepressant use), which were not significant using the DSM-5 threshold.

CONCLUSION

To conclude, further studies with larger numbers of patients with DSM-5 bipolar mixed depression assessing strengths and limitations of more inclusive mixed depression definitions are warranted, including efforts to ascertain whether or not OMES should count toward mixed depression.

More inclusive bipolar mixed depression definitions by requiring fewer non-overlapping mood elevation symptoms

OBJECTIVE

Assess strengths and limitations of mixed bipolar depression definitions made more inclusive than that of the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) by requiring fewer than three 'non-overlapping' mood elevation symptoms (NOMES).

METHOD

Among bipolar disorder (BD) out-patients assessed with Systematic Treatment Enhancement Program for BD (STEP-BD) Affective Disorders Evaluation, we assessed prevalence, demographics, and clinical correlates of mixed vs. pure depression, using less inclusive (≥3 NOMES, DSM-5), more inclusive (≥2 NOMES), and most inclusive (≥1 NOMES) definitions.

RESULTS

Among 153 depressed BD, compared to less inclusive DSM-5 threshold, our more and most inclusive thresholds, yielded approximately two- and five-fold higher mixed depression rates (7.2%, 15.0%, and 34.6% respectively), and important statistically significant clinical correlates for mixed compared to pure depression (e.g. more lifetime anxiety disorder comorbidity, more current irritability), which were not significant using the DSM-5 threshold.

CONCLUSION

Further studies assessing strengths and limitations of more inclusive mixed depression definitions are warranted, including assessing the extent to which enhanced statistical power vs. other factors contributes to more vs. less inclusive mixed bipolar depression thresholds having more statistically significant clinical correlates, and whether 'overlapping' mood elevation symptoms should be counted.

Presentation and management of pulmonary sequestration with total visceral inflow and outflow

Two of the most common types of congenital thoracic malformations are congenital pulmonary airway malformations (CPAMs) and bronchopulmonary sequestrations (BPS). Here we present the first known case of a hybrid lesion, with coexisting features of an extralobar sequestration (ELS) and CPAM type 2, with arterial inflow from the celiac trunk and venous outflow to the portal vein. The clinical presentation, investigative imaging and timing of surgery are discussed.

Detection of the secondary, low-affinity β1 -adrenoceptor site in living cells using the fluorescent CGP 12177 derivative BODIPY-TMR-CGP

Background and Purpose

CGP 12177 not only inhibits agonist effects mediated through the catecholamine site of the β₁-adrenoceptor with high affinity, but also exhibits agonist effects of its own at higher concentrations through a secondary, low-affinity β₁-adrenoceptor site or conformation. β-blocker affinities for this ‘CGP 12177’ site of the human β₁-adrenoceptor have thus far only been characterized in functional studies. Here, we used the fluorescent CGP 12177 analogue BODIPY-TMR-CGP to directly investigate receptor–ligand interactions at the secondary binding site of the β₁-adrenoceptor.

Experimental Approach

The human β₁-adrenoceptor was stably expressed in CHO cells containing a cAMP response element (CRE)-secreted placental alkaline phosphatase (SPAP) reporter gene construct. Functional responses of BODIPY-TMR-CGP were determined in the CRE-SPAP reporter gene assay, and manual and automated confocal microscopy platforms used to investigate the binding properties of BODIPY-TMR-CGP.

Key Results

BODIPY-TMR-CGP displayed a pharmacological profile similar to that of CGP 12177, retaining agonist activity at the secondary β₁-adrenoceptor site. In confocal microscopy studies, specific BODIPY-TMR-CGP binding allowed clear visualization of β₁-adrenoceptors in live cells. Using a wider concentration range of labelled ligand in a high-content fluorescence-based binding assay than is possible in radioligand binding assays, two-site inhibition binding curves of β-adrenoceptor antagonists were revealed in CHO cells expressing the human β₁-adrenoceptor, but not the β₂-adrenoceptor.

Conclusions and Implications

The fluorescent CGP 12177 analogue allowed the detection of the β₁-adrenoceptor secondary site in both functional and binding studies. This suggests that BODIPY-TMR-CGP presents an important and novel fluorescent tool to investigate the nature of the secondary β₁-adrenoceptor site.

BRCA1 recruitment to transcriptional pause sites is required for R-loop-driven DNA damage repair

The mechanisms contributing to transcription-associated genomic instability are both complex and incompletely understood. Although R-loops are normal transcriptional intermediates, they are also associated with genomic instability. Here, we show that BRCA1 is recruited to R-loops that form normally over a subset of transcription termination regions. There it mediates the recruitment of a specific, physiological binding partner, senataxin (SETX). Disruption of this complex led to R-loop-driven DNA damage at those loci as reflected by adjacent γ-H2AX accumulation and ssDNA breaks within the untranscribed strand of relevant R-loop structures. Genome-wide analysis revealed widespread BRCA1 binding enrichment at R-loop-rich termination regions (TRs) of actively transcribed genes. Strikingly, within some of these genes in BRCA1 null breast tumors, there are specific insertion/deletion mutations located close to R-loop-mediated BRCA1 binding sites within TRs. Thus, BRCA1/SETX complexes support a DNA repair mechanism that addresses R-loop-based DNA damage at transcriptional pause sites.

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Endogenous BRCA1 and senataxin (SETX) interact in a BRCA1-driven process

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BRCA1/SETX complexes are recruited to R-loop-associated termination regions (TRs)

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BRCA1/SETX complexes suppress transcriptional DNA damage arising at nearby R-loops

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BRCA1 breast cancers reveal indel mutations near BRCA1 TR binding regions

Systematic screening reveals a role for BRCA1 in the response to transcription-associated DNA damage

BRCA1 is a breast and ovarian tumor suppressor. Given its numerous incompletely understood functions and the possibility that more exist, we performed complementary systematic screens in search of new BRCA1 protein-interacting partners. New BRCA1 functions and/or a better understanding of existing ones were sought. Among the new interacting proteins identified, genetic interactions were detected between BRCA1 and four of the interactors: TONSL, SETX, TCEANC, and TCEA2. Genetic interactions were also detected between BRCA1 and certain interactors of TONSL, including both members of the FACT complex. From these results, a new BRCA1 function in the response to transcription-associated DNA damage was detected. Specifically, new roles for BRCA1 in the restart of transcription after UV damage and in preventing or repairing damage caused by stabilized R loops were identified. These roles are likely carried out together with some of the newly identified interactors. This new function may be important in BRCA1 tumor suppression, since the expression of several interactors, including some of the above-noted transcription proteins, is repeatedly aberrant in both breast and ovarian cancers.

BRCA1 pathway function in basal-like breast cancer cells

Sporadic basal-like cancers (BLCs) are a common subtype of breast cancer that share multiple biological properties with BRCA1-mutated breast tumors. Despite being BRCA1(+/+), sporadic BLCs are widely viewed as phenocopies of BRCA1-mutated breast cancers, because they are hypothesized to manifest a BRCA1 functional defect or breakdown of a pathway(s) in which BRCA1 plays a major role. The role of BRCA1 in the repair of double-strand DNA breaks by homologous recombination (HR) is its best understood function and the function most often implicated in BRCA1 breast cancer suppression. Therefore, it is suspected that sporadic BLCs exhibit a defect in HR. To test this hypothesis, multiple DNA damage repair assays focused on several types of repair were performed on a group of cell lines classified as sporadic BLCs and on controls. The sporadic BLC cell lines failed to exhibit an overt HR defect. Rather, they exhibited defects in the repair of stalled replication forks, another BRCA1 function. These results provide insight into why clinical trials of poly(ADP-ribose) polymerase (PARP) inhibitors, which require an HR defect for efficacy, have been unsuccessful in sporadic BLCs, unlike cisplatin, which elicits DNA damage that requires stalled fork repair and has shown efficacy in sporadic BLCs.

Heterotaxy syndrome and malrotation: does isomerism influence risk and decision to treat

PURPOSE

Controversy remains regarding the management of the asymptomatic heterotaxy syndrome (HS) patient with suspected intestinal rotational abnormalities. We evaluated the outcomes for our HS population to identify frequency of malrotation and identify characteristics of children who might benefit from expectant management.

METHODS

After IRB approval, a retrospective review of all patients treated for HS at a large tertiary care children's hospital between January 2008 and June 2012 was performed. For the purpose of this paper, malrotation was defined as an operative note that described the presence of Ladd's bands and a narrow mesentery.

RESULTS

Thirty-eight patients with HS were identified, including 18 who underwent abdominal exploration. Left atrial isomerisation (LAI) was identified in 13 individuals, and right atrial isomerisation (RAI) was noted in 25. The rate of surgical intervention did not vary between the 2 groups (54%). Malrotation was found in 8 patients: one with LAI and 7 with RAI. This difference in incidence was statistically significant (p=0.04).

CONCLUSION

These data suggest that the direction of atrial isomerisation influences the likelihood of true malrotation, where RAI patients are more likely to be malrotated. Given the inherent risk of surgery on this medically fragile patient population, surgeons should consider expectant management for asymptomatic LAI patients.

Cystic biliary atresia: a wolf in sheep's clothing

Neonatal obstructive jaundice is frequently explained by biliary atresia (BA) or the presence of a choledochal cyst (CC). Cystic biliary atresia (CBA) has been a proposed as a subtype of BA with projected improved outcomes. We aimed to characterize these lesions further. We conducted an Institutional Review Board-approved review of all patients treated for obstructive jaundice at our tertiary children's hospital over 10 years. Over the decade we evaluated 91 children with obstructive jaundice: 13 CBA, 52 BA, and 26 CC. Patients with isolated CBA and BA were diagnosed significantly earlier than those with CC (15.9, 54, and 281 days, respectively; P = 0.0001). There was a significant delay between diagnosis and surgical intervention for patients with CBA compared with BA: 17 days versus 5.7 days (P = 0.004). There was no difference in rate of transplant between CBA and BA (31 vs. 50%; P = 0.35). The time from surgery until transplant was 13.9 and 18.6 months for CBA and BA, respectively (P = 0.62). Although radiographically similar to CC, CBA behaves similarly to isolated BA. Delay in recognition and surgical treatment may affect outcomes and lead to an increased incidence of liver failure. The presence of a cystic biliary malformation in the setting of neonatal jaundice should be regarded as CBA until proven otherwise.

Assessing insect responses to climate change: What are we testing for? Where should we be heading?

To understand how researchers are tackling globally important issues, it is crucial to identify whether current research is comprehensive enough to make substantive predictions about general responses. We examined how research on climate change affecting insects is being assessed, what factors are being tested and the localities of studies, from 1703 papers published between 1985 and August 2012. Most published research (64%) is generated from Europe and North America and being dedicated to core data analysis, with 29% of the studies analysed dedicated to Lepidoptera and 22% Diptera: which are well above their contribution to the currently identified insect species richness (estimated at 13% and 17% respectively). Research publications on Coleoptera fall well short of their proportional contribution (19% of publications but 39% of insect species identified), and to a lesser extent so do Hemiptera, and Hymenoptera. Species specific responses to changes in temperature by assessing distribution/range shifts or changes in abundance were the most commonly used methods of assessing the impact of climate change on insects. Research on insects and climate change to date is dominated by manuscripts assessing butterflies in Europe, insects of economic and/or environmental concern in forestry, agriculture, and model organisms. The research on understanding how insects will respond to a rapidly changing climate is still in its infancy, but the current trends of publications give a good basis for how we are attempting to assess insect responses. In particular, there is a crucial need for broader studies of ecological, behavioural, physiological and life history responses to be addressed across a greater range of geographic locations, particularly Asia, Africa and Australasia, and in areas of high human population growth and habitat modification. It is still too early in our understanding of taxa responses to climate change to know if charismatic taxa, such as butterflies, or disease vectors, including Diptera, can be used as keystone taxa to generalise other insect responses to climate change. This is critical as the basic biology of most species is still poorly known, and dominant, well studied taxa may show variable responses to climate change across their distribution due to regional biotic and abiotic influences. Indeed identifying if insect responses to climate change can be generalised using phylogeny, functional traits, or functional groups, or will populations and species exhibit idiosyncratic responses, should be a key priority for future research.

Laparoscopic versus open reduction of intussusception in children: experience over a decade

BACKGROUND

Intussusception is a common cause of bowel obstruction in children, which sometimes necessitates operative reduction and or resection. We report our series of patients with intussusception who were treated laparoscopically (LAP group) compared with exploratory laparotomy (OPEN group).

SUBJECTS AND METHODS

After institutional review board approval, a retrospective review was performed evaluating outcomes for patients requiring surgical reduction of intussusception over a 10-year period. Analysis was based on intent to treat, and technique of exploration was surgeon's choice. Data were analyzed with the Wilcoxon rank sum test and chi-squared test where appropriate. P≤.05 was considered significant.

RESULTS

During the time period studied, there were 92 patients treated surgically for intussusception: 65 LAP and 27 OPEN. Conversion to the open procedure was required for 21 patients in the LAP group, and of those, 6 required bowel resection. Seven of the patients who were started in the OPEN group ultimately required bowel resection. Operative time, length of hospital stay, time to full feeds, and total days of narcotics were all significantly shorter for the LAP group compared with the OPEN group (P=.003, P=.001, P=.001, and P=.004, respectively). A pathologic lead point was found in 14% of LAP and 15% of OPEN cases. In a subset analysis, 33% of patients who were converted from the LAP group to the open procedure had a pathologic lead point. Complication rates between the LAP and OPEN groups were comparable.

CONCLUSIONS

Laparoscopy appears to be a safe and effective technique for reducing intussusception in children. The laparoscopic cases had shorter operative time, shorter time to full feeds, lower requirement for intravenous narcotics, and earlier discharges.

An alternative approach for management of the congenital giant inguinal hernia in neonates

Whereas inguinal hernias are commonly encountered in the neonatal population, giant hernias containing the entire small bowel and with complete inguinal floor disruption are significantly less common. These cases present clinical and technical challenges with the obliteration of normal anatomy and an attenuation of the expected abdominal domain. There is a scant literature available describing these hernias or their management in neonates. In this case report, we describe a neonate who presented with a giant unilateral inguinal scrotal hernia complicated by in utero perforation. This was managed by open herniorrhaphy, orchidopexy, and diagnostic laparoscopy.

BRCA1 is required for postreplication repair after UV-induced DNA damage

BRCA1 contributes to the response to UV irradiation. Utilizing its BRCT motifs, it is recruited during S/G2 to UV-damaged sites in a DNA replication-dependent but nucleotide excision repair (NER)-independent manner. More specifically, at UV-stalled replication forks, it promotes photoproduct excision, suppression of translesion synthesis, and the localization and activation of replication factor C complex (RFC) subunits. The last function, in turn, triggers post-UV checkpoint activation and postreplicative repair. These BRCA1 functions differ from those required for DSBR.

Management of cryptorchidism and gastroschisis

BACKGROUND

Cryptorchidism is commonly associated with gastroschisis. Management of the undescended testes varies with regard to technique and timing of orchidopexy. To evaluate the appropriate timing of and procedure for orchidopexy in patients with gastroschisis, we reviewed our experience.

METHODS

Male neonates admitted between January 1999 and September 2010 with gastroschisis were reviewed. This retrospective study was conducted after institutional review board approval. Testis location at birth was recorded, and outcomes for those with undescended testes were analyzed.

RESULTS

Sixty-two males with gastroschisis were identified, and 24 had cryptorchidism (38.7%) affecting 31 testes. All babies had an initial watch-and-wait approach without any attempt at orchidopexy during gastroschisis closure. Those with extraabdominal testes at birth had the testicle repositioned in the abdomen before gastroschisis closure. Mean follow-up was 27.3 months. At follow-up, 54.8% of the testes relocated without intervention and 38.7% required orchidopexy. Laparoscopy was used in 5 patients to perform the orchidopexy. A total of 3 testes required orchiectomy secondary to atrophy, one of which had previously undergone an orchidopexy. Two of the orchiectomies were performed laparoscopically.

CONCLUSION

The watch-and-wait approach for cryptorchidism in gastroschisis is safe and appropriate, with a high rate of spontaneous migration during the first year of life and greater than 90% testes viable at follow-up. Laparoscopy is a safe and feasible option for management of undescended testes that remain intraabdominal at follow-up.

Absorbable versus nonabsorbable mesh repair of congenital diaphragmatic hernias in a growing animal model

INTRODUCTION

The repair of large congenital diaphragmatic hernia frequently results in patch disruption and recurrence as patients grow in size. Absorbable meshes allow for ingrowth of endogenous tissue as they are degraded, providing a more natural and durable repair. The aim of this study was to compare the characteristics of the new diaphragmatic tissue between an absorbable biologic mesh and a nonabsorbable mesh for repairing diaphragmatic hernia in a growing animal model.

METHODS

The left hemi-diaphragm of twenty 2-month-old Yucatan pigs was nearly completely resected. Small intestinal submucosa (SIS; Cook Biotech, Lafayette, IN) and expanded polytetrafluoroethylene (ePTFE; W.L. Gore & Associates, Flagstaff, AZ) were randomly assigned to cover the defect in 10 animals each, and were survived for 6 months. During necropsy, newly formed diaphragmatic tissue was evaluated and compared between the two groups.

RESULTS

At necropsy, the animals had tripled their weight. Patch disruption and herniation occurred in 3 animals in the ePTFE group and none in the SIS group. The SIS mesh had better integration to the chest wall (2.8 ± 0.2 versus 1.3 ± 0.3), more muscle growth within the newly formed diaphragmatic tissue (1.9 ± 0.2 versus 0.4 ± 0.2), and less fibrotic tissue (2.1 ± 0.5 versus 3.4 ± 0.4) than ePTFE. There was no difference between SIS and ePTFE in terms of adhesion scores to the lung (2 ± 0.4 versus 2.4 ± 0.4) and liver (1.8 ± 0.3 versus 2.2 ± 0.5).

CONCLUSION

SIS allows for tissue ingrowth from surrounding tissue as it degrades, providing a more durable repair with 30% less incidence of herniation in a porcine model. As the diaphragm grows, SIS resulted in a more natural repair of the defect with more tissue growth, better tissue integration, and a comparable adhesion formation to ePTFE.

Bedside placement of an aortic occlusion balloon to control a ruptured aorto-esophageal fistula in a small child

A child had a percutaneous endoscopic gastrostomy tube removed by transecting it at skin level. The internal portion ("the bolster") was allowed to pass in the GI tract. She subsequently had odynophagia. Magnetic resonance imaging identified a foreign body within the lower thoracic esophagus. During esophagoscopy, the bolster was removed. The following morning, she had massive hematemesis with cardiovascular collapse. As an emergent maneuver, an intra-aortic balloon was percutaneously deployed at the bedside without fluoroscopic guidance. This temporized the exsanguination. Subsequent intraoperative aortography confirmed an aortoesophageal fistula. A stent-graft was deployed with immediate hemodynamic stabilization. She later underwent esophageal resection and recovered well.