Frequency and Nature of Genomic Alterations in ERBB2-Altered Urothelial Bladder Cancer

BACKGROUND

Human epidermal growth factor-2 (HER2) overexpression is an oncogenic driver in many solid tumors, including urothelial bladder cancer (UBC). In addition, activating mutations in the ERBB2 gene have been shown to play an oncogenic role similar to ERBB2 amplification.

OBJECTIVE

To describe and compare the frequency and nature of genomic alterations (GA) of ERBB2-altered (mutations, amplification) and ERBB2 wild-type UBC.

PATIENTS AND METHODS

Using a hybrid capture-based comprehensive profiling assay, 9518 UBC cases were grouped by ERBB2 alteration and evaluated for all classes of genomic alterations (GA), tumor mutational burden (TMB), microsatellite instability (MSI), genome-wide loss of heterozygosity (gLOH), and genomic mutational signature. PD-L1 expression was measured by immunohistochemistry (Dako 22C3). Categorical statistical comparisons were performed using Fisher's exact tests.

RESULTS

A total of 602 (6.3%) UBC cases featured ERBB2 extracellular domain short variant (SV) GA (ECDmut+), 253 (2.7%) cases featured ERBB2 kinase domain SV GA (KDmut+), 866 (9.1%) cases had ERBB2 amplification (amp+), and 7797 (81.9%) cases were ERBB2 wild-type (wt). European genetic ancestry of ECDmut+ was higher than ERBB2wt. Numerous significant associations were observed when comparing GA by group. Notably among these, CDKN2A/MTAP loss were more frequent in ERBB2wt versus ECDmut+ and amp+. ERBB3 GA were more frequent in ECDmut+ and KDmut+ than ERBB2wt. TERT GA were more frequent in ECDmut+, KDmut+, and amp+ versus ERBB2wt. TOP2A amplification was significantly more common in ECDmut+ and amp+ versus ERBB2wt, and TP53 SV GA were significantly higher in ERBB2 amp+ versus ERBB2wt. Mean TMB levels were significantly higher in ECDmut+, KDmut+, and amp+ than in ERBB2wt. Apolipoprotein B mRNA-editing enzyme, catalytic polypeptides (APOBEC) signature was more frequent in ECDmut+, KDmut+, and amp+ versus ERBB2wt. No significant differences were observed in PD-L1 status between groups, while gLOH-high status was more common in amp+ versus ERBB2wt. MSI-high status was more frequent in KDmut+ versus ERBB2wt, and in ERBB2wt than in amp+.

CONCLUSIONS

We noted important differences in co-occurring GA in ERBB2-altered (ECDmut+, KDmut+, amp+) versus ERBB2wt UBC, as well as higher mean TMB and higher APOBEC mutational signature in the ERBB2-altered groups. Our results can help refine future clinical trial designs and elucidate possible response and resistance mechanisms for ERBB2-altered UBC.

Beyond regulatory compliance: evaluating radiology artificial intelligence applications in deployment

The implementation of artificial intelligence (AI) applications in routine practice, following regulatory approval, is currently limited by practical concerns around reliability, accountability, trust, safety, and governance, in addition to factors such as cost-effectiveness and institutional information technology support. When a technology is new and relatively untested in a field, professional confidence is lacking and there is a sense of the need to go above the baseline level of validation and compliance. In this article, we propose an approach that goes beyond standard regulatory compliance for AI apps that are approved for marketing, including independent benchmarking in the lab as well as clinical audit in practice, with the aims of increasing trust and preventing harm.

The Application of Digital Frailty Screening to Triage Nonhealing and Complex Wounds

OBJECTIVE

We investigated the association between the complexity of diabetic foot ulcers (DFUs) and frailty.

RESEARCH DESIGN AND METHODS

Individuals (n = 38) with Grade 2 Wagner DFU were classified into 3 groups based on the Society for Vascular Surgery risk-stratification for major limb amputation as Stage 1 at very low risk (n = 19), Stage 2 at low risk (n = 9), and Stage 3 to 4 at moderate-to-high risk (n = 10) of major limb amputation. Frailty status was objectively assessed using a validated digital frailty meter (FM). The FM works by quantifying weakness, slowness, rigidity, and exhaustion over a 20-second repetitive elbow flexion-extension exercise using a wrist-worn sensor. FM generates a frailty index (FI) ranging from 0 to 1; higher values indicate progressively greater severity of frailty. Skin perfusion pressure (SPP), albumin, and tissue oxygenation level (SatO2) were also measured. One-way analysis of variance (ANOVA) was used to identify group effect for wound complexity. Pearson's correlation coefficient was used to assess the associations with frailty and clinical endpoints.

RESULTS

Frailty index was higher in Stage 3 and 4 as compared to Stage 1 (d = 1.4, P < .01) and Stage 2 (d = 1.2, P < .01). Among assessed frailty phenotypes, exhaustion was correlated with SPP (r = -0.63, P < .01) and albumin (r = -0.5, P < .01).

CONCLUSION

Digital biomarkers of frailty may predict complexity of DFU and thus triage individuals who can be treated more simply in their primary clinic versus higher risk patients who require prompt referral to multidisciplinary, more complex care.

Measurement of Electron-Neutrino Charged-Current Cross Sections on ^{127}I with the COHERENT NaIνE Detector

Using an 185-kg NaI[Tl] array, COHERENT has measured the inclusive electron-neutrino charged-current cross section on ^{127}I with pion decay-at-rest neutrinos produced by the Spallation Neutron Source at Oak Ridge National Laboratory. Iodine is one the heaviest targets for which low-energy (≤50  MeV) inelastic neutrino-nucleus processes have been measured, and this is the first measurement of its inclusive cross section. After a five-year detector exposure, COHERENT reports a flux-averaged cross section for electron neutrinos of 9.2_{-1.8}^{+2.1}×10^{-40}  cm^{2}. This corresponds to a value that is ∼41% lower than predicted using the MARLEY event generator with a measured Gamow-Teller strength distribution. In addition, the observed visible spectrum from charged-current scattering on ^{127}I has been measured between 10 and 55 MeV, and the exclusive zero-neutron and one-or-more-neutron emission cross sections are measured to be 5.2_{-3.1}^{+3.4}×10^{-40} and 2.2_{-0.5}^{+0.4}×10^{-40}  cm^{2}, respectively.

Urothelial Bladder Cancer: Genomic Alterations in Fibroblast Growth Factor Receptor

BACKGROUND AND OBJECTIVE

Genomic alterations in fibroblast growth factor receptor (FGFR) genes have been linked to a reduced response to immune checkpoint inhibitors. Some of the immune microenvironment of urothelial bladder cancer (UBC) could be distorted because of the inhibition of interferon signaling pathways. We present a landscape of FGFR genomic alterations in distorted UBC to evaluate the immunogenomic mechanisms of resistance and response.

METHODS

There were 4035 UBCs that underwent hybrid, capture-based comprehensive genomic profiling. Tumor mutational burden was determined in up to 1.1 Mbp of sequenced DNA and microsatellite instability was determined in 114 loci. Programmed death ligand expression in tumor cells was assessed by immunohistochemistry (Dako 22C3).

RESULTS

The FGFR tyrosine kinases were altered in 894 (22%) UBCs. The highest frequency of alterations was in FGFR genomic alterations with FGFR3 at 17.4% followed by FGFR1 at 3.7% and FGFR2 at 1.1%. No FGFR4 genomic alterations were identified. The age and sex distribution were similar in all groups. Urothelial bladder cancers that featured FGFR3 genomic alterations were associated with lower driver genomic alterations/tumors. 14.7% of the FGFR3 genomic alterations were FGFR3 fusions. Other findings included a significantly higher frequency of ERBB2 amplification in FGFR1/2-altered UBCs compared with FGFR3-altered UBCs. Urothelial bladder cancers with FGFR3 genomic alterations also had the highest frequency of the activating mTOR pathway. FGFR3-altered UBCs also featured significantly higher frequencies of biomarkers associated with a lack of response to immune checkpoint inhibitors including a lower tumor mutational burden, lower programmed death-ligand 1 expression, and higher frequencies of genomic alterations in MDM2. Also linked to IO drug resistance, CDKN2A/B loss and MTAP loss were observed at a higher frequency in FGFR3-driven UBC.

CONCLUSIONS

An increased frequency of genomic alterations is observed in UBC FGFR. These have been linked to immune checkpoint inhibitor resistance. Clinical trials are needed to evaluate UBC FGFR-based biomarkers prognostic of an immune checkpoint inhibitor response. Only then can we successfully incorporate novel therapeutic strategies into the evolving landscape of UBC treatment.

Abstract 963: Clinical impact of MTAP status in advanced cholangiocarcinoma: Genomic profile and response to treatment

Background: MTAP-loss is an emerging biomarker guiding druggable targets in cholangiocarcinoma and almost exclusively occurs in the setting of 9p21 loss, which has itself been associated with reduced IO responsiveness and poorer survival outcomes on a pan-cancer analysis. We sought to understand the clinical impact of MTAP status on treatment and survival outcomes, in a clinical cohort of molecularly characterized advanced cholangiocarcinoma patients.

Methods: We analyzed advanced cholangiocarcinoma patients treated and evaluated at MD Anderson Cancer Center, tested for MTAP. Clinical information including genomic co-alterations, demographic information, treatment history and response to treatment were retrieved from retrospective medical record review. Comprehensive genomic profiling was performed with FDA-approved assays. Statistical analysis was performed with SPSS24 using Fisher's exact test, multivariate Cox regression and Kaplan-Meyer method for survival analysis.

Results: 71 patients were identified (MTAP loss 31% (22/71); MTAP intact 69% (49/71)); 54,9% (39/71) were females. No significant difference in gender, age or ethnicity was seen between MTAP cohorts.

We found that altered CDKN2A (p&lt;0.01), CDKN2B (p&lt;0.01), and IDH1 (p=0.048) were highly correlated with MTAP loss, while STK11 (p=0.095), a prognostic indicator of IO resistance, also showed a tendency to be a surrogate marker of MTAP loss status. Tumor mutational burden (TMB) was lower in MTAP loss group (2.18 vs. 4.88, p &lt;0.01), but no difference was found in microsatellite instability (MSI) or PD-L1 status between groups.

On multivariate analysis, patients harboring CDKN2A loss were noted to have worse OS compared to those without CDKN2A intact (18.6 vs 29.9 months, 95% CI, p=0.035). No statistically significant difference in OS was observed by MTAP status (25.9 vs. 29.2 months, 95% CI, p=0.168). Other genomic alterations with significant impact on OS were CCNE1 (p&lt;0.01), FGF19 (p=0.04), and MYC (p=0.043).

Treatment with chemotherapy regimens containing Gemcitabine in the first line setting of metastatic disease showed higher disease control rate in the MTAP intact cohort (91.4%) vs. MTAP loss cohort (38.5%) (p&lt;0.01), but no statistically significant difference in response (PR/CR) (p=0.421). Few patients (14/71) received IO in this cohort; no significant difference in IO response was observed by MTAP status (p=0.152).

Conclusions: MTAP loss cholangiocarcinoma has a distinct molecular profile compared with MTAP intact including key differences in co-altered tumor suppressor genes and TMB. To our knowledge, this is the first real-world data describing the clinical and genomic differences in advanced cholangiocarcinoma by MTAP status. Further prospective data are required to validate these

findings.

Citation Format: Cátia F. Gaspar, Natalie Y. Ngoi, Tin Tang, Jeffrey Ross, Dean Pavlick, Gregory Buchold, Shubham Pant, Milind Javle, Jordi Ahnert. Clinical impact of MTAP status in advanced cholangiocarcinoma: Genomic profile and response to treatment [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 963.

Genetic Heterogeneity and Tissue-specific Patterns of Tumors with Multiple PIK3CA Mutations

PURPOSE

To comprehensively characterize tissue-specific and molecular subclasses of multiple PIK3CA (multi-PIK3CA) mutations and assess their impact on potential therapeutic outcomes.

EXPERIMENTAL DESIGN

We profiled a pan-cancer cohort comprised of 352,392 samples across 66 tumor types using a targeted hybrid capture-based next-generation sequencing panel covering at least 324 cancer-related genes. Molecularly defined subgroups, allelic configuration, clonality, and mutational signatures were identified and tested for association with PI3K inhibitor therapeutic response.

RESULTS

Multi-PIK3CA mutations are found in 11% of all PIK3CA-mutant tumors, including 9% of low tumor mutational burden (TMB) PIK3CA-mutant tumors, and are enriched in breast and gynecologic cancers. Multi-PIK3CA mutations are frequently clonal and in cis on the same allele and occur at characteristic positions across tumor types. These mutations tend to be mutually exclusive of mutations in other driver genes, and of genes in the PI3K pathway. Among PIK3CA-mutant tumors with a high TMB, 18% are multi-PIK3CA mutant and often harbor an apolipoprotein B mRNA-editing enzyme, catalytic polypeptide (APOBEC) mutational signature. Despite large differences in specific allele combinations comprising multi-PIK3CA mutant tumors, especially across cancer types, patients with different classes of multi-PIK3CA mutant estrogen receptor-positive, HER2-negative breast cancers respond similarly to PI3K inhibition.

CONCLUSIONS

Our pan-tumor study provides biological insights into the genetic heterogeneity and tissue specificities of multi-PIK3CA mutations, with potential clinical utility to guide PI3K inhibition strategies.

Comprehensive Genomic Profiling of NF2-Mutated Kidney Tumors Reveals Potential Targets for Therapy

Genomic alterations (GA) in NF2 tumor-suppressor gene have been associated with aggressive behavior in kidney tumors. We used comprehensive genomic profiling (CGP) to evaluate the frequencies of NF2 GA in histologic subtypes of kidney tumors and co-occurring GA in other genes and biomarkers. Advanced kidney tumors included 1875 clear cell (ccRCC), 405 papillary (pRCC), 108 chromophobe (chRCC), 171 sarcomatoid (sRCC), 61 collecting duct (cdRCC), 49 medullary (mRCC), 134 unclassified (uRCC), 906 urothelial carcinoma of renal pelvis (UC), and 147 Wilms tumors underwent hybrid-capture based CGP to evaluate all classes of GA. 192 (4.9%) of kidney tumors featured NF2 GA which were predominantly structural variant mutations (89%), followed by copy number alterations (9%). Gender and age were similar between NF2-mutant (NF2mut) and NF2-wild type (NF2wt) cohorts with male preponderance. NF2 GA frequency was highest in cdRCC (30%), sRCC (21%), uRCC (15%), and pRCC (12%) while lowest in ccRCC (3%), UC (3%) Wilms tumor (1%), and chRCC (0%). NF2 mutational status was associated with loss of Ch 22 (P < .001). NF2mut RCC harbored co-occurring GA including CDKN2A, CDKN2B, SETD2, and BAP1. VHL, PBRM1, PTEN, and FGFR3 GA were significantly more frequent in NF2wt than in NF2mut tumors. MTOR pathway GAs were uncommon in NF2mut tumors. No NF2 mutated RCC featured MSI-high or high TMB. sRCC was associated with high PD-L1 expression. PD-L1 SP142 tumoral (P = .04) and immune cells (P = .013) were more frequent in NF2mut as compared to NF2wt group. Among histologic subtypes of RCC, cdRCC, sRCC, pRCC, and uRCC are enriched in NF2 GA. Co-occurrent GA in CDKN2A/B, SETD2, and BAP1 may represent potential therapeutic targets. Higher level of PD-L1 expression in NF2mut cohort suggests that these tumors might be sensitive to immune checkpoint inhibitor therapies.

Genomic landscape of metastatic breast cancer (MBC) patients with methylthioadenosine phosphorylase (MTAP) loss

INTRODUCTION

Homozygous deletion of MTAP upregulates de novo synthesis of purine (DNSP) and increases the proliferation of neoplastic cells. This increases the sensitivity of breast cancer cells to DNSP inhibitors such as methotrexate, L-alanosine and pemetrexed.

MATERIALS AND METHODS

7,301 cases of MBC underwent hybrid-capture based comprehensive genomic profiling (CGP). Tumor mutational burden (TMB) was determined on up to 1.1 Mb of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. Tumor cell PD-L1 expression was determined by IHC (Dako 22C3).

RESULTS

208 (2.84%) of MBC featured MTAP loss. MTAP loss patients were younger (p = 0.002) and were more frequently ER- (30% vs. 50%; p < 0.0001), triple negative (TNBC) (47% vs. 27%; p < 0.0001) and less frequently HER2+ (2% vs. 8%; p = 0.0001) than MTAP intact MBC. Lobular histology and CDH1 mutations were more frequent in MTAP intact (14%) than MTAP loss MBC (p < 0.0001). CDKN2A (100%) and CDKN2B (97%) loss (9p21 co-deletion) were significantly associated with MTAP loss (p < 0.0001). Likely associated with the increased TNBC cases, BRCA1 mutation was also more frequent in MTAP loss MBC (10% vs. 4%; p < 0.0001). As for immune checkpoint inhibitors biomarkers, higher TMB >20 mut/Mb levels in the MTAP intact MBC (p < 0.0001) and higher PD-L1 low expression (1-49% TPS) in the MTAP loss MTAP (p = 0.002) were observed.

CONCLUSIONS

MTAP loss in MBC has distinct clinical features with genomic alterations (GA) affecting both targeted and immunotherapies. Further efforts are necessary to identify alternative means of targeting PRMT5 and MTA2 in MTAP-ve cancers to benefit from the high-MTA environment of MTAP-deficient cancers.

First Probe of Sub-GeV Dark Matter beyond the Cosmological Expectation with the COHERENT CsI Detector at the SNS

The COHERENT Collaboration searched for scalar dark matter particles produced at the Spallation Neutron Source with masses between 1 and 220  MeV/c^{2} using a CsI[Na] scintillation detector sensitive to nuclear recoils above 9  keV_{nr}. No evidence for dark matter is found and we thus place limits on allowed parameter space. With this low-threshold detector, we are sensitive to coherent elastic scattering between dark matter and nuclei. The cross section for this process is orders of magnitude higher than for other processes historically used for accelerator-based direct-detection searches so that our small, 14.6 kg detector significantly improves on past constraints. At peak sensitivity, we reject the flux consistent with the cosmologically observed dark-matter concentration for all coupling constants α_{D}<0.64, assuming a scalar dark-matter particle. We also calculate the sensitivity of future COHERENT detectors to dark-matter signals which will ambitiously test multiple dark-matter spin scenarios.

The time is now: making the case for a UK registry of deployment of radiology artificial intelligence applications

Artificial intelligence (AI)-based healthcare applications (apps) are rapidly evolving, and radiology is a target specialty for their implementation. In this paper, we put the case for a national deployment registry to track the spread of AI apps into clinical use in radiology in the UK. By gathering data on the specific locations, purposes, and people associated with AI app deployment, such a registry would provide greater transparency on their spread in the radiology field. In combination with other regulatory and audit mechanisms, it would provide radiologists and patients with greater confidence and trust in AI apps. At the same time, coordination of this information would reduce costs for the National Health Service (NHS) by preventing duplication of piloting activities. This commentary discusses the need for a UK-wide registry for such apps, its benefits and risks, and critical success factors for its establishment. We conclude by noting that a critical window of opportunity has opened up for the development of a deployment registry, before the current pattern of localised clusters of activity turns into the widespread proliferation of AI apps across clinical practice.

Understanding the tool influence function during sub-aperture belt-on-wheel glass polishing

The tool influence function (TIF) during sub-aperture belt-on-wheel polishing has been evaluated as a function of various process conditions (belt use/wear, dwell time, displacement, belt velocity, and wheel modulus and diameter) on fused silica glass workpieces using C e O ₂ polishing media. TIF spots are circular or elliptical in shape with a largely flat bottom character. The volumetric removal rate varies significantly with belt use (or wear), stabilizing after ∼15m i n of use. A modified Preston model, where the pressure dependence is adjusted using a different scaling of the wheel modulus (E w0.5), largely predicts the volumetric removal rate over the range of process conditions evaluated. The relatively high volumetric removal rate of 30-60m m ³/h using a fixed C e O ₂-in-resin-host belt offers a rapid, and hence, more economical, initial polish of aspheric and freeform optics.

Establishment and Characterization of Advanced Penile Cancer Patient-derived Tumor Xenografts: Paving the Way for Personalized Treatments

BACKGROUND

Systemic treatments for penile squamous cell carcinoma (pSCC) are toxic and inefficient. Patient-based preclinical models are essential to study novel treatments.

OBJECTIVE

To establish a library of patient-derived tumor xenograft (PDX) models of human papillomavirus-positive (HPV⁺) and -negative (HPV^-) pSCC and characterize these at the genomic and histological levels.

DESIGN, SETTING, AND PARTICIPANTS

Eighteen tumor samples from 14 patients with recurrent or metastatic pSCC were implanted in nude mice. A biobank of PDX tumors was established after passaging of patient samples (F0) for three generations (F1, F2, F3) and was characterized using histopathology and targeted next-generation sequencing (tNGS). Single-nucleotide polymorphism fingerprinting was used to confirm PDX genealogy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The engraftment rate, overall growth rate, and pSCC histomorphology were checked for each PDX generation. Staining for p40 (a pSCC marker) and p16 (a surrogate for HPV infection) was performed for F0 samples. The mutational profile according to a validated panel of 96 cancer genes was determined for F0 and F3 samples and compared to a larger tNGS database.

RESULTS AND LIMITATIONS

Including a previously established pilot model, 11 out of 18 tumor samples (61%) successfully engrafted in F1. The mean time from implantation in F1 to completion of F3 was 36 wk (standard deviation 18). Histological fidelity was demonstrated across generations. The patient mutational profiles were preserved in F3 and were representative of 277 pSCC samples in the Foundation Medicine database. The rapid progression of pSCC in patients from our selected high-risk cohort impeded the use of PDXs as avatars.

CONCLUSIONS

We successfully established the first library of 11 PDX models of HPV^- and HPV⁺ pSCC. Our PDX models showed high engraftment rates and histological and genomic fidelity to the tumor tissue of origin. These models may help in paving the way towards the development of novel treatments.

PATIENT SUMMARY

We established 11 animal models based on tumor tissue from patients with penile cancer. These models could play a vital role in selection of novel treatments according to genetic mutations. In the future, therapies with confirmed preclinical effects may have a profound impact on the development of personalized treatments in penile cancer.

Energetic and myocellular pathways in cardiac and skeletal muscle following anthracycline chemotherapy

Background

Anthracycline-related cardiac dysfunction is a recognised consequence of cancer therapies. Here we assess resting cardiac and skeletal muscle energic status as an early mechanistic pathway of myocyte derangement and explore molecular targets of skeletal myocyte metabolism, protein synthesis/degradation and mitochondrial biogenesis signalling.

Methods

We conducted a prospective, mechanistic, observational, longitudinal study of chemotherapy-naive breast cancer patients undergoing anthracycline-based chemotherapy, compared to a healthy control group. 31P-Magnetic Resonance spectroscopy in cardiac and skeletal muscle (phosphocreatine/gamma adenosine triphosphate (PCr/yATP) and inorganic phosphate/phosphocreatine (Pi/PCr) ratios respectively), cardiac magnetic resonance (CMR) imaging inclusive of T1 and T2 mapping, echocardiography-derived global longitudinal strain function, serum NT-pro-BNP and skeletal muscle biopsies from the right vastus lateralis were assessed before and after 3 cycles of Flurouracil, Epirubicin and Cyclophosphamide followed by 3 cycles of Docetaxel. Statistical significance was set at p&lt;0.05.

Results

Twenty-five female breast cancer patients (median age 53 years, range 32–74 years) receiving a mean epirubicin dose 307 mg/m2) and twenty-eight controls (median age 44 years, range 23–65) were recruited. All study assessments in breast cancer patients at pre-chemotherapy stage were comparable to the matched healthy controls. However, following chemotherapy, breast cancer patients demonstrated a small but significant reduction in cardiac function (global longitudinal strain −22.9±3.9 vs −19.1±3.3%, p=0.01 and CMR-derived ejection fraction 65±5 vs 62±4%, p=0.047), a mild increase in CMR-derived indexed left ventricular volumes (end diastolic 65±10 vs 74±11 ml/m2, p=0.014 and end systolic 23±5 vs 28±5 ml/m2, p=0.01) as well as an increase in left ventricular T1 and T2-mapping (1289±29 vs 1321±31 ms, p=0.004 and 50±4 vs 55±7 ms, p=0.027, respectively) and serum NT-Pro-BNP (49±25 vs 108±84 pg/m, p=0.008). After epirubicin, there was significant reduction in cardiac PCr/yATP ratio (2.0±0.7 vs 1.2±0.6, p=0.007) and a significant increase in skeletal muscle Pi/PCr ratio (0.13±0.04 vs 0.22±0.2, p=0.008) – Figure 1.

Following chemotherapy, there was significant upregulation of skeletal myocyte protein synthesis (mammalian target of rapamycin, 0.44±0.4 vs 0.53±0.2, p&lt;0.001) and degradation (Calcium/calmodulin dependent protein kinase II, 1.4±0.7 vs 2.7±1.1, p&lt;0.001), metabolism (peroxisome proliferator-activated receptor gamma, 0.35±0.2 vs 0.60±0.1, p&lt;0.001) and muscle mass regulator myostatin-2 (0.16±0.1 vs 0.24±0.1, p&lt;0.001).

Conclusion

Contemporary doses of epirubicin for breast cancer result in significant reduction of cardiac and skeletal muscle high energy 31P-metabolism alongside skeletal myocellular alterations of protein synthesis and metabolic regulation pathways.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Tenovus ScotlandNHS Grampian Endowment fund

Measurement of the Coherent Elastic Neutrino-Nucleus Scattering Cross Section on CsI by COHERENT

We measured the cross section of coherent elastic neutrino-nucleus scattering (CEvNS) using a CsI[Na] scintillating crystal in a high flux of neutrinos produced at the Spallation Neutron Source at Oak Ridge National Laboratory. New data collected before detector decommissioning have more than doubled the dataset since the first observation of CEvNS, achieved with this detector. Systematic uncertainties have also been reduced with an updated quenching model, allowing for improved precision. With these analysis improvements, the COHERENT Collaboration determined the cross section to be (165_{-25}^{+30})×10^{-40}  cm^{2}, consistent with the standard model, giving the most precise measurement of CEvNS yet. The timing structure of the neutrino beam has been exploited to compare the CEvNS cross section from scattering of different neutrino flavors. This result places leading constraints on neutrino nonstandard interactions while testing lepton flavor universality and measures the weak mixing angle as sin^{2}θ_{W}=0.220_{-0.026}^{+0.028} at Q^{2}≈(50  MeV)^{2}.

Residual neuromuscular blockade in the ICU: a prospective observational study and national survey

Residual neuromuscular blockade is associated with significant morbidity. It has been widely studied in anaesthesia; however, the incidence of residual neuromuscular blockade in patients managed in the ICU is unknown. We conducted a prospective observational study in a tertiary ICU to determine the incidence of residual neuromuscular blockade using quantitative accelerographic monitoring. We tested for residual neuromuscular blockade (defined as a train-of-four ratio < 0.9) before cessation of sedation in anticipation of tracheal extubation. We also surveyed 16 other ICUs in New Zealand to determine their use of neuromuscular monitoring. A total of 191 patients were included in the final analysis. The incidence (95%CI) of residual neuromuscular blockade was 43% (36-50%), with a similar incidence observed in non-postoperative and postoperative patients. There was a lower risk of residual neuromuscular blockade with atracurium than rocuronium (risk ratio (95%CI) of 0.39 (0.12-0.78)) and a higher risk with pancuronium than rocuronium (1.59 (1.06-2.49)). Our survey shows that, in New Zealand ICUs, monitoring of neuromuscular function is rarely carried out before tracheal extubation. When neuromuscular monitoring is undertaken, it is based on individual clinician suspicion and performed using qualitative measurements. No ICU reported using a quantitative monitor or a clinical guideline. The results demonstrate a high incidence of residual neuromuscular blockade in our ICU patients and identify the type of neuromuscular blocking drug as a possible risk factor. Monitoring neuromuscular function before tracheal extubation is not currently the standard of care in New Zealand ICUs. These data suggest that residual neuromuscular blockade may be an under-recognised problem in ICU practice.

Abstract P5-13-02: Serially biopsied BRCA1/2 mutant breast tumors frequently acquire alterations in BRCA1, BRCA2, and CREBBP

Introduction Tumors with alterations in BRCA1 or BRCA2 (BRCAm) are sensitive to poly ADP ribose polymerase inhibitors (PARPi), with significant benefit in ovary, breast, prostate, and pancreatic cancers. Despite strong early responses on PARPi, many patients eventually exhibit relapse. Previous literature has identified BRCA1/2 reversion as a common class of acquired alteration in the resistance setting; however, additional resistance pathways have not been well characterized. Here, we examined 100 BRCAm patients who were profiled with serial biopsy during clinical care to identify possible therapy resistance alterations. Methods Comprehensive genomic profiling (CGP) was carried out in a Clinical Laboratory Improvement Amendments (CLIA)-certified, CAP (College of American Pathologists)-accredited laboratory (Foundation Medicine Inc., Cambridge, MA, USA). Tissue biopsy CGP was performed on FFPE blocks examining at least 324 genes for all classes of alterations (FoundationOne® and FoundationOne® CDx). Liquid biopsy CGP was performed examining at least 62 genes (FoundationACT®, FoundationOne®Liquid).One hundred breast cancer patients with baseline BRCAm were serially profiled with CGP testing during routine clinical care (n=50 tissue then liquid; n=50 tissue for both tests). As a comparator, we examined 1,294 patients without a baseline BRCAm (BRCAwt) profiled with serial biopsy (n = 585 tissue then liquid; n=709 tissue for both tests). Co-occurrence analyses (Fisher’s exact) were run on the full research dataset, including 12,198 breast-biopsied (local) and 16,586 metastatic-biopsied samples. All classes of genomic alterations were included in the analysis. Results Of the serially biopsied samples, 7.2% (100/1,394) had baseline BRCAm. In patients with baseline BRCAm, acquired alterations were frequently observed in BRCA1/2 (17%), ESR1 (16%), TP53 (15%), MYC (12%), CREBBP (10%), RB1 (9%), PIK3CA (9%), and NF1 (5%). To understand if any of these are specific to the BRCAm population, we compared the milieu of acquired alterations to a serially biopsied BRCAwt cohort (n=1,294). While many of the alterations were common and shared across both cohorts, likely due to endocrine therapy use, acquired alterations in BRCA1, BRCA2, and CREBBP were specifically enriched in the BRCAm population (all p&lt;0.005). Acquired BRCA1/2 mutations were predicted reversion mutations and spanned a range of mechanisms, including large deletion/rearrangement events that remove the exon of the truncal mutation, point mutations that change a nonsense BRCA1/2 to a missense event, upstream indels that revert the frame of the truncal BRCA1/2 event, and splice site mutations that lead to a skipping of the truncal BRCA1/2. Of note, a majority of cases with a reversion involved a rearrangement event (9/17; 53%). For patients with a baseline BRCA1/2 short variant mutation, there was a trend towards a higher rate of reversion in BRCA2 v BRCA1 (23.1% v 18.5%, p&gt;0.05). Acquired BRCAm were never observed in cases with baseline deletion of BRCA1/2. The high rate of acquired CREBBP alterations was specific to the BRCAm population (10% BRCAm v 1% BRCAwt; p = 0.0013), suggesting a possible role for CREBBP in platinum or PARPi resistance. Consistent with this, BRCAm and CREBBP significantly co-occur in the metastatic setting (Odds ratio, OR = 1.6; p = 0.016) but not in the local setting (OR = 1.1; p = 0.68). Conclusions Analysis of serially biopsied BRCAm breast cases revealed frequent acquisition of BRCA1/2 reversion mutations and CREBBP alterations that are not frequently observed in BRCAwt samples. Additional studies are warranted to investigate the possible role of CREBBP in PARPi therapy resistance.

Citation Format: Ethan Sokol, Smruthy Sivakumar, Brennan Decker, Jeffrey Ross, Priti Hegde. Serially biopsied BRCA1/2 mutant breast tumors frequently acquire alterations in BRCA1, BRCA2, and CREBBP [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-13-02.

Abstract P3-09-10: NTRK1/2/3 fusions are observed in both secretory and non-secretory breast cancers

Background NTRK1/2/3 kinase fusions are rare oncogenic drivers found in &lt;1% of solid tumors. NTRK fusion-positive (NTRK+) solid tumors have shown meaningful clinical response to small molecule NTRK inhibitors such as entrectinib and larotrectinib, and broad genomic testing will help identify patients (pts) with these rare alterations. NTRK fusions occur more frequently in some cancers than others. For example, NTRK fusions are characteristic of secretory breast cancers (BCa), and it has been posited that non-secretory BCa lack druggable NTRK fusions (PMID: 30707464). However, these conclusions were drawn on limited patient populations. Here we show evidence of NTRK fusions in both secretory and non-secretory breast tumors in the largest real-world cohort of NTRK+ breast tumors reported to date. Methods Comprehensive genomic profiling of at least 324 cancer-related genes, including NTRK1/2/3, was done at Foundation Medicine on de-identified all-comer BCa pts during the course of routine clinical care. Pathology reports and hematoxylin and eosin (H&E) images of NTRK+ breast tumor tissue were examined by a board-certified pathologist for designation of secretory vs. non-secretory phenotype. Results NTRK fusions were identified in 23 BCa specimens. H&E images were available for review in 22 cases, and another was confirmed as secretory via the pathology report. Pathologist review of those 23 cases revealed that NTRK fusions were present in 11 with secretory phenotypes, 11 with non-secretory phenotypes, and 1 with a mixed secretory phenotype. Secretory cases most often harbored a ETV6-NTRK3 fusion (n=7) with additional recurrent fusions seen in TPM3-NTRK1 (n=2) and LMNA-NTRK1 (n=2). Non-secretory breast cancers also harbored ETV6-NTRK3 (n=2), TPM3-NTRK1 (n=1), and LMNA-NTRK1 (n=1) fusions, as well as several unique fusion events that retain the NTRK kinase domain. Conclusions While rare, NTRK fusions occur in a wide variety of tumor types. Within BCa, this includes both secretory and non-secretory phenotypes, with half of the identified alterations occurring in non-secretory BCa. Recurrent events, including ETV6-NTRK3, were observed in both populations. These data support NTRK fusion testing for all BCa pts with both secretory and non-secretory histologic subtypes.

Citation Format: Ethan Sokol, Sophia Maund, Jeffrey Ross, Timothy Wilson. NTRK1/2/3 fusions are observed in both secretory and non-secretory breast cancers [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-09-10.

Abstract P2-08-03: PD-L1 protein expression in relation to Recurrence Score values in early stage ER+HER2- breast cancer

Background: There is interest in exploring neoadjuvant chemotherapy + immune checkpoint inhibitor therapy in stage II-III ER+ breast cancer, but there is no information on correlation between PD-L1 expression and Oncotype DX Recurrence Score (RS) or histologic grade that currently inform patient selection for adjuvant/neoadjuvant chemotherapy. The goal of this study was to assess associations between PD-L1 protein expression, RS, tumor grade, and stromal tumor infiltrating lymphocyte (TIL) score in early stage ER+ cancers. Methods:. Formalin fixed surgical pathology blocks of 213 patients who had RS determination as routine care between 2012 and 2017 were retrieved from Yale Pathology. PD-L1 immunohistochemistry was performed with the SP142 assay by Foundation Medicine, cases with ≥1% tumor infiltrating immune cell positivity in the tumor area were considered PD-L1+. TIL scores were determined prospectively as part of this study by breast pathologists following the international TIL scoring guidelines. We compared PD-L1 expression positivity rates across RS (&lt;11, 11-25, &gt;25) and TIL categories (&lt;10%, 10-29%, &gt;30%), and tumor grade using Wilcoxon and Chi-square tests. Multivariate analysis was performed using logistic regression. Results: Patient characteristics are shown in the table below. PD-L1 results were available for 201, and TIL scores for 203 patients. Overall, 53% of cases were PD-L1+, but expression levels were low, among the positive cases only 14% had positivity ≥ 5%. PD-L1 expression was significantly higher among cases with RS&gt;25 (78% PD-L1+, among these 19% had PD-L1+ ≥5%), compared to RS&lt;11 and RS 11-25 which were similar to each other (overall 48% were PD-L1+, among these 10% had PD-L1 ≥ 5%). PD-L1 positivity also correlated significantly with TIL score, tumor grade and T stage (tumor size). Among cancers with TIL ≥ 30%, 92% were PD-L1+ and 59% of these had PD-L1 ≥5% compared to 42% PD-L1+ (4% with PD-L1 ≥5%) among TIL&lt; 10%. Grade 3 cancers also had higher PD-L1 positivity (82%, among these 22% with PD-L1 &gt; 5%) compared to grade 2 (49% PD-L1+) or 1 tumors (48% PD-L1+, all at 1% level). T2 and T3 tumors also had significantly more frequent PD-L1 expression (67% and 83%, respectively) compared to T1 cancers (48%). There was no correlation between PD-L1 expression and age, nodal status or histology. In multivariate analysis including age, grade, tumor size, histology, nodal status, TIL score and RS, only TIL and RS remained as independent predictors of PDL1 positivity.

Conclusions: Approximately half of early stage ER+ breast cancers were PD-L1+ using the SP142 assay, but expression levels are low with only 14% showing ≥ 5% immune cell staining. PD-L1 expression is significantly more frequent and higher in larger tumors (T2, T3), grade 3 cancers, and in cancers with RS &gt;25. PD-L1 expression also correlates with TIL score but not with histologic type, nodal status or age. These findings suggest that the most chemotherapy sensitive (grade 3, RS&gt; 25), larger ER+ cancers may benefit from immunotherapy added to chemotherapy, similar to triple negative cancers.

n (%)PD-L1 positivePD-L1 negativep-value (Chi-sq)Histology0.9IDC151 (71%)7567ILC53 (25%)2723other9 (4%)54Grade0.02174 (35%)33362110 (53%)5152329 (12%)236Tumor Size0.008T1145 (68%)6374T262 (29%)3919T3/T46 (3%)51Nodal Status0.9N0177 (84%)9077N135 (16%)1716Age (years)range 39-850.8≤5036 (17%)1815&gt;50177 (83%)8979Recurrence Score0.003RS &lt;1180 (37%)3443RS 12-2594 (45%)4543RS &gt;2539 (18%)288TIL Count0.0000008&lt;10%159 (78%)678610-29%30 (15%)263≥30%14 (7%)111PDL1positive (≥1%)107 (53%)negative94 (47%)

Citation Format: Kim RM Blenman, Malini Harigopal, Richard Huang, Emily Reisenbichler, Tao Qing, Eiman Ibrahim, Kamaljeet Singh, Shakti Ramkissoon, Roberts Mustimbo, Jeffrey Ross, Lajos Pusztai. PD-L1 protein expression in relation to Recurrence Score values in early stage ER+HER2- breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-08-03.

A highly virulent variant of HIV-1 circulating in the Netherlands

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log₁₀ increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence.

The risk of miscarriage following surgical treatment of heterotopic extrauterine pregnancies

STUDY QUESTION

What is the risk of loss of a live normally sited (eutopic) pregnancy following surgical treatment of the concomitant extrauterine ectopic pregnancy?

SUMMARY ANSWER

In women diagnosed with heterotopic pregnancies, minimally invasive surgery to treat the extrauterine ectopic pregnancy does not increase the risk of miscarriage of the concomitant live eutopic pregnancy.

WHAT IS KNOWN ALREADY

Previous studies have indicated that surgical treatment of the concomitant ectopic pregnancy in women with live eutopic pregnancies could be associated with an increased risk of miscarriage. The findings of our study did not confirm that.

STUDY DESIGN, SIZE, DURATION

A retrospective observational case–control study of 52 women diagnosed with live eutopic and concomitant extrauterine pregnancies matched to 156 women with live normally sited singleton pregnancies. The study was carried out in three London early pregnancy units (EPUs) covering a 20-year period between April 2000 and November 2019.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All women attended EPUs because of suspected early pregnancy complications. The diagnosis of heterotopic pregnancy was made on ultrasound scan and women were subsequently offered surgical or expectant management.

There were three controls per each case who were randomly selected from our clinical database and were matched for maternal age, mode of conception and gestational age at presentation.

MAIN RESULTS AND THE ROLE OF CHANCE

In the study group 49/52 (94%) women had surgery and 3/52 (6%) were managed expectantly. There were 9/52 (17%, 95% CI 8.2–30.3) miscarriages <12 weeks’ gestation and 9/49 (18%, 95% CI 8.7–32) miscarriages in those treated surgically. In the control group, there were 28/156 (18%, 95% CI 12.2–24.8) miscarriages <12 weeks’ gestation, which was not significantly different from heterotopic pregnancies who were treated surgically [odds ratio (OR) 1.03 95% CI 0.44–2.36]. There was a further second trimester miscarriage in the study group and one in the control group. The live birth rate in the study group was 41/51 (80%, 95% CI 66.9–90.2) and 38/48 (79%, 95% CI 65–89.5) for those who were treated surgically. These results were similar to 127/156 (81%, 95% CI 74.4–87.2) live births in the control group (OR 0.87, 95% CI 0.39–1.94).

LIMITATIONS, REASONS FOR CAUTION

This study is retrospective, and the number of patients is relatively small, which reflects the rarity of heterotopic pregnancies. Heterotopic pregnancies without a known outcome were excluded from analysis.

WIDER IMPLICATIONS OF THE FINDINGS

This study demonstrates that in women diagnosed with heterotopic pregnancies, minimally invasive surgery to treat the extrauterine pregnancy does not increase the risk of miscarriage of the concomitant live eutopic pregnancy. This finding will be helpful to women and their clinicians when discussing the options for treating heterotopic pregnancies.

STUDY FUNDING/COMPETING INTEREST(S)

This work did not receive any funding. None of the authors has any conflict of interest to declare.

TRIAL REGISTRATION NUMBER

Research Registry: researchregistry6430.

2021 European Guideline on the management of proctitis, proctocolitis and enteritis caused by sexually transmissible pathogens

This guideline intents to offer guidance on the diagnosis and management of patients with gastrointestinal symptoms and a suspected sexually transmitted cause. Proctitis is defined as an inflammatory syndrome of the anal canal and/or the rectum. Infectious proctitis can be sexually transmitted via genital-anal mucosal contact, but some also via digital contact and toys. Neisseria gonorrhoeae, Chlamydia trachomatis (including lymphogranuloma venereum), Treponema pallidum and herpes simplex virus are the most common sexually transmitted anorectal pathogens. Shigellosis can be transferred via oral-anal contact and may lead to proctocolitis or enteritis. Although most studies on these infections have concentrated on men who have sex with men (MSM), women having anal intercourse may also be at risk. A presumptive clinical diagnosis of proctitis can be made when there are symptoms and signs, and a definitive diagnosis when the results of laboratory tests are available. The symptoms of proctitis include anorectal itching, pain, tenesmus, bleeding, constipation and discharge in and around the anal canal. The majority of rectal chlamydia and gonococcal infections are asymptomatic and can only be detected by laboratory tests. Therefore, especially when there is a history of receptive anal contact, exclusion of anorectal infections is generally indicated as part of standard screening for sexually transmitted infections (STIs). Condom use does not guarantee protection from STIs, which are often spread without penile penetration. New in this updated guideline is: (i) lymphogranuloma venereum proctitis is increasingly found in HIV-negative MSM, (ii) anorectal Mycoplasma genitalium infection should be considered in patients with symptomatic proctitis after exclusion of other common causations such N. gonorrhoeae, C. trachomatis, syphilis and herpes, (iii) intestinal spirochetosis incidentally found in colonic biopsies should not be confused with syphilis, and (iv) traumatic causes of proctitis should be considered in sexually active patients.

Comprehensive genomic profiling of histologic subtypes of urethral carcinomas

BACKGROUND

Carcinoma of the urethra (UrthCa) is an uncommon Genitourinary (GU) malignancy that can progress to advanced metastatic disease.

METHODS

One hundred twenty-seven metastatic UrthCa underwent hybrid capture-based comprehensive genomic profiling to evaluate all classes of genomic alterations (GA). Tumor mutational burden was determined on up to 1.1 Mbp of sequenced DNA, and microsatellite instability was determined on 114 loci. PD-L1 expression was determined by IHC (Dako 22C3).

RESULTS

Forty-nine (39%) urothelial (UrthUC), 31 (24%) squamous (UrthSCC), 24 (19%) adenocarcinomas NOS (UrthAC), and 12 (9%) clear cell (UrthCC) were evaluated. UrthUC and UrthSCC are more common in men; UrthAC and UrthCC are more common in women. Ages were similar in all 4 groups. GA in PIK3CA were the most frequent potentially targetable GA; mTOR pathway GA in PTEN were also identified. GA in other potentially targetable genes were also identified including ERBB2 (6% in UrthUC, 3% in UrthSCC, and 12% in UrthAC), FGFR1-3 (3% in UrthSCC), BRAF (3% in UrthAC), PTCH1 (8% in UrthCC), and MET (8% in UrthCC). Possibly reflecting their higher GA/tumor status, potential for immunotherapy benefit associated with higher tumor mutational burden and PD-L1 staining levels were seen in UrthUC and UrthSCC compared to UrthAC and UrthCC. Microsatellite instability high status was absent throughout.

CONCLUSIONS

Comprehensive genomic profiling reveals GA that may be predictive of both targeted and immunotherapy benefit in patients with advanced UrthCa and that could potentially be used in future adjuvant, neoadjuvant, and metastatic disease trials.

Cost-effectiveness of mifepristone and misoprostol versus misoprostol alone for the management of missed miscarriage: an economic evaluation based on the MifeMiso trial

OBJECTIVE

To assess the cost-effectiveness of mifepristone and misoprostol (MifeMiso) compared with misoprostol only for the medical management of a missed miscarriage.

DESIGN

Within-trial economic evaluation and model-based analysis to set the findings in the context of the wider economic evidence for a range of comparators. Incremental costs and outcomes were calculated using nonparametric bootstrapping and reported using cost-effectiveness acceptability curves. Analyses were performed from the perspective of the UK's National Health Service (NHS).

SETTING

Twenty-eight UK NHS early pregnancy units.

SAMPLE

A cohort of 711 women aged 16-39 years with ultrasound evidence of a missed miscarriage.

METHODS

Treatment with mifepristone and misoprostol or with matched placebo and misoprostol tablets.

MAIN OUTCOME MEASURES

Cost per additional successfully managed miscarriage and quality-adjusted life years (QALYs).

RESULTS

For the within-trial analysis, MifeMiso intervention resulted in an absolute effect difference of 6.6% (95% CI 0.7-12.5%) per successfully managed miscarriage and a QALYs difference of 0.04% (95% CI -0.01 to 0.1%). The average cost per successfully managed miscarriage was lower in the MifeMiso arm than in the placebo and misoprostol arm, with a cost saving of £182 (95% CI £26-£338). Hence, the MifeMiso intervention dominated the use of misoprostol alone. The model-based analysis showed that the MifeMiso intervention is preferable, compared with expectant management, and this is the current medical management strategy. However, the model-based evidence suggests that the intervention is a less effective but less costly strategy than surgical management.

CONCLUSIONS

The within-trial analysis found that based on cost-effectiveness grounds, the MifeMiso intervention is likely to be recommended by decision makers for the medical management of women presenting with a missed miscarriage.

TWEETABLE ABSTRACT

The combination of mifepristone and misoprostol is more effective and less costly than misoprostol alone for the management of missed miscarriages.

2019 IUSTI-Europe guideline for the management of anogenital warts

This guideline is an update of the 2011 European Guideline for the Management of Anogenital Warts. It is intended to support best practice in the care of patients with anogenital warts by including evidence-based recommendations on diagnosis, treatment, follow-up and advice to patients. It is intended for use by healthcare professionals in sexual healthcare or dermato-venereology clinics in Europe but may be adapted for use in other settings where the management of anogenital warts is undertaken. As a European guideline, recommendations should be adapted according to national circumstances and healthcare systems. Despite the availability of vaccine to prevent HPV types 6 and 11, the cause of >95% anogenital warts, they remain an important and frequent health problem. The previous systematic review of randomized controlled trials for anogenital warts was updated. The changes in the present guideline include the following: Updated background information on the prevalence, natural history and transmission of human papillomavirus (HPV) infection and anogenital warts. Key recommendations for diagnosis and treatment have been graded according to the strength of the recommendation and the quality of supporting evidence. 5-fluorouracil, local interferon and photodynamic therapy have been evaluated and included as potential second-line treatment options. Evidence of the impact of HPV vaccination on the incidence of anogenital warts has been updated.

Exploring overcrowding trends in an inner city emergence department in the UK before and during COVID-19 epidemic

Background

The COVID-19 pandemic and the associated lockdowns have caused significant disruptions across society, including changes in the number of emergency department (ED) visits. This study aims to investigate the impact of three pre-COVID-19 interventions and of the COVID-19 UK-epidemic and the first UK national lockdown on overcrowding within University College London Hospital Emergency Department (UCLH ED). The three interventions: target the influx of patients at ED (A), reduce the pressure on in-patients’ beds (B) and improve ED processes to improve the flow of patents out from ED (C).

Methods

We collected overcrowding metrics (daily attendances, the proportion of people leaving within 4 h of arrival (four-hours target) and the reduction in overall waiting time) during 01/04/2017–31/05/2020. We then performed three different analyses, considering three different timeframes. The first analysis used data 01/04/2017–31/12–2019 to calculate changes over a period of 6 months before and after the start of interventions A-C. The second and third analyses focused on evaluating the impact of the COVID-19 epidemic, comparing the first 10 months in 2020 and 2019, and of the first national lockdown (23/03/2020–31/05/2020).

Results

Pre-COVID-19 all interventions led to small reductions in waiting time (17%, p < 0.001 for A and C; an 9%, p = 0.322 for B) but also to a small decrease in the number of patients leaving within 4 h of arrival (6.6,7.4,6.2% respectively A-C,p < 0.001).

In presence of the COVID-19 pandemic, attendance and waiting time were reduced (40% and 8%; p < 0.001), and the number of people leaving within 4 h of arrival was increased (6%,p < 0.001). During the first lockdown, there was 65% reduction in attendance, 22% reduction in waiting time and 8% increase in number of people leaving within 4 h of arrival (p < 0.001). Crucially, when the lockdown was lifted, there was an increase (6.5%,p < 0.001) in the percentage of people leaving within 4 h, together with a larger (12.5%,p < 0.001) decrease in waiting time. This occurred despite the increase of 49.6%(p < 0.001) in attendance after lockdown ended.

Conclusions

The mixed results pre-COVID-19 (significant improvements in waiting time with some interventions but not improvement in the four-hours target), may be due to indirect impacts of these interventions, where increasing pressure on one part of the ED system affected other parts. This underlines the need for multifaceted interventions and a system-wide approach to improve the pathway of flow through the ED system is necessary.

During 2020 and in presence of the COVID-19 epidemic, a shift in public behaviour with anxiety over attending hospitals and higher use of virtual consultations, led to notable drop in UCLH ED attendance and consequential curbing of overcrowding.

Importantly, once the lockdown was lifted, although there was an increase in arrivals at UCLH ED, overcrowding metrics were reduced. Thus, the combination of shifted public behaviour and the restructuring changes during COVID-19 epidemic, maybe be able to curb future ED overcrowding, but longer timeframe analysis is required to confirm this.

Art boxes supporting parents and infants to share creative interactions at home: an art-based response to improve well-being during COVID-19 restrictions

OBJECTIVES

This article seeks to demonstrate the impact of distributing boxes of art resources and guided activities for vulnerable parents and infants to do together at home.

STUDY DESIGN

Designed in conjunction with the local arts centre and the psychology team at the University of Dundee, the art boxes were a response to planned face-to-face art interventions with families being cancelled due to COVID-19 restrictions. The aim of the art boxes is to encourage parents to make art together with their infants, fostering connection through playful, creative shared experiences. This research is currently being expanded to reach out to new families through referrals from health visitors, family nurses, and charity partners.

METHODS

Data is being collected on how the art boxes are experienced by families using a mixed-methods approach. Families complete feedback cards (online, or using the stamped addressed card included in the box) rating their experience on quantitative scales and providing open comments. Visual data are gathered through parents sharing images with us on social media. An initial sample of 10 participants has been interviewed using semistructured interviews, allowing more in-depth qualitative understanding of their experiences. These preliminary findings are discussed here.

RESULTS

The thematic analysis of initial interviews provided a rich picture of the disconnection families experienced during lockdown, why art boxes may be beneficial to parental well-being, and the mechanisms by which the boxes may help to develop connections for the parent and infant together.

CONCLUSIONS

Preliminary findings show parents reporting feeling more confident and undertaking new activities which they plan to continue. This was of particular importance during lockdown where parents report opportunities for different experiences being more limited. Parent's describe positive playful interactions and reported improvements to their own well-being from doing creative activities together with their child. Analysis of these initial interviews gives a framework of barriers and supports to connection which highlights how art boxes can facilitate connectedness between dyads with the potential to strengthen attachments.

Abstract PD8-01: Comprehensive genomic profiling (CGP) of metastatic invasive lobular carcinomas reveals heterogeneity in immune biomarkers and resistance alterations across biopsy sites

Introduction Metastatic breast cancer is a clinically challenging disease with poor outcomes. Invasive lobular carcinoma (ILC) is a rarer subtype of breast cancer with distinct patterns of metastasis, including frequent GI and female reproductive (FR) metastases (mets). Due to their relative rarity, little is known about the genomic characteristic of ILC across met sites. Here we explore the genomic landscape of 1909 ILC, stratified by met site, with an examination of immune checkpoint inhibitor (ICPI) biomarkers, therapeutic alterations, and resistance mutations.

Methods CGP was carried out at Foundation Medicine with hybrid capture for exons from up to 395 cancer-related genes plus select introns from up to 31 genes (PMID 24142049). Tumor mutational burden (TMB) was determined on 0.8-1.1 Mb (PMID: 28420421). Ventana PD-L1 IC staining (SP142; positive &gt;= 1% staining) was available for a subset of samples. 1071 breast-biopsied and 1909 met-biopsied ILC and 6926 breast-biopsied and 1901 met-biopsied IDC were available for analysis.

Results High TMB (&gt;= 10 muts/mb) and PD-L1 IC staining are associated with response to ICPI. ILC mets overall had a greater rate of high TMB relative to IDC mets (21% v 9%, p = 7E-25) and breast-biopsied (breast) ILC (21% v 10%; p = 9E-15) with the highest frequency in GI (23%) and skin (21%). PD-L1 IC+ rates were lower in ILC mets (18%) relative to IDC mets (34%) and breast ILC (31%), but were variable across sites, with relatively high rates of positivity in GI (48%), skin (29%), and FR (18%) mets, and no positive staining in bone mets (0/37).

Alterations in PIK3CA were higher in ILC mets (58%) relative to IDC mets (34%) and generally exhibited a similar frequency across ILC met sites, with modestly lower prevalence in skin (48%, p = 0.005). Pathogenic alterations in BRCA1/2 were observed in 4.8% of ILC mets overall, with a lower frequency in GI mets (1.3%, p = 0.03).

A comparison of ILC breast biopsies to ILC mets revealed 19 genes with higher prevalence in at least one ILC met site, most with known roles in therapy resistance (eg ESR1, NF1, RB1, KRAS, ERBB2, BRAF), though significant heterogeneity was observed across sites. Met-enriched (ME) alterations were highest in ILC from the liver (71%) and lowest in FR (33%). ERBB2 mutations, which are may be targetable with HER2 kinase inhibitors, were predominantly found in liver mets (21%) with significantly lower prevalence in skin (11%), bone (10%), GI (3%), and FR (3%). ESR1 alterations were common in most ILC sites, with the highest prevalence in liver (26%) and low frequency in FR (4%). While FR ILC harbored few ME alterations, the rare alterations were primarily found in NF1 (5%) and NCOR1 (5%).

Conclusions CGP revealed significant heterogeneity in ILC mets across tissues. ICPI biomarkers were variable across sites with the highest frequency in ILC GI mets, offering additional potential treatment avenues for these tumors. Alterations in PIK3CA were common in ILC mets with high prevalence across sites, suggesting utility for PIK3CA inhibitors. Therapy-resistant alterations were common in ILC mets but varied across sites. Notably, ERBB2 alterations were most prevalent in ILC liver mets, but less common at other sites.

The high prevalence of therapeutic and resistance alterations suggests value in profiling metastatic lesions.

breast_ILCmet_ILCbreast_IDCmet_IDCgi_ILCliver_ILCfemale_repr_ILCbone_ILCskin_ILCsample count (N)1071190969261901154639114268199ICPI biomarkerTMB-H (&gt;=10muts/mb)10.2%21.0%4.4%9.2%23.4%18.9%14.0%19.0%21.1%PDL1-IC+ SP142 (subset)31.5% (39/124)17.8% (38/213)57.3% (480/837)34.2% (54/158)47.6% (10/21)11.6% (8/69)18.2% (2/11)0% (0/37)28.6% (6/21)Therapy AssociatedPIK3CA50.0%57.6%29.3%34.3%59.1%57.3%62.3%60.1%48.2%BRCA1/24.9%4.8%9.2%7.7%1.3%4.1%7.0%5.2%5.5%Met-EnrichedESR1_mut3.8%18.3%2.2%17.0%20.8%25.5%3.5%11.9%7.5%ERBB2_mut9.7%12.5%2.0%2.7%3.2%20.7%2.6%9.7%11.1%ARID1A_mut7.5%12.2%4.0%5.5%14.3%11.4%7.9%9.0%10.6%NF1_mut4.4%8.7%3.5%4.2%5.8%8.5%5.3%10.4%8.0%RB1_mut2.7%6.3%4.3%3.5%7.8%5.9%2.6%4.5%11.6%KRAS2.3%5.5%3.9%3.6%5.2%6.7%2.6%6.3%2.0%PTEN_del3.1%4.1%5.7%4.7%1.9%4.7%4.4%1.9%8.0%FGFR20.7%3.1%2.9%2.6%1.3%4.1%1.8%4.1%2.0%NCOR1_mut1.2%2.9%1.1%1.1%3.2%3.0%5.3%1.9%1.0%SMAD42.0%2.9%1.2%1.9%1.9%4.7%1.8%2.6%1.5%BRAF1.6%2.1%1.2%1.4%0.0%1.4%2.6%4.5%2.5%FOXP1_mut0.4%1.6%0.3%0.3%2.6%1.1%0.0%1.9%1.0%APC_mut0.9%1.4%1.1%1.1%0.6%0.6%1.8%3.4%2.0%SOX90.3%1.3%0.5%0.4%0.0%1.1%0.0%1.5%0.5%CASP8_mut0.0%0.8%0.5%0.5%0.0%1.1%0.9%1.1%1.0%PTPN11_mut0.1%0.7%0.2%0.3%0.0%0.6%1.8%1.5%1.0%TERT_mut0.2%0.6%0.4%0.7%2.6%0.0%0.0%1.1%0.5%ALK_mut0.1%0.4%0.2%0.4%2.6%0.0%0.9%0.4%0.5%KMT2D_RE0.1%0.3%0.4%0.3%1.9%0.2%0.0%0.0%0.5%any_ME32.5%60.1%30.1%42.4%53.9%71.4%33.3%53.4%52.3%

Citation Format: Ethan Sokol, Dexter X Jin, Jeffrey Ross, Garrett M Frampton, Steffi Oesterreich. Comprehensive genomic profiling (CGP) of metastatic invasive lobular carcinomas reveals heterogeneity in immune biomarkers and resistance alterations across biopsy sites [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD8-01.

Abstract PS5-08: Comparison of PD-L1 protein expression between primary tumors and metastatic lesions in triple negative breast cancers

Background: Several recent studies that compared small cohorts of metastatic and primary lesions, suggested substantial heterogeneity in tumor infiltrating lymphocyte count, immune gene expression and PD-L1 protein expression across different metastatic sites and between primary breast cancers and metastasis. Understanding the frequency of PD-L1 positivity rates across different tissue sites can indicate differences in the immune microenvironment and may also guide biopsy site selection. We compared PD-L1 positivity on immune cells and tumor cells in primary and metastatic triple negative breast cancer tumors (TNBC).Methods: A retrospective data analysis of the Foundation Medicine PD-L1 IHC database was conducted on 340 cases of TNBC. PD-L1 positivity was determined by IHC using SP142CDx. Results are reported as percent of PD-L1 stained immune cells (IC) in the tumor area. A tumor was considered PD-L1 positive if ≥ 1% IC stained positive with PD-L1. As an exploratory analysis, PD-L1 positivity of tumor cells (TC) was also assessed. PD-L1 percent positive staining results are reported as means with 95% CI. The proportion of PD-L1 positive and negative IC and TC in primary tumors vs metastatic sites was compared using Chi-Square test. Prism 8 was used for all data analysis.Results: All patients were female, with median age 56 years (range 26-89); 179 samples were from primary tumors and 161 from metastatic lesions, representing 15 different tissue sites. Overall, PD-L1 expression on immune cells was statistically significantly more frequent in primary tumors compared to metastatic sites (63.7% [n=114] vs 42.9% [n=69]), p&lt;0.0001). This was driven by the lower PD-L1 positivity rates in skin (23.8%, 95% CI: 8.22% - 47.2%), liver (17.4%, 95%CI: 5.00% - 38.8%) and bone (16.7%, 95%CI: 2.10% - 48.4%) metastases. Lung (68.8%, 95% CI: 41.3 - 90.0), soft tissues (65.2%, 95% CI: 42.7 - 83.6) and lymph nodes 51.1%, 95% CI (35.8 - 66.3) had PD-L1 % positivity rates similar to primary tumors. PD-L1 expression was rare on tumor cells in both the breast and metastatic sites (8.3% vs 4.3%, p=0.13). Conclusion: We observed substantial heterogeneity in PD-L1 positivity rates across metastatic sites. Lung, soft tissues and lymph node metastases had PD-L1 % positivity rates that were similar to that of primary tumors whereas skin, liver and bone metastases had significantly lower PD-L1 % positivity rates. These results raise the possibility that response to immune therapy could depend on the location and the PD-L1 positivity of the metastatic site. Limited current experience in breast cancer is not sufficient to correlate tumor response with PD-L1 expression in metastases, but as more patients receive treatment, this could be examined in the future.

Table 1: Sample Characteristics and % PD-L1 positivity on immune cellsSample typeTotal N (%)N PD-L1 positive (%, 95% CI)Primary Tumor179 (52.6)114 (63.7%, 56.2% - 70.7%)Metastatic Lesion161 (47.4)69 (42.9%, 35.1% - 50.9%)Sites of MetastasesN (% of metastatic samples)N PD-L1 positive (%, 95% CI)Lung16 (10.0)11 (68.8%, 41.3% - 90.0%)Soft Tissues23 (14.3)15 (65.2%, 42.7% - 83.6%)Lymph Nodes45 (28.0)23 (51.1%, 35.8% - 66.3%)Skin21 (13.0)5 (23.8%, 8.22% - 47.2%)Liver23 (14.3)4 (17.4%, 5.00% - 38.8%)Bone12 (7.5)2 (16.7%, 2.10% - 48.4%)Brain9 (5.6)5Mediastinum4 (2.5)1Pleura2 (1.2)0Muscle1 (&lt;1)0Omentum1 (&lt;1)1Ovary1 (&lt;1)0Pelvis1 (&lt;1)0Retroperitoneum1 (&lt;1)0Adrenal Gland1 (&lt;1)1

Table 2: Comparison of PD-L1 positivity in primary versus metastatic sitesTissuePDL1+ Immune CellPDL1- Immune CellP valuePDL1+ Tumor CellPDL- Tumor CellP valuePrimary114650.0001151640.1313Metastasis69927154

Citation Format: Mariya Rozenblit, Richard Huang, Natalie Danziger, Brian Alexander, Shakti Ramkissoon, Kim Blenman, Jeffrey Ross, David Rimm, Lajos Pusztai. Comparison of PD-L1 protein expression between primary tumors and metastatic lesions in triple negative breast cancers [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS5-08.

Targetable BRAF and RAF1 Alterations in Advanced Pediatric Cancers

RAF family protein kinases signal through the MAPK pathway to orchestrate cellular proliferation, survival, and transformation. Identifying BRAF alterations in pediatric cancers is critically important as therapeutic agents targeting BRAF or MEK may be incorporated into the clinical management of these patients. In this study, we performed comprehensive genomic profiling on 3,633 pediatric cancer samples and identified a cohort of 221 (6.1%) cases with known or novel alterations in BRAF or RAF1 detected in extracranial solid tumors, brain tumors, or hematological malignancies. Eighty percent (176/221) of these tumors had a known-activating short variant (98, 55.7%), fusion (72, 40.9%), or insertion/deletion (6, 3.4%). Among BRAF altered cancers, the most common tumor types were brain tumors (74.4%), solid tumors (10.8%), hematological malignancies (9.1%), sarcomas (3.4%), and extracranial embryonal tumors (2.3%). RAF1 fusions containing intact RAF1 kinase domain (encoded by exons 10-17) were identified in seven tumors, including two novel fusions TMF1-RAF1 and SOX6-RAF1. Additionally, we highlight a subset of patients with brain tumor with positive clinical response to BRAF inhibitors, demonstrating the rationale for incorporating precision medicine into pediatric oncology. IMPLICATIONS FOR PRACTICE: Precision medicine has not yet gained a strong foothold in pediatric cancers. This study describes the landscape of BRAF and RAF1 genomic alterations across a diverse spectrum of pediatric cancers, primarily brain tumors, but also encompassing melanoma, sarcoma, several types of hematologic malignancy, and others. Given the availability of multiple U.S. Food and Drug Administration-approved BRAF inhibitors, identification of these alterations may assist with treatment decision making, as described here in three cases of pediatric cancer.

Association of body mass index with immune recovery, virological failure and cardiovascular disease risk among people living with HIV

OBJECTIVES

We conducted a longitudinal cohort analysis to evaluate the association of pre-treatment body mass index (BMI) with CD4 recovery, virological failure (VF) and cardiovascular risk disease (CVD) markers among people living with HIV (PLHIV).

METHODS

Participants who were enrolled between January 2003 and March 2019 in a regional Asia HIV cohort with weight and height measurements prior to antiretroviral therapy (ART) initiation were included. Factors associated with mean CD4 increase were analysed using repeated-measures linear regression. Time to first VF after 6 months on ART and time to first development of CVD risk markers were analysed using Cox regression models. Sensitivity analyses were done adjusting for Asian BMI thresholds.

RESULTS

Of 4993 PLHIV (66% male), 62% had pre-treatment BMI in the normal range (18.5-25.0 kg/m² ), while 26%, 10% and 2% were underweight (< 18.5 kg/m² ), overweight (25-30 kg/m2) and obese (> 30 kg/m² ), respectively. Both higher baseline and time-updated BMI were associated with larger CD4 gains compared with normal BMI. After adjusting for Asian BMI thresholds, higher baseline BMIs of 23-27.5 and > 27.5 kg/m² were associated with larger CD4 increases of 15.6 cells/µL [95% confidence interval (CI): 2.9-28.3] and 28.8 cells/µL (95% CI: 6.6-50.9), respectively, compared with normal BMI (18.5-23 kg/m² ). PLHIV with BMIs of 25-30 and > 30 kg/m² were 1.27 times (95% CI: 1.10-1.47) and 1.61 times (95% CI: 1.13-2.24) more likely to develop CVD risk factors. No relationship between pre-treatment BMI and VF was observed.

CONCLUSIONS

High pre-treatment BMI was associated with better immune reconstitution and CVD risk factor development in an Asian PLHIV cohort.

Virological failure and HIV drug resistance among adults living with HIV on second-line antiretroviral therapy in the Asia-Pacific

OBJECTIVES

To assess second-line antiretroviral therapy (ART) virological failure and HIV drug resistance-associated mutations (RAMs), in support of third-line regimen planning in Asia.

METHODS

Adults > 18 years of age on second-line ART for ≥ 6 months were eligible. Cross-sectional data on HIV viral load (VL) and genotypic resistance testing were collected or testing was conducted between July 2015 and May 2017 at 12 Asia-Pacific sites. Virological failure (VF) was defined as VL > 1000 copies/mL with a second VL > 1000 copies/mL within 3-6 months. FASTA files were submitted to Stanford University HIV Drug Resistance Database and RAMs were compared against the IAS-USA 2019 mutations list. VF risk factors were analysed using logistic regression.

RESULTS

Of 1378 patients, 74% were male and 70% acquired HIV through heterosexual exposure. At second-line switch, median [interquartile range (IQR)] age was 37 (32-42) years and median (IQR) CD4 count was 103 (43.5-229.5) cells/µL; 93% received regimens with boosted protease inhibitors (PIs). Median duration on second line was 3 years. Among 101 patients (7%) with VF, CD4 count > 200 cells/µL at switch [odds ratio (OR) = 0.36, 95% confidence interval (CI): 0.17-0.77 vs. CD4 ≤ 50) and HIV exposure through male-male sex (OR = 0.32, 95% CI: 0.17-0.64 vs. heterosexual) or injecting drug use (OR = 0.24, 95% CI: 0.12-0.49) were associated with reduced VF. Of 41 (41%) patients with resistance data, 80% had at least one RAM to nonnucleoside reverse transcriptase inhibitors (NNRTIs), 63% to NRTIs, and 35% to PIs. Of those with PI RAMs, 71% had two or more.

CONCLUSIONS

There were low proportions with VF and significant RAMs in our cohort, reflecting the durability of current second-line regimens.

Abstract 1017: RICTOR/mTOR signaling regulates novel immune checkpoints in non-small cell lung cancer (NSCLC)

Background: RICTOR is a critical component of the mTOR2 complex. Through activation of AKT, SGK1, PKC and other downstream pathways, the RICTOR/mTOR signaling is essential in controlling cell survival, proliferation, metabolism, migration, protein degradation and cytoskeleton functions. Moreover, our recent work implicates that RICTOR amplification may define a unique subtype of NSCLC that can potentially be targeted by mTOR1/2 inhibitors. Additionally, previous evidence also suggest that the PI3K/AKT/mTOR pathway may be involved in immune regulation.

Immunotherapy targeting PD-1/PD-L1 has significantly shifted the treatment landscape in NSCLC. PD-1/PD-L1 belongs to the B7 family of ligands and CD28 family of receptors, which play crucial roles in the regulation of T-cell responses. B7x, HHLA2 and B7-H3 are recently discovered B7 family ligands, which function as T-cell co-inhibitory molecules. These new immune checkpoints are widely expressed in NSCLC and in particular, these alternative immune checkpoints are commonly found in PD-L1 negative tumors. In the current study, we investigated the potential roles of the RICTOR/mTOR signaling on immune modulation, especially the regulation of immune checkpoints.

Results: Using multiple RICTOR amplified NSCLC cells lines (H23, H1703 and H1734), we found that knockdown of RICTOR by siRNA or inducible shRNA resulted in decreased whole lysate and cell surface PD-L1 and HHLA-2 expression but not B7x or B7-H3. RICTOR knockdown can also downregulate IFN-gamma induced PD-L1 expression. Moreover, inducible RICTOR overexpression upregulates PD-L1 levels and also modestly HHLA2 expression. Our preliminary data also indicate that this regulation is likely occurring at a post-transcriptional level. In addition to potential modulation of immune checkpoint molecules, preliminary analysis of 14,698 NSCLC cases indicate that tumors with RICTOR amplification more often have higher levels of tumor mutation burden (TMB) than other lung cancers: the mean TMB was 14.9 mut/Mb in RICTOR-amplified vs 9.2 mut/Mb in non-amplified cases. TMB is a surrogate for increased number of expressed tumor neoantigens and is an important biomarker for response to immune checkpoint inhibitors.

Conclusion: Our study provides new insight into the regulation of the tumor immune microenvironment by RICTOR/mTOR signaling. This may pave the way for designing or improving immunotherapeutic strategies in lung cancer by exploiting the novel immune escape mechanisms in these tumors.

Citation Format: Mariam Alexander, Ni Fan, Xiaoxin Ren, Jeffrey Ross, Hao Wang, Feng Wang, Balazs Halmos, Roman Perez-Soler, Xingxing Zang, Haiying Cheng. RICTOR/mTOR signaling regulates novel immune checkpoints in non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1017.

Tumor mutational burden and driver mutations: Characterizing the genomic landscape of pediatric brain tumors

BACKGROUND

Tumor mutational burden (TMB) and driver mutations are potential biomarkers to guide targeted therapy selection. Malignant gliomas with high TMB in children may preferentially benefit from treatment with immune checkpoint inhibitors (ICPIs). Higher TMB may relate to lower incidence of driver mutations, but this relationship has not been studied in pediatric brain tumors.

PROCEDURE

Comprehensive genomic profiling was performed on 723 pediatric (≤21 years) brain tumor samples using DNA extracted from formalin-fixed paraffin-embedded tissue. TMB was calculated as mutations per megabase and categorized as low (0-6), intermediate (6-20), or high (>20). Analysis included 80 clinically relevant driver mutations; genomic alterations known to confer a selective growth advantage.

RESULTS

Of 723 brain tumors, TMB was low in 91.8%, intermediate in 6.1%, and high in 2.1%. In the high TMB cohort, 93% of tumors harbored a driver mutation; 70% and 63% in the intermediate and low TMB cohorts, respectively (P < 0.05). However, when excluding tumor suppressor genes, high TMB tumors had a decreased incidence of driver mutations (P < 0.001). BRAF alterations were not identified in high TMB tumors, but were enriched in low TMB tumors (P < 0.01). Conversely, there was an association between high TMB tumors and TP53 mutations (P < 10^-13 ). Of the 15 tumors with high TMB, 14 were high-grade gliomas and 13 had alterations in TP53. Three homozygous mismatch repair deletions identified were associated with a higher TMB (P < 0.01).

CONCLUSIONS

Specific driver mutations appear to have a relationship with TMB. These represent populations in which ICPIs may be more or less effective.