Citations

This webinar is the first of a new series that brings together international experts to discuss ongoing developments in cancer research. This webinar focusses on emerging therapeutics, with speakers covering areas including immunotherapy, metabolic targets, and the treatment of lung and colorectal cancers. Our panellists discuss these developments, their ongoing challenges, and their global perspectives.

Abstract Introduction: Pediatric rhabdomyosarcoma (RMS) is the most common soft tissue tumor in children, with nearly 20% of children presenting with locally aggressive and/or metastatic disease. Despite aggressive chemotherapy and radiotherapy, the 5-year overall survival rate is still less than 40%. In addition, resistance to chemotherapy remains the major cause of cancer-related mortality. Therefore, there is an unmet need to develop more effective and tolerable therapeutic strategies for the treatment of RMS. Our overall objective is to leverage transcriptomic and proteomic profiling methods to identify RMS-specific surface proteins targetable with immune-based therapies. Methods: To identify therapeutic targets, we performed cell-surface capture and mass spectrometry on fusion-positive (FP), fusion-negative (FN) RMS and normal skeletal muscle. Transcriptomic datasets of RMS tumor specimens and normal tissue were employed to identify high-confidence RMS-specific cell-surface proteins. Expression of immune checkpoint molecules was confirmed by flow cytometry, western blot and PCR. Paraffin-embedded tissue sections were used to determine protein expression and prognostic value in RMS patients. We developed an in vitro T-cell killing assay to assess the functional role of immune checkpoint molecules on the antitumor immune response. Results: Surfaceome profiling of RMS cells revealed unique protein signatures specific for each tumor type and normal tissue. We have identified 5061 cell-surface proteins in RMS and 31.6% of proteins were correctly located at the plasma membrane. By integrating proteomic and transcriptomic data, we have identified 30 and 38 proteins significantly overexpressed in fusion-negative and fusion-positive RMS respectively compared to normal muscle. We have identified the immune checkpoint molecule B7-H3 as cell-surface protein overexpressed in both RMS subtypes. Strong expression of B7-H3 was also observed in patient’s tumor specimens. Genetic deletion of B7-H3 gene in RMS cells was associated with higher antitumor immune response in tumor cells co-cultured with CD8+-T cells. No difference was observed in tumor cell proliferation and radioresistance. Conclusions: Through integrated transcriptomic and proteomic profiling, we have discovered B7-H3 as a key regulator of tumor immune-evasion in RMS. B7-H3 is a suitable immunotherapy target for the treatment of RMS. Further studies are warranted to elucidate underlying mechanisms of B7-H3 function in RMS. Citation Format: Roxane R. Lavoie, Fabrice Lucien, Patricio C. Gargollo, Mohamed E. Ahmed, Yohan Kim, Emily Baer, Doris Phelps, Cristine M. Charlesworth, Benjamin J. Madden, Liguo Wang, Peter J. Hougthon, John Cheville, Haidong Dong, Candace F. Granberg. Surfaceome profiling of rhabdomyosarcoma reveals B7-H3 as a mediator of immune evasion [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr A036.

Diagnostic error or delay (DEOD) is common in the acute care setting and results in poor patient outcomes. Many factors contribute to DEOD, but little is known about how contributors may differ across acute care areas and professional roles. As part of a sequential exploratory mixed methods research study, we surveyed acute care clinical stakeholders about the frequency with which different factors contribute to DEOD. Survey respondents could also propose solutions in open text fields. N = 220 clinical stakeholders completed the survey. Care Team Interactions, Systems and Process, Patient, Provider, and Cognitive factors were perceived to contribute to DEOD with similar frequency. Organization and Infrastructure factors were perceived to contribute to DEOD significantly less often. Responses did not vary across acute care setting. Physicians perceived Cognitive factors to contribute to DEOD more frequently compared to those in other roles. Commonly proposed solutions included: technological solutions, organization level fixes, ensuring staff know and are encouraged to work to the full scope of their role, and cultivating a culture of collaboration and respect. Multiple factors contribute to DEOD with similar frequency across acute care areas, suggesting the need for a multi-pronged approach that can be applied across acute care areas.

AbstractVon Willebrand factor (VWF) level and/or function is altered in von Willebrand disease (VWD), the most common heritable bleeding disorder worldwide. Laboratory assessment of VWF is continually evolving. Historically, the primary method for the assessment of VWF platelet-binding activity was the ristocetin cofactor assay (VWF:RCo). Contemporary alternative measures of VWF platelet-binding activity include VWF:GPIbR (recombinant; using ristocetin), VWF:GPIbM (recombinant; gain-of-function mutant), and monoclonal antibody. Recently, the American Society of Hematology, International Society on Thrombosis and Haemostasis, National Hemophilia Foundation, and World Federation of Hemophilia collaboration issued guidelines recommending the use of newer assays of VWF platelet-binding activity (VWF: GPIbM, VWF: GPIbR) over VWF:RCo, given known limitations of the VWF:RCo assay. Despite this recommendation, the newer VWF:GPIbM and VWF:GPIbR assays are not United States Food and Drug Administration cleared, limiting their availability in the United States. We sought to assess assay utilization trends, agreement of VWF testing methods, and imprecision of VWF testing (based on assigned sample type) from the College of American Pathologists Proficiency Testing Surveys. The analysis confirms that, while VWF antigen testing has low imprecision, the various VWF activity assays have significant interassay variability, with VWF:RCo showing greater imprecision than the newer GPIb-binding assays. The overall trends in assay utilization reflect the barriers to complete compliance with modern VWD diagnostic guidelines in North America.

AbstractVon Willebrand factor (VWF) level and/or function is altered in von Willebrand disease (VWD), the most common heritable bleeding disorder worldwide. Laboratory assessment of VWF is continually evolving. Historically, the primary method for the assessment of VWF platelet-binding activity was the ristocetin cofactor assay (VWF:RCo). Contemporary alternative measures of VWF platelet-binding activity include VWF:GPIbR (recombinant; using ristocetin), VWF:GPIbM (recombinant; gain-of-function mutant), and monoclonal antibody. Recently, the American Society of Hematology, International Society on Thrombosis and Haemostasis, National Hemophilia Foundation, and World Federation of Hemophilia collaboration issued guidelines recommending the use of newer assays of VWF platelet-binding activity (VWF: GPIbM, VWF: GPIbR) over VWF:RCo, given known limitations of the VWF:RCo assay. Despite this recommendation, the newer VWF:GPIbM and VWF:GPIbR assays are not United States Food and Drug Administration cleared, limiting their availability in the United States. We sought to assess assay utilization trends, agreement of VWF testing methods, and imprecision of VWF testing (based on assigned sample type) from the College of American Pathologists Proficiency Testing Surveys. The analysis confirms that, while VWF antigen testing has low imprecision, the various VWF activity assays have significant interassay variability, with VWF:RCo showing greater imprecision than the newer GPIb-binding assays. The overall trends in assay utilization reflect the barriers to complete compliance with modern VWD diagnostic guidelines in North America.

Abstract Background and Aims: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a member of TNF superfamily, is predominantly expressed on immune cells. Engagement of TRAIL with its cognate receptor, TRAIL-R (TR), leads to cancer cells apoptosis. Although the anti-tumor role of TRAIL-TR has been extensively studied, TRAIL agonists have had very limited anti-cancer activity in human clinical trials. TRAIL signaling can facilitate the myeloid response. However, this potential immunosuppressive function of TRAIL has not been examined extensively in cancer biology. Cholangiocarcinoma (CCA), a highly lethal biliary tract cancer, has a dense immunosuppressive microenvironment. Accordingly, CCA provides a model to examine the potential immune regulatory function of TRAIL in cancer biology. Methods: Using syngeneic, orthotopic murine models of CCA, (PMID: 29464042), murine CCA cells (SB cells) that express both Trail and Trail receptor (Tr) were implanted into livers of WT Tr− / − and LyzcreTrf/f mice, the latter have a specific deletion of TRAIL-R on myeloid cells. Hence, in this model the host immune cells express Trail but not the receptor; therefore, they would be capable of inducing TRAIL-mediated apoptosis in CCA cells but would be resistant to TRAIL-mediated immunosuppression. After 4 weeks of tumor growth, mice were sacrificed, and tumors were characterized using flow cytometry. Results: We observed that Tr− / − mice had a significant reduction in tumor burden compared to WT mice. Myeloid-derived suppressor cells (MDSCs) were significantly decreased in Tr− / − tumors compared to WT tumors. Implantation of SB cells into LyzcreTrf/f mice resulted in a marked reduction in tumor burden and attenuation of MDSC infiltration compared to Lyzcre mice. In vitro functional studies employing MDSCs from mice deficient in Tr (MDSC-Tr −/−) were carried out. Compared to WT MDSCs, coculture of MDSC-Tr− /- with SB cells resulted in a significant reduction in the proliferation and immunosuppressive function of MDSCs. Moreover, following cocultured with SB cells, immunofluorescence analysis demonstrated that MDSC-Tr− / − had a reduction in the nuclear translocation of the NFkB subunit P65 compared to WT MDSCs. These data suggest that TRAIL-TR augments MDSC proliferation via NFkB. In conclusion, we have demonstrated that Tr− / − mice have a significant reduction in CCA tumor burden and MDSC infiltration. These results indicate that TRAIL-TR facilitates tumor immune escape and progression by fostering MDSC immunosuppressive function and infiltration, in an NFkB-dependent manner. Direct targeting of TRAIL on CCA cells is a potential anti-tumor strategy. Citation Format: Emilien Loeuillard, Jingchun Yang, Dong Haidong, Gregory Gores, Sumera Ilyas. Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL)-TRAIL-R Mediates Cholangiocarcinoma Tumor Immune Evasion by Enhancing Myeloid-Derived Suppressive Cell Population [abstract]. In: Proceedings of the AACR Special Conference: Advances in the Pathogenesis and Molecular Therapies of Liver Cancer; 2022 May 5-8; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(17_Suppl):Abstract nr PO032.

AbstractHeparin-induced thrombocytopenia (HIT) is suspected much more often than it is confirmed. Technically simple platelet factor 4 (PF4)-polyanion enzyme-linked immunosorbent assays (ELISAs) are sensitive but nonspecific. In contrast, accurate functional tests such as the serotonin release assay, heparin-induced platelet activation assay, and PF4-dependent P-selectin expression assay require fresh platelets and have complex assay end points, limiting their availability to specialized reference laboratories. To enable broad deployment of functional testing, we sought to extend platelet viability significantly by optimizing storage conditions and developed a simple functional assay end point by measuring the release of a platelet α-granule protein, thrombospondin-1 (TSP1), in an ELISA format. Platelet cryopreservation conditions were optimized by freezing platelets at controlled cooling rates that preserve activatability. Several-month-old cryopreserved platelets were treated with PF4 or heparin and were evaluated for their ability to be activated by HIT and vaccine-induced immune thrombotic thrombocytopenia (VITT) antibodies in the TSP1 release assay (TRA). HIT and spontaneous HIT patient samples induced significantly higher TSP1 release using both PF4-treated (PF4-TRA) and heparin-treated cryopreserved platelets relative to samples from patients suspected of HIT who lacked platelet-activating antibodies. This latter group included several patients that tested strongly positive in PF4-polyanion ELISA but were not platelet-activating. Four VITT patient samples tested in the TRA activated PF4-treated, but not heparin-treated, cryopreserved platelets, consistent with recent data suggesting the requirement for PF4-treated platelets for VITT antibody detection. These findings have the potential to transform the testing paradigm in HIT and VITT, making decentralized, technically simple functional testing available for rapid and accurate in-hospital diagnosis.

BackgroundCurative surgical treatments afford the best prognosis for patients with intrahepatic cholangiocarcinoma (iCCA); however, the comparative effectiveness of treatment options and factors associated with curative treatment receipt for early stage iCCA remain unknown.MethodsThe authors identified patients who were diagnosed with early stage iCCA, defined as a unifocal tumor <3 cm, during 2004–2018 from the National Cancer Database. Multivariable logistic and Cox regression analyses were used to identify the factors associated with curative treatment and overall survival (OS), respectively.ResultsThe proportion of patients with early stage iCCA increased from 4.5% in 2004 to 7.3% in 2018, with the odds of early stage detection increasing by 3.1% per year (odds ratio [OR], 1.031; 95% CI, 1.015–1.049). Of 1093 patients who had early stage iCCA, 464 (42.5%) underwent resection, 113 (10.3%) underwent ablation, 62 (5.7%) underwent liver transplantation, and 454 (41.5%) received noncurative treatments. Hispanic patients (adjusted OR [aOR], 0.57; 95% CI, 0.33–0.97) and Black patients (aOR, 0.47; 95% CI, 0.28–0.77) were less likely to receive curative treatments than White patients. Compared with patients who underwent surgical resection, those who underwent liver transplantation had a trend toward improved OS (adjusted hazard ratio [aHR], 0.63; 95% CI, 0.37–1.08), whereas those who underwent local ablation (aHR, 1.39; 95% CI, 1.01–1.92) and noncurative treatments (aHR, 3.97; 95% CI, 3.24–4.88) experienced worse OS.ConclusionsMore than one third of patients with early stage iCCA did not receive curative treatment, with Hispanic and Black patients being less likely to receive curative treatments than White patients. Surgical resection and liver transplantation were associated with improved survival compared with local ablation. Future studies should investigate disparities in curative treatment receipt and outcomes for early stage iCCA.

ABSTRACT Introduction: Neutrophil extracellular traps (NETs) trigger thrombin generation. We aimed to characterize the effects of deoxyribonuclease (DNAse) on NET components (cell-free DNA [cfDNA] and histones) and thrombin generation after trauma. Methods: Citrated plasma samples were collected from trauma patients and healthy volunteers. Thrombin generation (calibrated automated thrombogram) was measured as lag time (LT, in minutes), peak height (in nM), and time to peak thrombin generation (in minutes). Citrullinated histone 3 (CitH3) and 4 (CitH4) were measured by enzyme-linked immunosorbent assay; cfDNA by PicoGreen (all in nanograms per milliliter). Samples analyzed +/− DNAse (1,000 U/mL). Results expressed as median and quartiles [Q1, Q3], Wilcoxon testing, P < 0.05 significant. Results: We enrolled 46 patients (age, 48 [31, 67] years; 67% male) and 21 volunteers (age, 45 [28, 53] years; 43% male). Deoxyribonuclease treatment of trauma plasma led to shorter LT (3.11 [2.67, 3.52] min; 2.93 [2.67, 3.19] min), shorter time to peak thrombin generation (6.00 [5.30, 6.67] min; 5.48 [5.00, 6.00] min), greater peak height (273.7 [230.7, 300.5] nM; 288.7 [257.6, 319.2] nM), decreased cfDNA (576.9 [503.3, 803.1] ng/mL; 456.0 [393.5, 626.7] ng/mL), decreased CitH3 (4.54 [2.23, 10.01] ng/mL; 3.59 [1.93, 7.98] ng/mL), and increased H4 (1.30 [0.64, 6.36] ng/mL; 1.75 [0.83, 9.67] ng/mL), all P < 0.001. The effect of DNAse was greater on trauma patients as compared with volunteers for LT (ΔLT, −0.21 vs. −0.02 min, P = 0.007), cfDNA (ΔcfDNA −133.4 vs. −84.9 ng/mL, P < 0.001), and CitH3 (ΔCitH3, –0.65 vs. −0.11 ng/mL, P = 0.004). Conclusion: Deoxyribonuclease treatment accelerates thrombin generation kinetics in trauma patient samples as compared with healthy volunteers. These findings suggest that NETs may contribute to the hypercoagulable state observed in trauma patients.