Intratumoral T-cell receptor repertoire composition predicts overall survival in patients with pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy that is refractory to immune checkpoint inhibitor therapy. However, intratumoral T-cell infiltration correlates with improved overall survival (OS). Herein, we characterized the diversity and antigen specificity of the PDAC T-cell receptor (TCR) repertoire to identify novel immune-relevant biomarkers. Demographic, clinical, and TCR-beta sequencing data were collated from 353 patients across three cohorts that underwent surgical resection for PDAC. TCR diversity was calculated using Shannon Wiener index, Inverse Simpson index, and "True entropy." Patients were clustered by shared repertoire specificity. TCRs predictive of OS were identified and their associated transcriptional states were characterized by single-cell RNAseq. In multivariate Cox regression models controlling for relevant covariates, high intratumoral TCR diversity predicted OS across multiple cohorts. Conversely, in peripheral blood, high abundance of T-cells, but not high diversity, predicted OS. Clustering patients based on TCR specificity revealed a subset of TCRs that predicts OS. Interestingly, these TCR sequences were more likely to encode CD8+ effector memory and CD4+ T-regulatory (Tregs) T-cells, all with the capacity to recognize beta islet-derived autoantigens. As opposed to T-cell abundance, intratumoral TCR diversity was predictive of OS in multiple PDAC cohorts, and a subset of TCRs enriched in high-diversity patients independently correlated with OS. These findings emphasize the importance of evaluating peripheral and intratumoral TCR repertoires as distinct and relevant biomarkers in PDAC.

Reversing immunosuppression in the tumor microenvironment of fibrolamellar carcinoma via PD-1 and IL-10 blockade

Fibrolamellar carcinoma (FLC) is a rare liver tumor driven by the DNAJ-PKAc fusion protein that affects healthy young patients. Little is known about the immune response to FLC, limiting rational design of immunotherapy. Multiplex immunohistochemistry and gene expression profiling were performed to characterize the FLC tumor immune microenvironment and adjacent non-tumor liver (NTL). Flow cytometry and T cell receptor (TCR) sequencing were performed to determine the phenotype of tumor-infiltrating immune cells and the extent of T cell clonal expansion. Fresh human FLC tumor slice cultures (TSCs) were treated with antibodies blocking programmed cell death protein-1 (PD-1) and interleukin-10 (IL-10), with results measured by cleaved caspase-3 immunohistochemistry. Immune cells were concentrated in fibrous stromal bands, rather than in the carcinoma cell compartment. In FLC, T cells demonstrated decreased activation and regulatory T cells in FLC had more frequent expression of PD-1 and CTLA-4 than in NTL. Furthermore, T cells had relatively low levels of clonal expansion despite high TCR conservation across individuals. Combination PD-1 and IL-10 blockade signficantly increased cell death in human FLC TSCs. Immunosuppresion in the FLC tumor microenvironment is characterized by T cell exclusion and exhaustion, which may be reversible with combination immunotherapy.

Are enhanced recovery protocols after pancreatoduodenectomy still efficient when applied in elderly patients? A systematic review and individual patient data meta-analysis

BACKGROUND

This meta-analysis investigated the effects of enhanced recovery after surgery (ERAS) protocols compared to conventional care on postoperative outcomes in patients aged 70 years or older undergoing pancreatoduodenectomy (PD).

METHODS

Five databases were systematically searched. Comparative studies with available individual patient data (IPD) were included. The main outcomes were postoperative morbidity, length of stay, readmission and postoperative functional recovery elements. To assess an age-dependent effect, the group was divided in septuagenarians (70-79 years) and older patients (≥80 years).

RESULTS

IPD were obtained from 15 of 31 eligible studies comprising 1109 patients. The overall complication and major complication rates were comparable in both groups (OR 0.92 [95% CI: 0.65-1.29], p = .596 and OR 1.22 [95% CI: 0.61-2.46], p = .508). Length of hospital stay tended to be shorter in the ERAS group compared to the conventional care group (-0.14 days [95% CI: -0.29 to 0.01], p = .071) while readmission rates were comparable and the total length of stay including days in hospital after readmission tended to be shorter in the ERAS group (-0.28 days [95% CI: -0.62 to 0.05], p = .069). In the subgroups, the length of stay was shorter in octogenarians treated with ERAS (-0.36 days [95% CI: -0.71 to -0.004], p = .048). The readmission rate increased slightly but not significantly while the total length of stay was not longer in the ERAS group.

CONCLUSION

ERAS in the elderly is safe and its benefits are preserved in the care of even in patients older than 80 years. Standardized care protocol should be encouraged in all pancreatic centers.

Toll-Like Receptor 4 Agonist Injection With Concurrent Radiotherapy in Patients With Metastatic Soft Tissue Sarcoma: A Phase 1 Nonrandomized Controlled Trial

Importance

Metastatic soft tissue sarcomas (STSs) have limited systemic therapy options, and immunomodulation has not yet meaningfully improved outcomes. Intratumoral (IT) injection of the toll-like receptor 4 (TLR4) agonist glycopyranosyl lipid A in stable-emulsion formulation (GLA-SE) has been studied as immunotherapy in other contexts.

Objective

To evaluate the safety, efficacy, and immunomodulatory effects of IT GLA-SE with concurrent radiotherapy in patients with metastatic STS with injectable lesions.

Design, Setting, and Participants

This phase 1 nonrandomized controlled trial of patients with STS was performed at a single academic sarcoma specialty center from November 17, 2014, to March 16, 2016. Data analysis was performed from August 2016 to September 2022.

Interventions

Two doses of IT GLA-SE (5 μg and 10 μg for 8 weekly doses) were tested for safety in combination with concurrent radiotherapy of the injected lesion.

Main Outcomes and Measures

Primary end points were safety and tolerability. Secondary and exploratory end points included local response rates as well as measurement of antitumor immunity with immunohistochemistry and T-cell receptor (TCR) sequencing of tumor-infiltrating and circulating lymphocytes.

Results

Twelve patients (median [range] age, 65 [34-78] years; 8 [67%] female) were treated across the 2 dose cohorts. Intratumoral GLA-SE was well tolerated, with only 1 patient (8%) experiencing a grade 2 adverse event. All patients achieved local control of the injected lesion after 8 doses, with 1 patient having complete regression (mean regression, -25%; range, -100% to 4%). In patients with durable local response, there were detectable increases in tumor-infiltrating lymphocytes. In 1 patient (target lesion -39% at 259 days of follow-up), TCR sequencing revealed expansion of preexisting and de novo clonotypes, with convergence of numerous rearrangements coding for the same binding sequence (suggestive of clonal convergence to antitumor targets). Single-cell sequencing identified these same expanded TCR clones in peripheral blood after treatment; these T cells had markedly enhanced Tbet expression, suggesting TH1 phenotype.

Conclusions and Relevance

In this nonrandomized controlled trial, IT GLA-SE with concurrent radiotherapy was well tolerated and provided more durable local control than radiotherapy alone. Patients with durable local response demonstrated enhanced IT T-cell clonal expansion, with matched expansion of these clonotypes in the circulation. Additional studies evaluating synergism of IT GLA-SE and radiotherapy with systemic immune modulation are warranted.

Trial Registration

ClinicalTrials.gov Identifier: NCT02180698.

Production of an interleukin-10 blocking antibody by genetically engineered macrophages increases cancer cell death in human gastrointestinal tumor slice cultures

Although it can promote effector T-cell function, the summative effect of interleukin-10 (IL-10) in the tumor microenvironment (TME) appears to be suppressive; therefore, blocking this critical regulatory cytokine has therapeutic potential to enhance antitumor immune function. As macrophages efficiently localize to the TME, we hypothesized that they could be used as a delivery vehicle for drugs designed to block this pathway. To test our hypothesis, we created and evaluated genetically engineered macrophages (GEMs) that produce an IL-10-blocking antibody (αIL-10). Healthy donor human peripheral blood mononuclear cells were differentiated and transduced with a novel lentivirus (LV) encoding BT-063, a humanized αIL-10 antibody. The efficacy of αIL-10 GEMs was assessed in human gastrointestinal tumor slice culture models developed from resected specimens of pancreatic ductal adenocarcinoma primary tumors and colorectal cancer liver metastases. LV transduction led to sustained production of BT-063 by αIL-10 GEMs for at least 21 days. Transduction did not alter GEM phenotype as evaluated by flow cytometry, but αIL-10 GEMs produced measurable quantities of BT-063 in the TME that was associated with an ~5-fold higher rate of tumor cell apoptosis than control.

Leiomyosarcoma of the inferior vena cava: An uncommon malignancy requiring unique reconstructive approaches

Surgery is considered for patients without metastatic disease and with resectable primary tumor. Pre-operatively, high quality imaging is reviewed to determine the likely extent of resection, specifically including the need for potential en-bloc resection of adjacent organs. In cases where up-front surgical approach would expose the patient to excessive morbidity (such as bilateral nephrectomy, multi-visceral resection, or prohibitively high risk of positive margins), neoadjuvant chemotherapy and/or chemoradiotherapy is considered. Though data are sparse in LMS, a neoadjuvant regimen of doxorubicin and dacarbazine is typically considered for borderline resectable tumors at our institution; patients may be treated for up to 4 months with interval imaging every 2 months to evaluate for tumor response. Postoperatively, adjuvant systemic therapy or radiation may be considered for patients with positive surgical margins or high-grade tumors.

Emerging interleukin targets in the tumour microenvironment: implications for the treatment of gastrointestinal tumours

The effectiveness of antitumour immunity is dependent on intricate cytokine networks. Interleukins (ILs) are important mediators of complex interactions within the tumour microenvironment, including regulation of tumour-infiltrating lymphocyte proliferation, differentiation, migration and activation. Our evolving and increasingly nuanced understanding of the cell type-specific and heterogeneous effects of IL signalling has presented unique opportunities to fine-tune elaborate IL networks and engineer new targeted immunotherapeutics. In this review, we provide a primer for clinicians on the challenges and potential of IL-based treatment. We specifically detail the roles of IL-2, IL-10, IL-12 and IL-15 in shaping the tumour-immune landscape of gastrointestinal malignancies, paying particular attention to promising preclinical findings, early-stage clinical research and innovative therapeutic approaches that may properly place ILs to the forefront of immunotherapy regimens.

Perioperative Chemotherapy and Chemoradiotherapy for Patients With Resectable and Borderline Resectable Pancreatic Adenocarcinoma

OBJECTIVES

Pancreatic ductal adenocarcinoma (PDA) is the third most common cause of cancer death in the United States. Most patients who undergo resection develop recurrence. Standard treatment confers a median overall survival (OS) of 24 months. Exposure to alternate regimens may prevent chemoresistance. This study evaluated multiagent perioperative therapy for potentially resectable PDA patients to improve OS.

METHODS

A single center, phase 2, trial of patients with resectable or borderline resectable PDA. Patients received neoadjuvant therapy with induction chemotherapy (gemcitabine, docetaxel, capecitabine) for 3 cycles, chemoradiation (intensity-modulated radiation therapy with capecitabine and oxaliplatin) followed by surgery, and 2 months of adjuvant gemcitabine and oxaliplatin and 2 months of gemcitabine. The primary endpoint was OS. The secondary endpoint was recurrence-free survival (RFS).

RESULTS

Thirty-two eligible patients were enrolled. Twenty-two patients underwent surgical resection. After a median follow-up of 56.8 months, mOS was 31.6 months (95% confidence interval [CI], 14.2-58.1) for all patients, 58.1 months (95% CI, 31.6 to NR) for those who completed surgery. The mRFS was 31.3 months (95% CI, 12.5 to NR).

CONCLUSIONS

Perioperative therapy with GTX, chemoradiotherapy, and adjuvant GemOx/Gem resulted in promising survival of 58 months for patients who underwent resection and may represent another treatment option for PDA.

Blockade of interleukin 10 potentiates antitumour immune function in human colorectal cancer liver metastases

OBJECTIVE

Programmed cell death protein 1 (PD-1) checkpoint inhibition and adoptive cellular therapy have had limited success in patients with microsatellite stable colorectal cancer liver metastases (CRLM). We sought to evaluate the effect of interleukin 10 (IL-10) blockade on endogenous T cell and chimeric antigen receptor T (CAR-T) cell antitumour function in CRLM slice cultures.

DESIGN

We created organotypic slice cultures from human CRLM (n=38 patients' tumours) and tested the antitumour effects of a neutralising antibody against IL-10 (αIL-10) both alone as treatment and in combination with exogenously administered carcinoembryonic antigen (CEA)-specific CAR-T cells. We evaluated slice cultures with single and multiplex immunohistochemistry, in situ hybridisation, single-cell RNA sequencing, reverse-phase protein arrays and time-lapse fluorescent microscopy.

RESULTS

αIL-10 generated a 1.8-fold increase in T cell-mediated carcinoma cell death in human CRLM slice cultures. αIL-10 significantly increased proportions of CD8⁺ T cells without exhaustion transcription changes, and increased human leukocyte antigen - DR isotype (HLA-DR) expression of macrophages. The antitumour effects of αIL-10 were reversed by major histocompatibility complex class I or II (MHC-I or MHC-II) blockade, confirming the essential role of antigen presenting cells. Interrupting IL-10 signalling also rescued murine CAR-T cell proliferation and cytotoxicity from myeloid cell-mediated immunosuppression. In human CRLM slices, αIL-10 increased CEA-specific CAR-T cell activation and CAR-T cell-mediated cytotoxicity, with nearly 70% carcinoma cell apoptosis across multiple human tumours. Pretreatment with an IL-10 receptor blocking antibody also potentiated CAR-T function.

CONCLUSION

Neutralising the effects of IL-10 in human CRLM has therapeutic potential as a stand-alone treatment and to augment the function of adoptively transferred CAR-T cells.

KRAS Mutation Variants and Co-occurring PI3K Pathway Alterations Impact Survival for Patients with Pancreatic Ductal Adenocarcinomas

BACKGROUND

KRAS variant alleles may have differential biological properties which impact prognosis and therapeutic options in pancreatic ductal adenocarcinomas (PDA).

MATERIALS AND METHODS

We retrospectively identified patients with advanced PDA who received first-line therapy and underwent blood and/or tumor genomic sequencing at the University of Washington between 2013 and 2020. We examined the incidence of KRAS mutation variants with and without co-occurring PI3K or other genomic alterations and evaluated the association of these mutations with clinicopathological characteristics and survival using a Cox proportional hazards model.

RESULTS

One hundred twenty-six patients had genomic sequencing data; KRAS mutations were identified in 111 PDA and included the following variants: G12D (43)/G12V (35)/G12R (23)/other (10). PI3K pathway mutations (26% vs. 8%) and homologous recombination DNA repair (HRR) defects (35% vs. 12.5%) were more common among KRAS G12R vs. non-G12R mutated cancers. Patients with KRAS G12R vs. non-G12R cancers had significantly longer overall survival (OS) (HR 0.55) and progression-free survival (PFS) (HR 0.58), adjusted for HRR pathway co-mutations among other covariates. Within the KRAS G12R group, co-occurring PI3K pathway mutations were associated with numerically shorter OS (HR 1.58), while no effect was observed on PFS.

CONCLUSIONS

Patients with PDA harboring KRAS G12R vs. non-G12R mutations have longer survival, but this advantage was offset by co-occurring PI3K alterations. The KRAS/PI3K genomic profile could inform therapeutic vulnerabilities in patients with PDA.

A phase II trial of lanreotide for the prevention of postoperative pancreatic fistula

BACKGROUND

Clinically relevant postoperative pancreatic fistula (CR-POPF) is a significant contributor to morbidity after pancreatectomy. Somatostatin analogues have shown variable efficacy in the prevention of CR-POPF. Lanreotide is a somatostatin analogue ideally suited for perioperative use due to its long half-life and favorable side effect profile.

METHODS

We conducted a phase II single-arm trial of a single dose of preoperative lanreotide (120 mg) in patients undergoing either pancreaticoduodenectomy (PD) or distal pancreatectomy (DP). The primary outcome was development of CR-POPF or intra-abdominal abscess. Secondary outcomes included biochemical leak and overall morbidity.

RESULTS

A total of 98 patients completed the study. Sixty-two underwent PD (63.3%) and 36 underwent DP (36.7%). The primary outcome was observed in eight (8%) patients in the overall cohort, one from the DP group and seven from the PD group. Biochemical leak was detected in 12 (12.2%) patients in the overall cohort. Twenty-seven (27.5%) patients developed complications, of which 14 (14.2%) were major complications. Drug-related adverse events were limited to mild skin reactions in two (2%) patients.

CONCLUSION

Patients who received preoperative lanreotide developed CR-POPF at rates significantly lower than historical controls or published literature. This provides strong justification for a randomized controlled trial.

Combination immunotherapy for pancreatic cancer: challenges and future considerations

INTRODUCTION

: Immune checkpoint inhibitors (ICI) have not yielded significant efficacy in pancreatic ductal adenocarcinoma (PDA), despite the role of the innate and adaptive immune systems on progression and survival. However, recently identified pathways have identified new targets and generated promising clinical investigations into promoting an effective immune-mediated antitumor response in PDA.

AREAS COVERED

: We review biological mechanisms associated with immunotherapy resistance and outline strategies for therapeutic combinations with established and novel therapies in PDA.

EXPERT OPINION

: Pancreatic cancers rarely benefits from treatment with ICI due to an immunosuppressive tumor microenvironment (TME). New understandings of factors associated with the suppressive TME, include low and poor quality neoantigens, constrained effector T cells infiltration, and the presence of a dense, suppressive myeloid cell population. These findings have been translated into new clinical investigations evaluating novel therapies in combination with ICI and/or standard systemic chemotherapy and radiotherapy. The epithelial, immune, and stromal compartments are intricately related in PDA, and the framework for successful targeting of this disease requires a comprehensive and personalized approach.

A novel rat model for the study of postoperative pancreatic fistula

While over the past several decades mortality after pancreatic surgery has decreased to <5%, postoperative morbidity remains remarkably high, ranging from 15% to 65%. The development of a postoperative pancreatic fistula (POPF) is a significant contributor to morbidity in patients undergoing pancreatic surgery. POPF can lead to life-threatening conditions such as intra-abdominal abscess, uncontrolled hemorrhage, sepsis, and death. Rates of POPF have not significantly changed over time, despite the introduction of multiple technical and pharmacologic interventions aimed at their treatment and prevention. Unfortunately, there are few POPF experimental models that have been described in the literature and existing models are unable to reliably reproduce the clinical sequelae of POPF, limiting the development of new methods to prevent and treat POPF. Herein, we describe a new rat experimental model that reliably creates a POPF via transection of the common pancreatic duct.

Hypoxia-inducible lentiviral gene expression in engineered human macrophages

Background

Human immune cells, including monocyte-derived macrophages, can be engineered to deliver proinflammatory cytokines, bispecific antibodies, and chimeric antigen receptors to support immune responses in different disease settings. When gene expression is regulated by constitutively active promoters, lentiviral payload gene expression is unregulated, and can result in potentially toxic quantities of proteins. Regulated delivery of lentivirally encoded proteins may allow localized or conditional therapeutic protein expression to support safe delivery of adoptively transferred, genetically modified cells with reduced capacity for systemic toxicities.

Methods

In this study, we engineered human macrophages to express genes regulated by hypoxia responsive elements included in the lentiviral promoter region to drive conditional lentiviral gene expression only under hypoxic conditions. We tested transduced macrophages cultured in hypoxic conditions for the transient induced expression of reporter genes and the secreted cytokine, interleukin-12. Expression of hypoxia-regulated genes was investigated both transcriptionally and translationally, and in the presence of human tumor cells in a slice culture system. Finally, hypoxia-regulated gene expression was evaluated in a subcutaneous humanized-mouse cancer model.

Results

Engineered macrophages were shown to conditionally and tranisently express lentivirally encoded gene protein products, including IL-12 in hypoxic conditions in vitro. On return to normoxic conditions, lentiviral payload expression returned to basal levels. Reporter genes under the control of hypoxia response elements were upregulated under hypoxic conditions in the presence of human colorectal carcinoma cells and in the hypoxic xenograft model of glioblastoma, suggesting utility for systemic engineered cell delivery capable of localized gene delivery in cancer.

Conclusions

Macrophages engineered to express hypoxia-regulated payloads have the potential to be administered systemically and conditionally express proteins in tissues with hypoxic conditions. In contrast to immune cells that function or survive poorly in hypoxic conditions, macrophages maintain a proinflammatory phenotype that may support continued gene and protein expression when regulated by conditional hypoxia responsive elements and naturally traffic to hypoxic microenvironments, making them ideal vehicles for therapeutic payloads to hypoxic tissues, such as solid tumors. With the ability to fine-tune delivery of potent proteins in response to endogenous microenvironments, macrophage-based cellular therapies may therefore be designed for different disease settings.

Neoantigen-specific CD4+ T cells in human melanoma have diverse differentiation states and correlate with CD8+ T cell, macrophage, and B cell function

CD4⁺ T cells that recognize tumor antigens are required for immune checkpoint inhibitor efficacy in murine models, but their contributions in human cancer are unclear. We used single-cell RNA sequencing and T cell receptor sequences to identify signatures and functional correlates of tumor-specific CD4⁺ T cells infiltrating human melanoma. Conventional CD4⁺ T cells that recognize tumor neoantigens express CXCL13 and are subdivided into clusters expressing memory and T follicular helper markers, and those expressing cytolytic markers, inhibitory receptors, and IFN-γ. The frequency of CXCL13⁺ CD4⁺ T cells in the tumor correlated with the transcriptional states of CD8⁺ T cells and macrophages, maturation of B cells, and patient survival. Similar correlations were observed in a breast cancer cohort. These results identify phenotypes and functional correlates of tumor-specific CD4⁺ T cells in melanoma and suggest the possibility of using such cells to modify the tumor microenvironment.

Impact of enhanced recovery protocols after pancreatoduodenectomy: meta-analysis

BACKGROUND

This individual-patient data meta-analysis investigated the effects of enhanced recovery after surgery (ERAS) protocols compared with conventional care on postoperative outcomes in patients undergoing pancreatoduodenectomy.

METHODS

The Cochrane Library, MEDLINE, Embase, Scopus, and Web of Science were searched systematically for articles reporting outcomes of ERAS after pancreatoduodenectomy published up to August 2020. Comparative studies were included. Main outcomes were postoperative functional recovery elements, postoperative morbidity, duration of hospital stay, and readmission.

RESULTS

Individual-patient data were obtained from 17 of 31 eligible studies comprising 3108 patients. Time to liquid (mean difference (MD) -3.23 (95 per cent c.i. -4.62 to -1.85) days; P < 0.001) and solid (-3.84 (-5.09 to -2.60) days; P < 0.001) intake, time to passage of first stool (MD -1.38 (-1.82 to -0.94) days; P < 0.001) and time to removal of the nasogastric tube (3.03 (-4.87 to -1.18) days; P = 0.001) were reduced with ERAS. ERAS was associated with lower overall morbidity (risk difference (RD) -0.04, 95 per cent c.i. -0.08 to -0.01; P = 0.015), less delayed gastric emptying (RD -0.11, -0.22 to -0.01; P = 0.039) and a shorter duration of hospital stay (MD -2.33 (-2.98 to -1.69) days; P < 0.001) without a higher readmission rate.

CONCLUSION

ERAS improved postoperative outcome after pancreatoduodenectomy. Implementation should be encouraged.

Key chemokines direct migration of immune cells in solid tumors

Immune cell infiltration into solid tumors, their movement within the tumor microenvironment (TME), and interaction with other immune cells are controlled by their directed migration towards gradients of chemokines. Dysregulated chemokine signaling in TME favors the growth of tumors, exclusion of effector immune cells, and abundance of immunosuppressive cells. Key chemokines directing the migration of immune cells into tumor tissue have been identified. In this review, we discuss well-studied chemokine receptors that regulate migration of effector and immunosuppressive immune cells in the context of cancer immunology. We discuss preclinical models that have described the role of respective chemokine receptors in immune cell migration into TME and review preclinical and clinical studies that target chemokine signaling as standalone or combination therapies.

Neuroendocrine and Adrenal Tumors, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Neuroendocrine and Adrenal Gland Tumors focus on the diagnosis, treatment, and management of patients with neuroendocrine tumors (NETs), adrenal tumors, pheochromocytomas, paragangliomas, and multiple endocrine neoplasia. NETs are generally subclassified by site of origin, stage, and histologic characteristics. Appropriate diagnosis and treatment of NETs often involves collaboration between specialists in multiple disciplines, using specific biochemical, radiologic, and surgical methods. Specialists include pathologists, endocrinologists, radiologists (including nuclear medicine specialists), and medical, radiation, and surgical oncologists. These guidelines discuss the diagnosis and management of both sporadic and hereditary neuroendocrine and adrenal tumors and are intended to assist with clinical decision-making. This article is focused on the 2021 NCCN Guidelines principles of genetic risk assessment and counseling and recommendations for well-differentiated grade 3 NETs, poorly differentiated neuroendocrine carcinomas, adrenal tumors, pheochromocytomas, and paragangliomas.

Abstract 607: IL-15 is the most potent of tested gamma chain cytokines at inducing in situ proliferation of T cells in human pancreatic cancer

Background: Multiple factors, including dense stroma and high infiltration of suppressive immune cells make pancreatic ductal adenocarcinoma (PDA) challenging to treat with immunotherapy. The presence of intra-tumoral T cells positively correlates with improved survival for PDA patients. Gamma chain cytokines (GCCs) can augment T cell mediated anti-tumor immunity and various GCC agonist drugs have been applied in clinical trials for cancer. Besides evaluating the effect of GCC derived agonists using recovered blood or biopsies of treated patients, it is challenging to mechanistically study the effect of GCCs on tumor-resident immune cells in human samples.

Methods: Here we apply organotypic slice culture of surgically resected tumor tissues to study the effect of GCCs on intra-tumoral immune cells. We treated slices of PDAs with GCCs (IL-2, IL-7, IL-15 and IL-21) for 6 days. Immune cells, especially T cells emigrated from the tumor slices into the culture supernatant. On day 6 we fixed intact tumor slices for multiplex immunohistochemistry (mIHC) and analyzed emigrated cells using flow cytometry.

Results: IL-15 and IL-7 potently induced T cell proliferation. The effect of IL-7 and IL-15 on T cell proliferation was higher for T cells that expressed markers of antigen experience such as CD39 and PD1 (Table 1). While IL-15 had the strongest effect on tumor-derived T cells, IL-15 and IL-7 were similar in their effect on T cells in the blood of the same patient, suggesting that IL-15 is especially effective in inducing the proliferation of tumor-infiltrating T cells. The effect of IL-15 on enhanced T cell proliferation was also seen within tumor slices, as revealed by mIHC.

Conclusion: Our data suggest that IL-15 is the most potent GCC at inducing in situ expansion of tumor-resident T cells, including T cells that show signs of antigen experience.

Table 1.IL-15 induces in situ T cell proliferation in PDA.AssayGroupsUntreatedIL-2IL-7IL-15IL-21ParameterFlow Cytometry%Ki67+CD8+cells of live cells0.090.040.360.595.001.3514.331.200.310.14%CD39+CD103+of CD8+0.130.150.110.040.290.140.620.180.130.08%PD1+of CD8+25.107.2223.233.1030.484.7446.483.5037.402.32mIHC%CD8+Ki67+ of all cells0.16 0.04(n=2)0.83 (n=1)0.550.38(n=2)2.200.04(n=2)0.490.41(n=2)n=4 slices for each group for flow cytometry. Data are from one experiment*. MeanSD is shown. Two doses (10-fold difference) for each cytokine were tested and results only for the low dose are shown.*Another experiment with groups IL-2 and IL-2+IL-15 was performed and had similar results for the effect of IL-15

Citation Format: Karan Kohli, Shihong Zhang, Xiuyun Jiang, Cynthia Hsu, Arezou Abbasi, Teresa S. Kim, Venu G. Pillarisetty. IL-15 is the most potent of tested gamma chain cytokines at inducing in situ proliferation of T cells in human pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 607.

Protocol for tissue slice cultures from human solid tumors to study therapeutic response

The impact of systemic therapy on the tumor microenvironment has been difficult to study in human solid tumors. Our protocol describes steps for establishing slice cultures to investigate response to chemotherapies, immunotherapies, or adoptive cell therapies. Endpoints include changes in viability, histology, live-cell imaging, and multi-omics analyses. The protocol has been applied to a broad array of gastrointestinal malignancies. Culture conditions and treatment parameters can be modified for specific experiments. The platform is highly flexible and easy to manipulate.

For complete details on the use and execution of this protocol, please refer to Kenerson et al. (2020), Jabbari et al. (2020), Brempelis et al. (2020), and Jiang et al. (2017).

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Organotypic tumor slice cultures (TSCs) can be utilized to study human cancer

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TSCs provide a model to study effects of chemo-, immuno-, and cell-based therapies

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Tumor response to treatment can be assessed using multiple readouts

IL-15 mediated expansion of rare durable memory T cells following adoptive cellular therapy

Background

Synovial sarcoma (SS) and myxoid/round cell liposarcoma (MRCL) are ideal solid tumors for the development of adoptive cellular therapy (ACT) targeting NY-ESO-1, as a high frequency of tumors homogeneously express this cancer-testes antigen. Data from early phase clinical trials have shown antitumor activity after the adoptive transfer of NY-ESO-1–specific T cells. In these studies, persistence of NY-ESO-1 specific T cells is highly correlated with response to ACT, but patients often continue to have detectable transferred cells in their peripheral blood following progression.

Method

We performed a phase I clinical trial evaluating the safety of NY-ESO-1–specific endogenous T cells (ETC) following cyclophosphamide conditioning. Peripheral blood mononuclear cells (PBMCs) from treated patients were evaluated by flow cytometry and gene expression analysis as well as through ex vivo culture assays with and without IL-15.

Results

Four patients were treated in a cohort using ETC targeting NY-ESO-1 following cyclophosphamide conditioning. Treatment was well tolerated without significant toxicity, but all patients ultimately had disease progression. In two of four patients, we obtained post-treatment tumor tissue and in both, NY-ESO-1 antigen was retained despite clear detectable persisting NY-ESO-1–specific T cells in the peripheral blood. Despite a memory phenotype, these persisting cells lacked markers of proliferation or activation. However, in ex vivo culture assays, they could be induced to proliferate and kill tumor using IL-15. These results were also seen in PBMCs from two patients who received gene-engineered T-cell receptor–based products at other centers.

Conclusions

ETC targeting NY-ESO-1 with single-agent cyclophosphamide alone conditioning was well tolerated in patients with SS and those with MRCL. IL-15 can induce proliferation and activity in persisting NY-ESO-1–specific T cells even in patients with disease progression following ACT. These results support future work evaluating whether IL-15 could be incorporated into ACT trials post-infusion or at the time of progression.

Analysis of Differentiation Changes and Outcomes at Time of First Recurrence of Retroperitoneal Liposarcoma by Transatlantic Australasian Retroperitoneal Sarcoma Working Group (TARPSWG)

BACKGROUND

Local recurrence following resection of retroperitoneal liposarcoma (RLPS) is common. Well-differentiated (WD) and dedifferentiated (DD) RLPS are distinct entities with differing outcomes. A few reports suggest that WDLPS can recur as DDLPS and that DDLPS can recur as WDLPS. This study evaluates whether this change in differentiation from the primary tumor to the first local recurrence impacts long-term outcomes.

METHODS

Retrospective review from 22 sarcoma centers identified consecutive patients who underwent resection for a first locally recurrent RLPS from January 2002 to December 2011. Outcomes measured included overall survival, local recurrence, and distant metastasis.

RESULTS

A total of 421 RPLS patients were identified. Of the 230 patients with primary DDLPS, 34 (15%) presented WDLPS upon recurrence (DD → WD); and of the 191 patients with primary WDLPS, 54 (28%) presented DDLPS upon recurrence (WD → DD). The 6-year overall survival probabilities (95% CI) for DD → DD, DD → WD, WD → WD, and WD → DD were 40% (32-48%), 73% (58-92%), 76% (68-85%), and 56% (43-73%) (p < 0.001), respectively. The 6-year second local recurrence incidence was 66% (59-73%), 63% (48-82%), 66% (57-76%), and 77% (66-90%), respectively. The 6-year distant metastasis incidence was 13% (9-19%), 3% (0.4-22%), 5% (2-11%), and 4% (1-16%), respectively. On multivariable analysis, DD → WD was associated with improved overall survival when compared with DD → DD (p < 0.001). Moreover, WD → DD was associated with a higher risk of LR (p = 0.025) CONCLUSION: A change in RLPS differentiation from primary tumor to first local recurrence appears to impact survival. These findings may be useful in counseling patients on their prognosis and subsequent management.

IWATE criteria are associated with perioperative outcomes in robotic hepatectomy: a retrospective review of 225 resections

Background

Robotic hepatectomy (RH) is increasingly utilized for minor and major liver resections. The IWATE criteria were developed to classify minimally invasive liver resections by difficulty. The objective of this study was to apply the IWATE criteria in RH and to describe perioperative and oncologic outcomes of RH over the last decade at our institution.

Methods

Perioperative and oncologic outcomes of patients who underwent RH between 2011 and 2019 were retrospectively collected. The difficulty level of each operation was assessed using the IWATE criteria, and outcomes were compared at each level. Univariate linear regression was performed to characterize the relationship between IWATE criteria and perioperative outcomes (OR time, EBL, and LOS), and a multivariable model was also developed to address potential confounding by patient characteristics (age, sex, BMI, prior abdominal surgery, ASA class, and simultaneous non-hepatectomy operation).

Results

Two hundred and twenty-five RH were performed. Median IWATE criteria for RH were 6 (IQR 5–9), with low, intermediate, advanced, and expert resections accounting for 23% (n = 51), 34% (n = 77), 32% (n = 72), and 11% (n = 25) of resections, respectively. The majority of resections were parenchymal-sparing approaches, including anatomic segmentectomies and non-anatomic partial resections. 30-day complication rate was 14%, conversion to open surgery occurred in 9 patients (4%), and there were no deaths within 30 days postoperatively. In the univariate linear regression analysis, IWATE criteria were positively associated with OR time, EBL, and LOS. In the multivariable model, IWATE criteria were independently associated with greater OR time, EBL, and LOS. Two-year overall survival for hepatocellular carcinoma and intrahepatic cholangiocarcinoma was 94% and 50%, respectively.

Conclusion

In conclusion, the IWATE criteria are associated with surgical outcomes after RH. This series highlights the utility of RH for difficult hepatic resections, particularly parenchymal-sparing resections in the posterosuperior sector, extending the indication of minimally invasive hepatectomy in experienced hands and potentially offering select patients an alternative to open hepatectomy or other less definitive liver-directed treatment options.

Postoperative Morbidity After Resection of Recurrent Retroperitoneal Sarcoma: A Report from the Transatlantic Australasian RPS Working Group (TARPSWG)

BACKGROUND

This study aimed to evaluate perioperative morbidity after surgery for first locally recurrent (LR1) retroperitoneal sarcoma (RPS). Data concerning the safety of resecting recurrent RPS are lacking.

METHODS

Data were collected on all patients undergoing resection of RPS-LR1 at 22 Trans-Atlantic Australasian Retroperitoneal Sarcoma Working Group (TARPSWG) centers from 2002 to 2011. Uni- and multivariable logistic models were fitted to study the association between major (Clavien-Dindo grade ≥ 3) complications and patient/surgery characteristics as well as outcome. The resected organ score, a method of standardizing the number of organs resected, as previously described by the TARPSWG, was used.

RESULTS

The 681 patients in this study had a median age of 59 years, and 51.8% were female. The most common histologic subtype was de-differentiated liposarcoma (43%), the median resected organ score was 1, and 83.3% of the patients achieved an R0 or R1 resection. Major complications occurred for 16% of the patients, and the 90-day mortality rate was 0.4%. In the multivariable analysis, a transfusion requirement was found to be a significant predictor of major complications (p < 0.001) and worse overall survival (OS) (p = 0.010). However, having a major complication was not associated with a worse OS or a higher incidence of local recurrence or distant metastasis.

CONCLUSIONS

A surgical approach to recurrent RPS is relatively safe and comparable with primary RPS in terms of complications and postoperative mortality when performed at specialized sarcoma centers. Because alternative effective therapies still are lacking, when indicated, resection of a recurrent RPS is a reasonable option. Every effort should be made to minimize the need for blood transfusions.

Modulation of Immune Checkpoints by Chemotherapy in Human Colorectal Liver Metastases

Metastatic colorectal cancer (CRC) is a major cause of cancer-related death, and incidence is rising in younger populations (younger than 50 years). Current chemotherapies can achieve response rates above 50%, but immunotherapies have limited value for patients with microsatellite-stable (MSS) cancers. The present study investigates the impact of chemotherapy on the tumor immune microenvironment. We treat human liver metastases slices with 5-fluorouracil (5-FU) plus either irinotecan or oxaliplatin, then perform single-cell transcriptome analyses. Results from eight cases reveal two cellular subtypes with divergent responses to chemotherapy. Susceptible tumors are characterized by a stemness signature, an activated interferon pathway, and suppression of PD-1 ligands in response to 5-FU+irinotecan. Conversely, immune checkpoint TIM-3 ligands are maintained or upregulated by chemotherapy in CRC with an enterocyte-like signature, and combining chemotherapy with TIM-3 blockade leads to synergistic tumor killing. Our analyses highlight chemomodulation of the immune microenvironment and provide a framework for combined chemo-immunotherapies.

CRLM slice culture can assess immune response to chemotherapy

Single-cell analysis identifies cancer subtypes with differing response to chemotherapy

5-FU+irinotecan modulates interferon and PD-L1 pathways in stem-like CRLM

Combining chemotherapy with TIM-3 blockade is synergistic in enterocyte-like CRLM

Pancreatic paraganglioma mimicking pancreatic neuroendocrine tumor

Extra-adrenal paragangliomas are rare tumors arising from the chromaffin cells of the autonomic nervous system. Retroperitoneal paragangliomas may present as a pancreatic mass. We present a case of a 61-year-old woman with an incidentally found pancreatic mass (7.2 × 6.5 cm) in the CT scan. EUS- guided FNA result was compatible with pancreatic neuroendocrine tumor. Patient underwent pancreaticoduodenectomy and histopathologic assessment revealed the mass was an extra-adrenal paraganglioma. Preoperative diagnosis of pancreatic paragangliomas can be challenging due to imaging and histopathologic similarities with pancreatic neuroendocrine tumors.

Genetically engineered macrophages persist in solid tumors and locally deliver therapeutic proteins to activate immune responses

Background

Though currently approved immunotherapies, including chimeric antigen receptor T cells and checkpoint blockade antibodies, have been successfully used to treat hematological and some solid tumor cancers, many solid tumors remain resistant to these modes of treatment. In solid tumors, the development of effective antitumor immune responses is hampered by restricted immune cell infiltration and an immunosuppressive tumor microenvironment (TME). An immunotherapy that infiltrates and persists in the solid TME, while providing local, stable levels of therapeutic to activate or reinvigorate antitumor immunity could overcome these challenges faced by current immunotherapies.

Methods

Using lentivirus-driven engineering, we programmed human and murine macrophages to express therapeutic payloads, including Interleukin (IL)-12. In vitro coculture studies were used to evaluate the effect of genetically engineered macrophages (GEMs) secreting IL-12 on T cells and on the GEMs themselves. The effects of IL-12 GEMs on gene expression profiles within the TME and tumor burden were evaluated in syngeneic mouse models of glioblastoma and melanoma and in human tumor slices isolated from patients with advanced gastrointestinal malignancies.

Results

Here, we present a cellular immunotherapy platform using lentivirus-driven genetic engineering of human and mouse macrophages to constitutively express proteins, including secreted cytokines and full-length checkpoint antibodies, as well as cytoplasmic and surface proteins that overcomes these barriers. GEMs traffic to, persist in, and express lentiviral payloads in xenograft mouse models of glioblastoma, and express a non-signaling truncated CD19 surface protein for elimination. IL-12-secreting GEMs activated T cells and induced interferon-gamma (IFNγ) in vitro and slowed tumor growth resulting in extended survival in vivo. In a syngeneic glioblastoma model, IFNγ signaling cascades were also observed in mice treated with mouse bone-marrow-derived GEMs secreting murine IL-12. These findings were reproduced in ex vivo tumor slices comprised of intact MEs. In this setting, IL-12 GEMs induced tumor cell death, chemokines and IFNγ-stimulated genes and proteins.

Conclusions

Our data demonstrate that GEMs can precisely deliver titratable doses of therapeutic proteins to the TME to improve safety, tissue penetrance, targeted delivery and pharmacokinetics.

Macrophages genetically engineered to secrete IL-12 induce tumor killing and immune activation in human tumor slice cultures

Cell-based immunotherapies for cancer, such as chimeric antigen receptor (CAR) T-cells, are effective against certain hematologic malignancies, but less reliably overcome the immunosuppressive tumor microenvironment (TME) of solid tumors to effectively cause cancer remission. Preclinical studies testing interleukin-12 (IL-12), an immune stimulating cytokine that activates T-cells and NK cells, as an anti-tumor agent have been promising. However, clinical trials have demonstrated that IL-12 is toxic if delivered systemically. To achieve local, low-dose delivery of IL-12, we have made genetically engineered macrophages (GEMs) to produce IL-12. In vitro, IL-12 GEMs stably produce IL-12 for at least one month. To evaluate their ability to stimulate an immune response and induce tumor cell death in an intact immune environment, we co-cultured them with tumor slices from both human colorectal cancer liver metastases and pancreatic ductal adenocarcinoma. In both tumor subtypes, the addition of IL-12 GEMs increased tumor cell death and generated an inflammatory response within the tumor slice, as evidenced by an increase in interferon-gamma and C-X-C Motif Chemokine Ligand 9 and 10, when compared to control GEMs. We demonstrate our GEM platform as a promising way to locally and sustainably deliver IL-12 to solid tumors to overcome the immunosuppressive TME.

Tumor slice culture as a biologic surrogate of human cancer

Background

The tumor microenvironment (TME) is critical to every aspect of cancer biology. Organotypic tumor slice cultures (TSCs) preserve the original TME and have demonstrated utility in predicting drug sensitivity, but the association between clinicopathologic parameters and in vitro TSC behavior has not been well-defined.

Methods

One hundred and eight fresh tumor specimens from liver resections at a tertiary academic center were procured and precisely cut with a Vibratome to create 250 μm × 6 mm slices. These fixed-dimension TSCs were grown on polytetrafluoroethylene inserts, and their metabolic activities were determined by a colorimetric assay. Correlation between baseline activities and clinicopathologic parameters was assessed. Tissue CEA mRNA expression was determined by RNAseq.

Results

By standardizing the dimensions of a slice, we found that adjacent tumor slices have equivalent metabolic activities, while those derived from different tumors exhibit >30-fold range in baseline MTS absorbances, which correlated significantly with the percentage of tumor necrosis based on histologic assessment. Extending this to individual cancers, we were able to detect intra-tumoral heterogeneity over a span of a few millimeters, which reflects differences in tumor cell density and Ki-67 positivity. For colorectal cancers, tissue CEA expression based on RNAseq of tumor slices was found to correlate with clinical response to chemotherapies.

Conclusions

We report a standardized method to assess and compare human cancer growth ex vivo across a wide spectrum of tumor samples. TSC reflects the state of tumor behavior and heterogeneity, thus providing a simple approach to study of human cancers with an intact TME.

Epidermoid Cyst within an Intrapancreatic Accessory Spleen Mimicking a Pancreatic Cystic Neoplasm

Although intra-abdominal accessory spleens are commonly found in 10-30% of the general population, epidermoid cyst within an intrapancreatic accessory spleen (ECIPAS) is an extremely rare entity and is often misdiagnosed preoperatively as a cystic malignancy. We present the case of a 51-year-old man who was referred to our clinic because of an incidentally found pancreatic tail cystic mass. Due to CA 19-9 level over 2000 and high suspicion of malignancy, the patient underwent distal pancreatectomy with splenectomy. Histopathological analysis revealed a squamous epithelial lining with splenic parenchyma within the cyst wall, which was consistent with ECIPAS. The patient was discharged on postoperative day 4 without any complication. As this disease may mimic malignancy with no characteristic features in preoperative imaging, it should be considered in the differential diagnosis of pancreatic cystic lesions.

Dendritic Cells in the Tumor Microenvironment

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) of the immune system. They capture foreign antigens and can present them to lymphocytes, that is, T cells and B cells, to activate them. DCs are the most potent of all immune cells at inducing the adaptive immune system. Thus, the presence of DCs at the anatomical site of the immune challenge is imperative for the immune system to mount an effective immune response. From the anatomical site of the immune challenge, DCs cargo antigens to the draining lymph nodes, specialized immune organs where adaptive immunity is generated. DCs are heterogeneous as a type of immune cell, and various subsets of DCs have been reported and their functions described. In this chapter, we discuss various aspects of DC development and function. We further discuss how various tumor microenvironments can affect DC development, function, and migration, thus evading a strong adaptive immune response.

The CXCL12-CXCR4/CXCR7 axis as a mechanism of immune resistance in gastrointestinal malignancies

Single agent checkpoint inhibitor therapy has not been effective for most gastrointestinal solid tumors, but combination therapy with drugs targeting additional immunosuppressive pathways is being attempted. One such pathway, the CXCL12-CXCR4/CXCR7 chemokine axis, has attracted attention due to its effects on tumor cell survival and metastasis as well as immune cell migration. CXCL12 is a small protein that functions in normal hematopoietic stem cell homing in addition to repair of damaged tissue. Binding of CXCL12 to CXCR4 leads to activation of G protein signaling kinases such as P13K/mTOR and MEK/ERK while binding to CXCR7 leads to β-arrestin mediated signaling. While some gastric and colorectal carcinoma cells have been shown to make CXCL12, the primary source in pancreatic cancer and peritoneal metastases is cancer-associated fibroblasts. Binding of CXCL12 to CXCR4 and CXCR7 on tumor cells leads to anti-apoptotic signaling through Bcl-2 and survivin upregulation, as well as promotion of the epithelial-to-mesechymal transition through the Rho-ROCK pathway and alterations in cell adhesion molecules. High levels of CXCL12 seen in the bone marrow, liver, and spleen could partially explain why these are popular sites of metastases for many tumors. CXCL12 is a chemoattractant for lymphocytes at lower levels, but becomes chemorepellant at higher levels; it is unclear exactly what gradient exists in the tumor microenvironment and how this influences tumor-infiltrating lymphocytes. AMD3100 (Plerixafor or Mozobil) is a small molecule CXCR4 antagonist and is the most frequently used drug targeting the CXCL12-CXCR4/CXCR7 axis in clinical trials for gastrointestinal solid tumors currently. Other small molecules and monoclonal antibodies against CXCR4 are being trialed. Further understanding of the CXCL12- CXCR4/CXCR7 chemokine axis in the tumor microenvironment will allow more effective targeting of this pathway in combination immunotherapy.

Challenges in assessing solid tumor responses to immunotherapy

With the advent of immunotherapy as an integral component of multidisciplinary solid tumor treatment, we are confronted by an unfamiliar and novel pattern of radiographic responses to treatment. Enlargement of tumors or even new lesions may not represent progression, but rather reflect what will ultimately evolve into a clinically beneficial response. In addition, the kinetics of radiographic changes in response to immunotherapy treatments may be distinct from what has been observed with cytotoxic chemotherapy and radiation. The phenomenon of pseudoprogression has been documented in patients receiving immunotherapeutic agents, such as checkpoint inhibitors and cellular therapies. Currently, there are no clinical response guidelines that adequately account for pseudoprogression and solid tumor responses to immunotherapy in general. Even so, response criteria have evolved to account for the radiographic manifestations of novel therapies. The evolution of World Health Organization (WHO) criteria and Response Evaluation Criteria in Solid Tumors (RECIST), along with the emergence of immune-related response criteria (irRC) and the immune Response Evaluation Criteria in Solid Tumors (iRECIST) reflect the need for new frameworks. This review evaluates the relationship between pseudoprogression, clinical outcomes, and our current understanding of the biology of pseudoprogression. To achieve our goal, we discuss unusual response patterns in patients receiving immunotherapy. We seek to develop a deeper understanding of radiographic responses to immunotherapy such that clinical benefit is not underappreciated in individual patients and during clinical investigation.

NCCN Guidelines Insights: Neuroendocrine and Adrenal Tumors, Version 2.2018

The NCCN Guidelines for Neuroendocrine and Adrenal Tumors provide recommendations for the management of adult patients with neuroendocrine tumors (NETs), adrenal gland tumors, pheochromocytomas, and paragangliomas. Management of NETs relies heavily on the site of the primary NET. These NCCN Guidelines Insights summarize the management options and the 2018 updates to the guidelines for locoregional advanced disease, and/or distant metastasis originating from gastrointestinal tract, bronchopulmonary, and thymus primary NETs.

Screening for Pancreatic Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Pancreatic adenocarcinoma is the third most common cause of cancer death among men and women in the United States.

OBJECTIVE

To systematically review benefits and harms of screening for pancreatic adenocarcinoma to inform the US Preventive Services Task Force.

DATA SOURCES

MEDLINE, PubMed, and the Cochrane Collaboration Registry of Controlled Trials, from January 2002 through April 27, 2018; surveillance through March 22, 2019.

STUDY SELECTION

Studies of adults with or without risk factors for pancreatic adenocarcinoma (eg, family history of pancreatic cancer, personal history of new-onset diabetes) undergoing imaging-based screening; studies of treatment for adults with screen-detected or asymptomatic pancreatic adenocarcinoma. Included study designs were randomized clinical trials, nonrandomized controlled intervention studies, diagnostic accuracy studies with a reference standard, cohort studies, and case-control studies (for evaluation of harms only). Studies consisting entirely of populations with known genetic syndromes associated with pancreatic cancer were excluded.

DATA EXTRACTION AND SYNTHESIS

Two investigators independently reviewed abstracts and full-text articles and rated included studies for quality; data were quantitatively analyzed to calculate a pooled diagnostic yield and narratively synthesized.

MAIN OUTCOMES AND MEASURES

Mortality, morbidity, or quality of life; diagnostic accuracy of screening tests; any harm of screening or treatment.

RESULTS

Thirteen fair-quality prospective cohort screening studies (N = 1317) conducted predominantly in populations at high familial risk for pancreatic adenocarcinoma were included. No studies reported on the effect of screening on morbidity or mortality or on the effectiveness of treatment for screen-detected pancreatic adenocarcinoma. Although no studies evaluated the diagnostic accuracy of screening tests, all 13 studies reported the diagnostic yield. Yields ranged from 0 to 75 cases per 1000 persons in studies using endoscopic ultrasound, magnetic resonance imaging, and/or computed tomography-based screening. In total, 18 cases of pancreatic adenocarcinoma were detected in 1156 adults at increased familial risk and 0 cases were detected in 161 average-risk adults. In 8 studies (n = 675) assessing procedural harms of screening, no serious harms from initial screening were reported. Two studies (n = 271) found no evidence of psychosocial harms related to screening. Evidence of surgical harms was limited.

CONCLUSIONS AND RELEVANCE

Imaging-based screening in groups at high familial risk can detect pancreatic adenocarcinoma with limited evidence of minimal harms. However, the effect of screening on morbidity and mortality in groups at high familial risk has not been studied, and no data are available in average-risk populations. There is limited evidence to assess benefits or harms of surgical intervention for screen-detected pancreatic adenocarcinoma.

Abstract 4489: IL-10 blockade reactivates antitumor immunity in human colorectal cancer liver metastases

Background: Colorectal cancer (CRC) is the 4th most common cancer in the US, and the liver is the most common site of metastatic disease. Immune checkpoint inhibitor therapy has not been successful in achieving a clinical response in most patients with CRC liver metastases (CRCLM). The liver is known to induce tolerance to foreign antigens as a result of immunosuppressive cytokines including IL-10. We hypothesized that blockade of IL-10 signaling in CRCLM would potentiate tumor infiltrating lymphocyte (TIL)-mediated tumor cell death.

Methods: We performed single-cell RNA sequencing (scRNAseq) of CRCLM using the 10x platform to evaluate for expression of IL-10 or IL-10 receptor (IL-10R) RNA within the tumor (n=8). To confirm if the IL-10R protein was present within the tumor microenvironment (TME), we also performed immunohistochemistry (IHC) (n=3). In order to study the functional effects of IL-10 blockade, we utilized a tumor slice culture (TSC) model, which allows for the study of cancers with their intact TME including immune cells. For TSCs, cores (6 mm diameter) were taken from freshly resected sterile human CRCLM and cut to 250 µm thick slices using a vibratome (n=3). Duplicate slices were treated with either IgG control or anti-IL-10 monoclonal antibodies and cultured for up to 6 days. To evaluate for histological evidence of necrosis and cell apoptosis within the tumor slice, we stained slides with either hematoxylin and eosin (H&E) or cleaved-Caspase-3 (CC3). To gain insight into the activation state of TIL after treatment, we measured levels of cytokines within the culture supernatants.

Results: We found by scRNAseq that that IL-10 was expressed by a subset of tumor-associated macrophages, and IL-10R was expressed by both CD4+ and CD8+ T cells as well as macrophages. We confirmed that IL-10R protein was present within the CRCLM TME by IHC, and IL-10R expression was distributed throughout the stroma in non-tumor cells. In TSC treated with anti-IL-10 antibody, CC3+ cells were found to be 82.8% of total cells, compared to 36.1% of control (p = 1 x 10-6) at day 6. These findings were consistent across all human tumor samples treated with IL-10 blockade versus control at all time points examined. Furthermore, IL-10 blockade led to histologic evidence of generalized necrosis compared to an intact TME seen in the control group. Analysis of cytokines released into the media confirmed that IL-10 was present in controls, but absent in slices blocked with anti-IL-10 antibody. We also found increased levels of granzyme B, IL-2, GM-CSF, and IL-18, as well as a reduction in the immune checkpoint receptor TIM3, after one day of IL-10 blockade in culture.

Conclusion: Treatment of human CRCLM TSCs with anti-IL-10 antibody leads to a marked increase in immune-mediated cell death within the tumor. Our data suggest that IL-10 serves as a critical regulator of anti-tumor immunity in the CRCLM TME and may serve as an important immunotherapeutic target.

Citation Format: Kevin M. Sullivan, Xiuyun Jiang, Yongwoo David Seo, Heidi L. Kenerson, Xiaowei Yan, Chris Lausted, Changting Meng, Neda Jabbari, Kevin P. Labadie, Sara K. Daniel, Qiang Tian, Teresa S. Kim, Raymond S. Yeung, Venu G. Pillarisetty. IL-10 blockade reactivates antitumor immunity in human colorectal cancer liver metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4489.

Systemic Interferon-γ Increases MHC Class I Expression and T-cell Infiltration in Cold Tumors: Results of a Phase 0 Clinical Trial

Interferon-γ (IFNγ) has been studied as a cancer treatment with limited evidence of clinical benefit. However, it could play a role in cancer immunotherapy combination treatments. Despite high expression of immunogenic cancer-testis antigens, synovial sarcoma (SS) and myxoid/round cell liposarcoma (MRCL) have a cold tumor microenvironment (TME), with few infiltrating T cells and low expression of major histocompatibility complex class I (MHC-I). We hypothesized that IFNγ treatment could drive inflammation in a cold TME, facilitating further immunotherapy. We conducted a phase 0 clinical trial treating 8 SS or MRCL patients with weekly systemic IFNγ. We performed pre- and posttreatment biopsies. IFNγ changed the SS and MRCL TME, inducing tumor-surface MHC-I expression and significant T-cell infiltration (P < 0.05). Gene-expression analysis suggested increased tumor antigen presentation and less exhausted phenotypes of the tumor-infiltrating T cells. Newly emergent antigen-specific humoral and/or T-cell responses were found in 3 of 7 evaluable patients. However, increased expression of PD-L1 was observed on tumor-infiltrating myeloid cells and in some cases tumor cells. These findings suggest that systemic IFNγ used to convert SS and MRCL into "hot" tumors will work in concert with anti-PD-1 therapy to provide patient benefit.

Mobilization of CD8+ T Cells via CXCR4 Blockade Facilitates PD-1 Checkpoint Therapy in Human Pancreatic Cancer

PURPOSE

Pancreatic ductal adenocarcinoma (PDA) is rarely cured, and single-agent immune checkpoint inhibition has not demonstrated clinical benefit despite the presence of large numbers of CD8⁺ T cells. We hypothesized that tumor-infiltrating CD8⁺ T cells harbor latent antitumor activity that can be reactivated using combination immunotherapy.

EXPERIMENTAL DESIGN

Preserved human PDA specimens were analyzed using multiplex IHC (mIHC) and T-cell receptor (TCR) sequencing. Fresh tumor was treated in organotypic slice culture to test the effects of combination PD-1 and CXCR4 blockade. Slices were analyzed using IHC, flow cytometry, and live fluorescent microscopy to assess tumor kill, in addition to T-cell expansion and mobilization.

RESULTS

mIHC demonstrated fewer CD8⁺ T cells in juxtatumoral stroma containing carcinoma cells than in stroma devoid of them. Using TCR sequencing, we found clonal expansion in each tumor; high-frequency clones had multiple DNA rearrangements coding for the same amino acid binding sequence, which suggests response to common tumor antigens. Treatment of fresh human PDA slices with combination PD-1 and CXCR4 blockade led to increased tumor cell death concomitant with lymphocyte expansion. Live microscopy after combination therapy demonstrated CD8⁺ T-cell migration into the juxtatumoral compartment and rapid increase in tumor cell apoptosis.

CONCLUSIONS

Endogenous tumor-reactive T cells are present within the human PDA tumor microenvironment and can be reactivated by combined blockade of PD-1 and CXCR4. This provides a new basis for the rational selection of combination immunotherapy for PDA.See related commentary by Medina and Miller, p. 3747.

Hypoxia as a barrier to immunotherapy in pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) is a lethal disease with limited response to cytotoxic chemoradiotherapy, as well as newer immunotherapies. The PDA tumor microenvironment contains infiltrating immune cells including cytotoxic T cells; however, there is an overall immunosuppressive milieu. Hypoxia is a known element of the solid tumor microenvironment and may promote tumor survival. Through various mechanisms including, but not limited to, those mediated by HIF-1α, hypoxia also leads to increased tumor proliferation and metabolic changes. Furthermore, epithelial to mesenchymal transition is promoted through several pathways, including NOTCH and c-MET, regulated by hypoxia. Hypoxia-promoted changes also contribute to the immunosuppressive phenotype seen in many different cell types within the microenvironment and thereby may inhibit an effective immune system response to PDA. Pancreatic stellate cells (PSCs) and myofibroblasts appear to contribute to the recruitment of myeloid derived suppressor cells (MDSCs) and B cells in PDA via cytokines increased due to hypoxia. PSCs also increase collagen secretion in response to HIF-1α, which promotes a fibrotic stroma that alters T cell homing and migration. In hypoxic environments, B cells contribute to cytotoxic T cell exhaustion and produce chemokines to attract more immunosuppressive regulatory T cells. MDSCs inhibit T cell metabolism by hoarding key amino acids, modulate T cell homing by cleaving L-selectin, and prevent T cell activation by increasing PD-L1 expression. Immunosuppressive M2 phenotype macrophages promote T cell anergy via increased nitric oxide (NO) and decreased arginine in hypoxia. Increased numbers of regulatory T cells are seen in hypoxia which prevent effector T cell activation through cytokine production and increased CTLA-4. Effective immunotherapy for pancreatic adenocarcinoma and other solid tumors will need to help counteract the immunosuppressive nature of hypoxia-induced changes in the tumor microenvironment. Promising studies will look at combination therapies involving checkpoint inhibitors, chemokine inhibitors, and possible targeting of hypoxia. While no model is perfect, assuring that models incorporate the effects of hypoxia on cancer cells, stromal cells, and effector immune cells will be crucial in developing successful therapies.