Tumor Parenchyma Research Articles

OTHR-09. A RETROSPECTIVE COHORT STUDY EXAMINING RADIOLOGIC AND CLINICAL CHARACTERISTICS OF CHILDREN AND ADOLESCENTS WITH ATYPICAL/COMPLEX PINEAL CYSTS

Abstract INTRODUCTION The significance of atypical or complex pineal cysts (CPC) on magnetic resonance imaging (MRI) is often unclear, and the appropriate management has not been well defined. We conducted a retrospective cohort study of children and adolescents (0-18 years of age) with complex pineal cysts noted on brain MRIs obtained at Children’s Hospital Los Angeles (CHLA) prior to 05/31/2022. METHODS We retrospectively reviewed electronic medical records at CHLA to identify patients <18 years of age who were diagnosed with CPC upon MRI between January 1, 2010 and May 31, 2022. CPC were defined as cysts that are multi-cystic, enhancing, ≥1 cm in size, have a solid component, or exhibit restricted diffusion. Patients were identified by an automated Boolean search of a radiology report database; individual reports were then reviewed for eligibility. Patients with normal pineal glands or simple (<1 cm) pineal cysts were excluded. Electronic medical records were evaluated for patient chief complaint, initial clinical and radiographic symptoms, tumor markers (beta-human chorionic gonadotropin and alpha-fetoprotein), and final diagnosis. RESULTS We identified a cohort of 175 patients; 106 (61%) were female. Mean age at initial MRI was 8.36 years of age (SD 5.36). Tumor markers were measured in 52 patients (30%). The most common presenting symptoms for patients were headache (34%), seizures (26%), nausea/vomiting (19%), weakness/fatigue (17%), and dizziness (12%). Additional presenting symptoms included ataxia, sensory changes, and anxiety. Pineal malignancies were identified in 4 patients (2.2%), which consisted of a pituitary pure germinoma, a pineal region parenchymal tumor, and two pineoblastomas. The remaining 98% of patients (171 patients) either had a benign pineal cyst or were categorized as unknown. CONCLUSION Most CPC are not associated with malignant neoplasms and represent incidental findings with scant clinical significance.

DIPG-16. ACUTE VERSUS PROLONGED CONVECTION-ENHANCED DELIVERY OF ALISERTIB INTO H3 K27M-MUTANT MODELS OF DIFFUSE MIDLINE GLIOMA

Abstract Convection-enhanced delivery (CED) is a potentially promising strategy to administer therapeutics directly into the brainstem of children harboring H3 K27-altered diffuse midline glioma (DMG). While early-phase clinical trials have demonstrated the safety of this technique, efficacy has yet to be achieved. Here, we describe how different variations of CED may be exploited to extend survival in a DMG murine patient-derived orthotopic xenograft model. Either 1-day (8 µL/hr) or 7-day (1 µL/hr) continuous CED infusions were performed to deliver an equivalent volume of the aurora kinase inhibitor alisertib to the mouse brainstem. Bioluminescence and magnetic resonance images were acquired to monitor tumor progression, validate CED catheter positioning, and analyze infusion-related imaging changes. Both infusion regimens significantly prolonged survival versus control (median survival benefit of 6.5 and 8 days, p=0.03 and p=0.01, for 1-day and 7-day CED, respectively). Postmortem examination of brains revealed no signs of tissue necrosis, cavitary lesions, or cellular (inflammatory) infiltrate at the site of infusion. However, the tumor parenchyma surrounding the cannula tract was markedly hypocellular in treated animals. Alisertib induced a robust increase in H3 K27 trimethylation along with decreased H3 K27M and Ki-67. Our findings indicate that CED of alisertib is well tolerated and effective, in both the acute and prolonged setting, underscoring the potential of this approach in the management of DMG.

Positive Progesterone Receptor Expression in Meningioma May Increase the Transverse Relaxation: First Prospective Clinical Trial Using Single-Shot Ultrafast T2 Mapping

Rationale and ObjectivesThis project aims to investigate the diagnostic performance of multiple overlapping-echo detachment imaging (MOLED) technique-derived transverse relaxation time (T2) maps in predicting progesterone receptor (PR) and S100 expression in meningiomas. Materials and Methods63 meningioma patients were enrolled from October 2021 to August 2022, who underwent a complete routine magnetic resonance imaging and T2 MOLED, which can characterize the whole brain transverse relaxation time within 32 seconds in a single scan. After the surgical resection of meningiomas, the expression levels of PR and S100 were determined by an experienced pathologist using immunohistochemistry techniques. Histogram analysis was performed in tumor parenchyma based on the parametric maps. Independent t test and Mann-Whitney U test were applied for the comparison of histogram parameters between different groups, with a significance level of P < .05. Logistic regression and receiver operating characteristic (ROC) analysis with 95% confidence interval were conducted for the diagnostic efficiency evaluation. ResultsPR-positive group had significantly elevated T2 histogram parameters (P = .001-.049) compared to the PR-negative group. The multivariate logistic regression model with T2 showed the highest area under the ROC curve (AUC) for predicting PR expression (AUC=0.818). Additionally, the multivariate model also had the best diagnostic performance for predicting meningioma S100 expression (AUC=0.768). ConclusionThe MOLED technique-derived T2 maps can distinguish PR and S100 status in meningiomas preoperatively.

QUANTIFICATION OF ABSORBED DOSE IN 90Y SELECTIVE INTERNAL RADIATION THERAPY FOR HEPATOCELLULAR CARCINOMA TREATMENT: A REVIEW

Selective internal radiation therapy (SIRT) has emerged as a viable strategy for the treatment of incurable hepatic cancers. Although SIRT is a well-known therapy, continuous improvement in personalised dosimetry is required to improve the treatment planning and delivery of therapy. The ability to precisely foresee, plan, and administer the ideal dose to the tumour and non-tumoral tissues, including a final validation of the dose distribution, is the primary principle of radiation. The main way for safely personalised therapy for a maximum response while respecting normal tissue tolerances is to know the true absorbed dose to tissue compartments. Recent clinical studies highlighted the significance of personalised dosimetry to make it safer and more effective. Quantification of the absorbed dose distribution is of utmost importance in SIRT 90Y to optimise the hepatocellular carcinoma (HCC) treatment. The aim of this article was to review various dosimetric approaches in quantifying the absorbed dose of tumours and healthy liver tissue in 90Y SIRT. This article also compares the capabilities of organ-level dosimetry, voxel-level dosimetry and Monte Carlo simulation in assessing the absorbed dose in organs especially liver. The quantification of absorbed dose influences 90Y SIRT tumour dosimetry, while healthy liver absorbed dose values were comparable for all investigated imaging data. Personalised dosimetry for the tumour and healthy liver parenchyma after 90Y SIRT is recommended for patient-tailored therapy with enhanced therapeutic outcomes and for the safe administration of additional treatment cycles.

Genomic profiles of chromosome remodeling pathway and their correlation with TMB, MSI, PD-L1, and immune microenvironment in biliary tract tumors.

e16181 Background: Immunotherapy combined with chemotherapy has become a promising first-line treatment for biliary tract tumor (BTC) patients. A previous clinical trial with a small sample size revealed that impaired functions of chromatin remodeling genes might be a potential predictive biomarker of combined immunotherapy for BTC. However, genomic profiles of chromosome remodeling pathway and their correlation with tumor mutation burden (TMB), microsatellite instability (MSI), programmed death ligand-1 (PD-L1) and immune microenvironment in Chinese BTC patients remain unknown. Methods: A total of 2031 BTC patients (cholangiocarcinoma [CCA], N=1476; gallbladder carcinoma [GBC], N=555) were included in this study, and their tumor tissue samples were subject to next generation sequencing using a 733-gene panel. Multiple immunofluorescence using for immune microenvironment related markers (including PD-1, PD-L1, CD8, CD68, CD163, CD3, CD4, CD20, CD56 and FoxP3) detection was conducted in 49 patients. Prognostic survival data were obtained from two clinical sequencing cohorts (CCA: ICGC-2017, N=417; GBC: MSK-2022, N=233) and were used to explore the association between chromatin remodeling genes mutation and prognosis. Results: In total, 57.9% (1175/2031) of BTC patients harbored alternations in genes involved in chromatin remodeling pathway and the top three alteration frequency somatic genes were ARID1A (19%), KMT2C (11%), ARID2/KMT2D/PBRM1 (8% each), respectively. The commonly alternation types were missense (48%), frameshift indel (25%) and nonsense (17%), respectively. The TMB level of altered group was significantly higher than wild group (median TMB, mutant-type vs. wild-type = 6.145 vs. 3.352 Muts/Mb, P&lt;0.0001), but no significant difference was found in the PD-L1 expression level between the two groups. A total of 43 patients were identified as MSI-high, all of whom harbored alternations in genes involved in chromatin remodeling pathway. Compared with the wild group, the infiltration level of CD20+ B cells in tumor parenchyma was significantly higher in the altered group. Furthermore, there was no difference in overall survival (OS) between altered group and wild group (median OS, 18.99 vs. 20.97 months; HR=1.164 [95%CI: 0.9048-1.498], P=0.2360) in two clinical sequencing cohorts without immunotherapy. Conclusions: The results revealed the molecular basis of chromosome remodeling genes as the predictive biomarker of combined immunotherapy for BTC and exclude its effect on prognosis.

Immune infiltrates in metastatic uveal melanoma liver metastases and associations with clinical outcomes.

9538 Background: Uveal melanoma has a poor prognosis following metastasis to the liver. Immune checkpoint inhibitors (ICIs) are often utilized in patients with metastatic uveal melanoma (MUM); however, ICIs in MUM have low response rates. We studied the association of immune infiltrates in MUM liver metastases with survival outcomes for all patients, in addition to evaluating if immune infiltrates improve survival for patients treated with ICIs. Methods: We included MUM patients with liver metastases who had pre-treatment liver biopsies available at Mayo Clinic Rochester. Demographics, disease characteristics, treatments, and clinical outcomes were obtained from the electronic medical record. Core biopsies of liver metastases were reviewed for the presence of lymphocytes at interface of the tumor and liver parenchyma, and for tumor-infiltrating lymphocytes (TILs). If TILs were present, then additional immunohistochemistry (IHC) staining was performed for CD3, CD4, CD8, PD1, CD25, and FoxP3. Overall survival (OS) was estimated with the Kaplan-Meier method and compared between groups with Cox proportional hazards regression. Median OS and hazard ratios (HR) were calculated and p-values (p) &lt;0.05 were considered statistically significant. Results: 140 patients with MUM who had pre-treatment liver biopsies were identified. 122 biopsies were evaluable for the presence of lymphocytes, either at the tumor-liver interface, or for TILs. 80/122 (65.6%) biopsies showed presence of any lymphocyte and 27/80 had TILs. 27 biopsies had sufficient tissue for further IHC classification. CD8+ T cells were identified in 27/27 samples, T cell PD1 positivity ≥1% in 4/27 samples, and regulatory T cell markers (CD25 and/or FoxP3) in 18/27 samples. Median OS for the entire cohort was 16 months (mo). Patients still alive at the time of data analysis had at least one year of follow-up available (range 13-124 mo). Univariate analyses (UVA) showed no significant improvement in OS based on the presence of any lymphocytes (HR 1.01, p 0.98), lymphocytes at the tumor-liver interface (HR 1.10, p 0.64), TILs (HR 0.78, p 0.27), &gt;50% CD8+ T cells (HR 0.88, p 0.77), or absence of FoxP3+ T cells (HR 0.68, p 0.40). In the 69 patients treated with ICIs (pembrolizumab, nivolumab, or ipilimumab plus nivolumab), neither the presence of any lymphocytes (HR 1.19, p 0.56) nor TILs (HR 0.68, p 0.24) were associated with an OS benefit. Conclusions: We present a large cohort of patients with MUM where we characterized immune infiltrates in liver metastases and evaluated clinical outcomes. OS did not significantly improve with the presence of any lymphocytes, TILs, CD8+ T cells, or with the absence of FoxP3+ T cells. These results were consistent across all patients whether they were treated with ICIs or not. Our findings suggest that lymphocytes in MUM are functionally dormant and highlights the need for novel immune-activating treatment strategies.

AMD3100-Mediated CXCR4 Inhibition Impairs Development of Primary Lymphoma of the Central Nervous System

A hallmark of primary lymphoma of the central nervous system (CNS; PCNSL) is the strong CXCR4 expression of the tumor cells, the function of which is still unknown. Invitro treatment of BAL17CNS lymphoma cells by AMD3100, which inhibits CXCR4-CXCL12 interactions, resulted in the significantly differential expression of 273 genes encoding proteins involved in cell motility, cell-cell signaling and interaction, hematological system development and function, and immunologic disease. Among the genes down-regulated was the one encoding CD200, a regulator of CNS immunologic activity. These data directly translated into the invivo situation; BAL17CNS CD200 expression was down-regulated by 89% (3% versus 28% CD200+ lymphoma cells) in AMD3100-treated versus untreated mice with BAL17CNS-induced PCNSL. Reduced lymphoma cell CD200 expression may contribute to the markedly increased microglial activation in AMD3100-treated mice. AMD3100 also maintained the structural integrity of blood-brain barrier tight junctions and the outer basal lamina of cerebral blood vessels. Subsequently, lymphoma cell invasion of the brain parenchyma was impaired, and maximal parenchymal tumor size was significantly reduced by 82% in the induction phase. Thus, AMD3100 qualified as a potentially attractive candidate to be included into the therapeutic concept of PCNSL. Beyond therapy, CXCR4-induced suppression of microglial activity is of general neuroimmunologic interest and identifies CD200 expressed by the lymphoma cells as a novel mechanism of immune escape in PCNSL.

Onconephrology: Renal cancer

Renal cancer (RC) ranks eighth among the most prevalent oncopathologies, making it one of the most widespread types of cancer. Over the last decade, there has been an average annual increase in morbidity of 2 percent. RC is a collective term that encompasses parenchymal tumors and pelvis tumors with distinct histologic characteristics.&#x0D; Renal cancer can appear in intact kidneys and cause additional damage except for the actual tumor process, or in patients with previously affected kidneys.&#x0D; The main treatment option for renal cell carcinoma (RCC) is surgery, which can be performed through various approaches, including open-access surgery, laparoscopic surgery, and robotic-assisted surgery. These surgical techniques enable the performance of radical nephrectomy, partial nephrectomy, and cytoreductive nephrectomy. The selection of the surgical method and the extent of the intervention fall within the expertise of oncourologists.&#x0D; Anti-angiogenic drugs, including tyrosine kinase inhibitors, humanized monoclonal antibodies, and immune checkpoint inhibitors, as well as mTOR inhibitors, are commonly utilized in the treatment of advanced-stage RCC (II-IV) or its relapse. However, it is important to note that these drugs possess considerable nephrotoxicity. Therefore, kidney status plays a crucial role in determining the appropriate treatment options, the dosage of antitumor drugs, and the potential nephrotoxicity associated with them, thereby becoming the main limiting factor affecting the quality and duration of life for RCC patients.&#x0D; The present review focuses on the analysis of recent data concerning the issues mentioned above, primarily in relation to RCC, and provides recommendations for the investigation and treatment of this specific category of patients.

Prostate-Specific Membrane Antigen (PSMA) Expression in The Neovasculature of High Grade Gliomas (Histopathological and Immunohistochemical Study).

Prostate-specific membrane antigen (PSMA) was first noticed in prostate cancer cells, thereafter, It has been found in the endothelial cells of neovasculature in a variety of tumors, but not in normal vascular endothelium, This specificity makes PSMA an ideal molecule for vascular targeting in Cancer theranostics (i.e., combined diagnostic and therapeutic). The objective of this study was to evaluate the immunohistochemical (IHC) expression of PSMA in the neovasculature (identified by CD 31) of high-grade gliomas (HGGs) and to Correlate PSMA IHC expression in HGGs with clinicopathological features, to detect its possible role in tumor angiogenesis, where PSMA can be used as a future diagnostic and therapeutic target. This retrospective study included a total of 69 archived, formalin-fixed, paraffin-embedded tissue blocks of HGGs, including 52 cases classified as WHO grade IV (75.4%) and 17 cases as WHO grade III (24.6%). The samples were immunohistochemically analyzed for PSMA expression (in both TMV and parenchymal tumor cells) which was assessed using the composite PSMA immunostaining score. A score (0) was considered negative while scores 1-7 were considered positive (1-4, 5-6, or 7; weak, moderate, or strong respectively). PSMA is expressed specifically and significantly in endothelial cells of tumor microvessels (TMV) of HGGs, A statistically significant relationship was detected between PSMA IHC expression in both TMV and in parenchymal tumor cells (TC) and various glioma subtypes (P-value < 0.05 and <0.001 respectively). Positive PSMA immunostaining in TMV was detected in all anaplastic ependymoma cases and in near all cases of classic GB and GB with oligodendroglial features more than other subtypes, with P-value specifically for PSMA positivity/negativity in TMV statistically significant (0.022). While for Tumor cells, Positive PSMA immunostaining was detected in all anaplastic ependymoma, most anaplastic astrocytoma and classic GB cases in contrary to other variants, with P-value statistically extremely significant (< 0.001). Comparing PSMA IHC expression in TMV and its expression in TC, it was significantly expressed in TMV of 82.7% versus TC of 51.9% of grade IV cases. Likewise, in GB with oligodendroglial features and gliosarcoma, the majority of cases showed positive staining in their TMV [8/8 (100%), 9/13 (69.2%) respectively], and, the reverse occurs in tumor cells where the majority of cases did NOT show staining in the tumor cells for PSMA (5/8 (62.5%), 11/13 (84.6%) of cases respectively), which was statistically significant (P-value ≤ 0.05) besides the significant difference in the pattern of staining according to composite PSMA scoring (P-value ≤ 0.05). PSMA has a possible role in tumor angiogenesis, therefore it might be considered a potential promising endothelial target for Cancer theranostics with PSMA-based agents, in addition, PSMA was expressed significantly in TC of HGGs, thus, it appears to be involved in biologic behavior, carcinogenesis and tumor progression.

Quantitative susceptibility mapping evaluation of glioma.

To comprehensively evaluate the glioma using quantitative susceptibility mapping (QSM). Forty-two patients (18 women; mean age, 45years) with pathologically confirmed gliomas were retrospectively included. All the patients underwent conventional and advanced MRI examinations (QSM, DWI, MRS, etc.). Five patients underwent paired QSM (pre- and post-enhancement). Four Visually Accessible Rembrandt Image (VASARI) features and intratumoural susceptibility signal (ITSS) were observed. Three ROIs each were manually drawn separately in the tumour parenchyma with relatively high and low magnetic susceptibility. The association between the tumour's magnetic susceptibility and other MRI parameters was also analysed. Morphologically, gliomas with heterogeneous ITSS were more similar to high-grade gliomas (p = 0.006, AUC: 0.72, sensitivity: 70%, and specificity: 73%). Heterogeneous ITSS was significantly associated with tumour haemorrhage, necrosis, diffusion restriction, and avid enhancement but did not change between pre- and post-enhanced QSM. Quantitatively, tumour parenchyma magnetic susceptibility had limited value in grading gliomas and identifying IDH mutation status, whereas the relatively low magnetic susceptibility of the tumour parenchyma helped identify oligodendrogliomas in IDH mutated gliomas (AUC = 0.78) with high specificity (100%). The relatively high tumour magnetic susceptibility significantly increased after enhancement (p = 0.039). Additionally, we found that the magnetic susceptibility of the tumour parenchyma was significantly correlated with ADC (r = 0.61) and Cho/NAA (r = 0.40). QSM is a promising candidate for the comprehensive evaluation of gliomas, except for IDH mutation status. The magnetic susceptibility of tumour parenchyma may be affected by tumour cell proliferation. • Morphologically, gliomas with a heterogeneous intratumoural susceptibility signal (ITSS) are more similar to high-grade gliomas (p = 0.006; AUC, 0.72; sensitivity, 70%; and specificity, 73%). Heterogeneous ITSS was significantly associated with tumour haemorrhage, necrosis, diffusion restriction, and avid enhancement but did not change between pre- and post-enhanced QSM. • Tumour parenchyma's relatively low magnetic susceptibility helped identify oligodendroglioma with high specificity. • Tumour parenchyma magnetic susceptibility was significantly correlated with ADC (r = 0.61) and Cho/NAA (r = 0.40).

Efficacy of three-dimensional arterial spin labeling and how it compares against that of contrast enhanced magnetic resonance imaging in preoperative grading of brain gliomas.

To evaluate the efficacy of three-dimensional arterial spin labeling (3D-ASL) imaging in preoperative grading of brain gliomas, and compare the discrepancy between images obtained from 3D-ASL and contrast enhanced magnetic resonance imaging (CE-MRI) in grading of gliomas. Fifty-one patients with brain gliomas received plain MRI, CE-MRI and 3D-ASL scanning before surgery. In 3D-ASL images, the maximum tumor blood flow (TBF) of tumor parenchyma was measured, relative TBF-M and rTBF-WM were calculated. The cases were categorized into "ASL dominant" and "CE dominant" to compare the discrepancy between 3D-ASL and CE-MRI results. Independent samples t test, Mann-Whitney and U test and one-way analysis of variance (ANOVA) were performed to test the differences of TBF, rTBF-M and rTBF-WM values among brain gliomas with different grades. Spearman rank correlation analysis was performed to assess the correlation between TBF, rTBF-M, rTBF-WM and glioma grades respectively. To compare the discrepancy between 3D-ASL and CE-MRI results. In high-grade gliomas (HGG) group, TBF, rTBF-M and rTBF-WM values were higher than those in low-grade gliomas (LGG) group (p < .05). Multiple comparison showed TBF and rTBF-WM values were different between grade I and IV gliomas, grade II and IV gliomas (both p < .05), the rTBF-M value was different between grade I and IV gliomas (p < .05). The values of all 3D-ASL derived parameters were positively correlated with gliomas grading (all p < .001). TBF showed highest specificity (89.3%) and rTBF-WM showed highest sensitivity (96.4%) when discriminating LGG and HGG using ROC curve. There were 29 CE dominant cases (23 cases were HGG), 9 ASL dominant cases (4 cases were HGG). CONCLUSION: 3D-ASL is of significance to preoperative grading of brain gliomas and might be more sensitive than CE-MRI in detection of tumor perfusion.

Prognostic and predictive factors in urothelial carcinomas: tumor parenchyma part 2

Prognostic and predictive factors in urothelial carcinomas: tumor parenchyma part 2

Abstract 2108: High prevalence of immune exclusion in cancer as determined by pathologist assessment and image analysis

Abstract Background: Immune infiltrated tumors have high levels of lymphocytes contacting tumor cells and are more responsive to checkpoint inhibitors. Tumors with few lymphocytes in contact with tumor cells can be divided into desert or excluded phenotypes based on lymphocyte absence/paucity or restriction to the peritumoral stroma, respectively. Standard methods to systematically identify and characterize immune exclusion for patient stratification are lacking. Methods: Slides from colorectal (CRC), non-small cell lung (NSCLC), ovarian (OC), pancreatic (PDAC), and triple-negative breast cancers (TNBC), and leiomyosarcoma (LMS) and undifferentiated pleomorphic sarcoma (UPS) were stained with multiplex IHC (mIHC) for CD8 and panCK. Pathologist assessment (PA) was done to classify the tumors as: desert, with a paucity of CD8 T cells; excluded, with CD8 T cells not penetrating the tumor parenchyma; and infiltrated, with CD8 T cells within the tumor parenchyma. For the carcinomas, adjacent sections were stained with a multiplex immunofluorescence (mIF) panel containing CD8 and a tumor cell marker. Image analysis (IA) was performed on the mIF images to quantify CD8 cell density in the tumor parenchyma and stroma to categorize immune phenotypes. Results: Immune phenotypes were classified for 143 samples based on PA of mIHC images and 103 samples by IA of mIF images (see Table 1). Immune exclusion as determined by both PA and IA was highest in CRC, PDAC, and TNBC. IA differed from PA in 25 (24.3%) cases. Pathologist review of the discordant cases revealed discrepancies were generally due to tumor heterogeneity, thresholding, assessment of cells at the tumor-stroma boundaries, necrosis, and artifacts. Conclusion: Immune exclusion is highly prevalent in the examined carcinoma types. IA-based approaches, guided by pathologist input, offer promise to quantitatively determine tumor immune phenotypes in a quick and systematic way to guide patients to the most effective therapy. Table 1. Pathologist Assessment Classification Image Analysis Classification Tumor Type n Desert (%) Excluded (%) Infiltrated % Desert (%) Excluded (%) Infiltrated % CRC 20 3 (15.0) 14 (70.0) 3 (15.0) 6 (30.0) 11 (55.0) 3 (15.0) NSCLC 21 6 (28.6) 12 (57.1) 3 (14.3) 6 (28.6) 9 (42.9) 6 (28.6) OC 20 3 (15.0) 9 (45.0) 8 (40.0) 9 (45.0) 3 (15.0) 8 (40.0) PDAC 21 6 (28.6) 14 (66.7) 1 (4.8) 7 (33.3) 12 (57.1) 2 (9.5) TNBC 21 3 (14.3) 15 (71.4) 3 (14.3) 4 (19.0) 10 (47.6) 7 (33.3) LMS 20 3 (15.0) 1 (5.0) 16 (80.0) NA NA NA UPS 20 4 (20.0) 1 (5.0) 15 (75.0) NA NA NA Total 143/103 28 (19.6) 66 (46.2) 49 (34.3) 32 (31.1) 45 (43.7) 26 (25.2) Citation Format: Florent Peyraud, Fredrick D. Gootkind, Antoine Italiano, Alban Bessede, Jean-Philippe Guegan, Xinwei Sher, Thomas Schürpf, Guy T. Clifton, Laura A. Dillon. High prevalence of immune exclusion in cancer as determined by pathologist assessment and image analysis [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 2108.

Abstract 4706: Multispectral immunofluorescence analysis of the olfactory neuroblastoma tumor immune microenvironment reveals macrophage and polymorphonuclear leukocyte stroma localization and tumor parenchyma exclusion

Abstract Background: Olfactory neuroblastoma (ONB), also known as esthesioneuroblastoma, is a rare malignancy of the nasal cavity and anterior skull base. Multispectral immunofluorescence (mxIF), allows for comprehensive evaluation of tumor immune cell spatial relationships and thorough characterization of the tumor immune microenvironment (TIME). The objective of this study was to comprehensively define the ONB myeloid cell TIME with mxIF. Methods: A tissue microarray including 47 clinically annotated human ONB samples was obtained, in addition to IRB approval, from our tertiary care hospital. A myeloid specific panel was validated in ONB tissue as well as controls. The panel stained for CD15, CD68, CD11b, CD14, HLA-DR, synaptophysin, and DAPI. Phenotypes of interest included CD11b+/CD15+/CD14−/HLA-DRlow/− polymorphonuclear leukocytes (PMNs), CD11b+/CD14+/CD15−/HLA-DR low/−monocytes, and CD68+ Pan Macrophages. HALO image analysis v3.4 was used to objectively quantify immune cell spatial relationships. A retrospective chart review was performed from these clinically annotated specimens with collection of patient demographics, stage, Hyams grade, dural infiltration status, and outcomes. Results: Three samples were excluded based on too little available tissue for meaningful analysis. Of the remaining 44, 38 were primary and 6 were recurrent tumors. PMNs, monocytes, and macrophages are present in the TIME of ONB at 22 cells per mm2, 2.0 cells per mm2, and 34 cells per mm2 respectively. Increased PMN and macrophage cell densities were noted in the stroma when compared to the tumor parenchyma (28 cells per mm2 vs 14 cells per mm2, p&amp;lt;0.0001 and 46 cells per mm2 vs 21 cells per mm2, p&amp;lt;0.0001). A similar trend was seen in monocytes (3.5 cells per mm2 vs 0.80 cells per mm2, p=0.0588) but it did not reach statistical significance. When we compared by Kadish Stage, higher stage (C/D) had more tumor infiltrating PMNs than low stage (A/B) (median of 1.3 cells per mm2 vs median 0 cells per mm2, p=0.0011). No further differences in cell distributions were noted when comparing for Hyams grade, stage, dural infiltration, recurrent disease, or other clinical factors. Nearest neighbor analysis demonstrates that macrophages are closer to tumor cells than PMNs or monocytes (19.68 µm vs 27.78 µm, p&amp;lt;0.0001, and 25.77 µm, p=0.0026, respectively). Conclusion: This study is the first to comprehensively define the ONB myeloid TIME using mxIF. Our study demonstrates the ONB TIME contains abundant myeloid populations. As these cells have been shown to be immunosuppressive, thereby fostering tumor cell escape and host evasion, in other human malignancies we posit they play a similar role in ONB. The functional study of myeloid populations in ONB, and whether they represent targets for therapeutic intervention, is warranted. Citation Format: Riley Larkin, Diana Lopez, Yvette Robbins, Wiem Lassoued, Gary Gallia, Clint T. Allen, Nyall R. London. Multispectral immunofluorescence analysis of the olfactory neuroblastoma tumor immune microenvironment reveals macrophage and polymorphonuclear leukocyte stroma localization and tumor parenchyma exclusion. [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 4706.

Abstract 4588: Vascular regulation of T-cell exclusion in melanoma

Abstract T-cell position in the tumor microenvironment determines the probability of target encounter and tumor killing. CD8+ T-cell exclusion from the tumor parenchyma is associated with poor response to immunotherapy and yet the biology that underpins this distinct pattern remains unclear. Here we show that the vascular destabilizing factor angiopoietin-2 (ANGPT2) causes compromised vascular integrity in the tumor periphery, leading to impaired T-cell infiltration within tumor. We analyzed the spatial regulation of ANGPT2 in whole tumor cross-sections and its impact on CD8+ T-cell position, vascular integrity, and response to immunotherapy using syngeneic murine melanomas. We found that T-cell exclusion was associated with peritumoral expression of ANGPT2 and elevated vascular leakage in human and murine melanomas. Both pharmacological and genetic blockade of ANGPT2 promoted CD8+ T-cell infiltration to the tumor core, exerting antitumor effects. Importantly, the reversal of T-cell exclusion following ANGPT2 blockade not only enhanced response to anti-PD-1 therapy in immunogenic, therapy responsive mouse melanomas, but also rendered non-responsive tumors susceptible. Therapeutic response after ANGPT2 blockade, driven by improved CD8+ T-cell infiltration, coincided with TIE2 signaling activation and increased vascular integrity in the tumor periphery, indicating that maintenance of vascular integrity within tumors is necessary for robust response to immunotherapy. These data highlight ANGPT2/TIE2 signaling as a key mediator of T-cell exclusion and a promising target to potentiate checkpoint inhibitor efficacy in melanoma. Citation Format: Ha-Ram Park, Anahita Shiva, Portia Cummings, Richard Carvajal, Gavin Thurston, Joon-Yong An, Amanda W. Lund, Hee Won Yang, Minah Kim. Vascular regulation of T-cell exclusion in melanoma. [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 4588.

Abstract 6631: Association between poliovirus receptor (PVR) expression in tumor and exclusion of immune cells expressing T cell immunoreceptor with Ig and ITIM domain (TIGIT) from tumor area

Abstract Context: TIGIT has grown to be an increasingly important target for immunotherapy of cancer. However, it is unclear if there is an association between abundance of TIGIT expressing immune cells in tumor microenvironment and effectiveness of TIGIT-based intervention. This study utilizes an exploratory novel duplex immunohistochemical (IHC) assay to assess if the distribution patterns and/or the abundance of TIGIT-positive immune cells are related to the expression levels of TIGIT’s receptor PVR in tumor. Methods: Individual formalin-fixed, paraffin-embedded surgical resections and tissue microarray cores of 75 cervical, 84 esophageal, 79 non-small cell lung , and 81 small cell lung carcinoma specimens were stained using a duplex chromogenic IHC assay that detects PVR and TIGIT sequentially on a single slide. The slides were examined for (1) overall intensity and percentage of tumor staining positive for PVR, (2) percentage of tumor area occupied by TIGIT-expressing immune cells, and (3) distribution pattern of TIGIT-positive cells. For each specimen, overall PVR intensity was multiplied by percentage of tumor positive for PVR to generate the PVR Expression Score. Results: PVR and TIGIT staining at any intensity was widely observed in all four tumor types ranging from 91% to 100% of specimens positive for PVR and 77% to 100% of specimens positive for TIGIT. Little to no differences in the average percentages of PVR tumor positivity or TIGIT tumor area positivity were found among the four tumor types. However, individual tumor specimens differed widely in these two parameters. Among all 319 tumor specimens evaluated, the percentages of tumor expressing PVR at any intensity ranged from 0 to 100% with approximately 1/3 of the specimens having less than 50% and 3% showing no PVR expression. Percentages of tumor area occupied by TIGIT-positive cells ranged from 0% to 30% with approximately 40% of the specimens having less than 1%. Distribution patterns of TIGIT-expressing cells in each specimen was classified as peritumoral, intratumoral, or mixed. Specimens classified as peritumoral exhibited higher PVR Expression Scores than those classified as intratumoral. Specimens classified as having a mixed TIGIT-positive cell distribution pattern had an average PVR Expression Score that was intermediate between specimens having intratumoral and peritumoral TIGIT distribution patterns. Interestingly, no correlation was found between tumor PVR Expression Scores and abundance of TIGIT expressing cells in tumor area. Conclusion: The correlation between high tumor PVR expression levels and peritumoral distribution patterns of TIGIT-positive cells suggests PVR/TIGIT signaling pathway activation status could be important in infiltration of T cells into tumor parenchyma. Citation Format: Sara A. Moore, Julie Cheung, Aram B. Cholanians, June Clements, Jessica L. Baumann, Tsu-Shuen Tsao. Association between poliovirus receptor (PVR) expression in tumor and exclusion of immune cells expressing T cell immunoreceptor with Ig and ITIM domain (TIGIT) from tumor area [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 6631.

Abstract 1255: Glucose dependent CD73+ CAFs enforce a tumor metabolic barrier that promotes T cell exclusion

Abstract Trafficking of T lymphocytes from the lymph nodes to the tumor microenvironment is a critical process of the tumor immunity cycle to elicit cytotoxic anti-tumor responses driven by CD8+ T cells. However, some tumors termed “immune excluded” recruit lymphocytes to the tumor site, but the lymphocytes are unable to penetrate the tumor parenchyma and localize primarily in the peritumoral region. In soft tissue sarcoma patients, most tumors are poorly infiltrated by T cells, which is associated with a poor response to immunotherapies. It has been described that cancer associated fibroblasts (CAFs) are enriched in immune excluded tumors and may directly block the migration of T cells via the production of dense extracellular matrix or by forging an immunosuppressive niche. We generated two models of undifferentiated pleomorphic sarcoma (UPS) that recapitulate the “immune excluded” and “inflamed” microenvironments observed in sarcoma patients. These syngeneic models rely on p53KO mesenchymal stem cells overexpressing either Ccne1 or Vgll3, which are frequently amplified in UPS patients. These models differ in their overall proportion of infiltrating TILs, and specifically T cells, making them ideal for comparative studies to investigate the mechanisms driving T cell exclusion in the TME. Using single-cell RNA-sequencing, we identified a population of CAFs expressing Nt5e, encoding CD73, which are spatially enriched in the peritumoral region of immune excluded Ccne1 tumors and closely associate with CD8+ T cells located at the tumor margin. Using transwell invasion assays, we show that CD73+ CAFs but not CD73- CAFs are able to block the migration of activated T cells towards tumor cells, even in the presence of CXCL10. Further, we show that Nt5e CAFs are enriched for signatures of glucose metabolism, and hypoxia, thus we hypothesized that CD73+ CAFs may block the migration of T cells into tumors by forging a nutrient poor metabolic barrier around the tumor. To test this, we treated Ccne1 tumors with BAY-876, a GLUT1 inhibitor and observed a significant accumulation of infiltrating CD8+ T cells compared to controls. GLUT1 treated CAFs expressed significantly less Nt5e, indicating that CD73 may play a role in the maintenance of glucose metabolism in CAFs. Furthermore, blockade of CD73 in CD73+ CAFs decreases the expression of the glucose transporter, Glut1. All together, these data suggest that CD73 may serve as a marker of glucose dependent CAFs that alter the metabolic niche to block T cell infiltration into tumors. Citation Format: Marina Broz, Emily Ko, Jinfen Xiao, Marco DeSimone, Roberta Piras, Kristin Ishaya, Xen Ping Hoi, Jlenia Guarnerio. Glucose dependent CD73+ CAFs enforce a tumor metabolic barrier that promotes T cell exclusion [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 1255.

DZIP1 expressed in fibroblasts and tumor cells may affect immunosuppression and metastatic potential in gastric cancer.

The tumor microenvironment (TME) contains complex components, of which the most well-known one is the tumor-associated fibroblast (CAF) that participates in the development and progression of tumors. A high abundance of CAFs implies that tumor stroma is also abundant and often predicts a poor prognosis, especially in terms of immunotherapeutic resistance. In this study, DAZ interacting zinc finger protein 1 (DZIP1) was identified to be upregulated in CAFs and malignant epithelial cells based on single-cell sequencing. Furthermore, results from The Cancer Genome Atlas database showed that this gene was highly positively associated with the mesenchymal phenotype in gastric cancer (GC). In addition, molecular experiments verified that DZIP1 directly promoted the proliferation of CAFs and enhanced the epithelial-mesenchymal transition (EMT) of GC cells to drive angiogenesis. Also, the upregulated DZIP1 in GC cells was found to directly promote invasion and metastasis. Finally, multiplex immunofluorescence and immunohistochemistry showed that DZIP1 was correlated with the immunosuppressive microenvironment of GC and resulted in a poor response to immunotherapy. Overall, our findings suggest that DZIP1 is expressed in both tumor parenchyma and mesenchyme and that it is involved in shaping the immunosuppressive microenvironment and inducing EMT by participating in tumor-stromal signaling crosstalk.

Clinicopathologic analysis of pineal parenchymal tumors of intermediate differentiation: a multi-institutional cohort study by the Kyushu Neuro-Oncology Study Group.

Pineal parenchymal tumors of intermediate differentiation (PPTIDs), which were recognized in the 2007 World Health Organization (WHO) classification, are rare, accounting for less than 1% of all central nervous system tumors. This rarity and novelty complicate the diagnosis and treatments of PPTID. We therefore aimed to evaluate the clinicopathological significance of this tumor. At 11 institutions participating in the Kyushu Neuro-Oncology Study Group, data for patients diagnosed with PPTID were collected. Central pathology review and KBTBD4 mutation analysis were applied to attain the diagnostically accurate cohort. PPTID was officially diagnosed in 28 patients: 11 (39%) with WHO grade 2 and 17 (61%) with WHO grade 3 tumors. Median age was 49years, and the male:female ratio was 1:2.1. Surgery was attempted in all 28 patients, and gross total resection (GTR) was achieved in 46% (13/28). Adjuvant radiotherapy and chemotherapy were administered to, respectively, 82% (23/28) and 46% (13/28). The 5-year progression-free survival (PFS) and overall survival rates were 64.9% and 70.4% respectively. Female sex (p = 0.018) and GTR (p < 0.01) were found to be independent prognostic factors for PFS and female sex (p = 0.019) was that for OS. Initial and second recurrences were most often leptomeningeal (67% and 100% respectively). 80% (20/25) of patients harbored a KBTBD4 mutation. Female sex and GTR were independent prognostic factors in our patients with PPTID. Leptomeningeal recurrence was observed to be particularly characteristic of this tumor. The rate of KBTBD4 mutation observed in our cohort was acceptable and this could prove the accuracy of our PPTID cohort.

Radiation therapy for pineal parenchymal tumor of intermediate differentiation: A case series and literature review.

Pineal parenchymal tumor of intermediate differentiation (PPTID) is a rare, primary tumor of the pineal gland. Due to its rarity, there is no consensus on optimal therapeutic strategies or standard characterization of the tumor's behavior. Here, we report 2 new cases of PPTID and an extensive review of the literature involving the use and extent of radiation therapy. Patient 1 is a 54-year-old male who presented with PPTID and drop metastases in the spinal cord, received cranial spinal irradiation (CSI), and experienced recurrence 3.5 years after treatment. Stereotactic body radiation therapy (SBRT) helped the patient into remission for 9months. Patient 2 is a 32-year-old male with a local PPTID at presentation who went on to receive surgical resection followed by focused adjuvant radiation therapy to the pineal tumor bed. He then presented 6years after treatment with extensive disseminated recurrence and died due to leptomeningeal disease (LMD) about 4years after recurrence. The available literature on PPTID is limited and reported cases of LMD with ongoing follow-up in PPTID are scarce. Our report adds to the current known PPTID cases, contributing to the information available regarding prognosis and treatment response. Although an optimal therapeutic strategy for PPTID still cannot be determined, data from the literature suggest that utilizing radiation therapy in patients with low-risk disease and gross total resections as well as the use of upfront CSI have the potential to improve patient progression and survival outcomes.