Which angiosarcoma subtypes may benefit from immunotherapy?

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Background: Angiosarcomas (AS) are aggressive mesenchymal tumors arising from cells with endothelial properties. They include de novo primary AS (pAS), and secondary AS (sAS) due to prior radiotherapy, UV exposure or chronic lymphedema. Treatment options are limited and their prognosis is poor. Development of new treatment strategies is difficult due to the heterogeneity and rarity of AS. We hypothesize that immunological and genomic profiles are significantly different between pAS and sAS and may result in different immune checkpoint inhibition (ICI) based treatment strategies. Methods: Tumor samples from AS patients were retrospectively collected. Patients were categorized as pAS or sAS. Lymphocytes were analyzed using multiplex immunohistochemistry on tissue microarrays. Genomic profiling was performed in a selected subgroup with “TruSight Oncology 500”, a Next Generation Sequencing panel containing 523 cancer related genes. Results: Immunological data were analyzed from 257 AS patients. The cohort comprised 80 pAS patients and 177 sAS patients. The median density of CD3+ T cells was 250 cells/mm2 in pAS vs 452 cells/mm2 in sAS (p< 0.001). Median CD4+ T helper cell density was 128 cells/mm2 in pAS vs 246 cells/mm2 in secondary AS (p< 0.001). The median density of CD8+ cytotoxic T cells was 85 cells/mm2 in pAS vs 111 cells/mm2 in sAS ( p= 0.057). Density of FoxP3+ T regulatory cells was higher in sAS (median 42 cells/mm2) compared to pAS (median 23 cells/mm2) (p< 0.001). The median count of CD20+ B cells in pAS was 24 cells/mm2 compared to 32 cells/mm2 in sAS ( p= 0.533). Genomic analysis was performed on tumor DNA from 51 patients (25 pAS and 26 sAS). Median tumor mutational burden (TMB) was 3.2 (range 0.8-11.9) mutations per megabase (mut/Mb) in pAS vs 3.9 (range 0.0-99.6) in sAS ( p= 0.485). No microsatellite instability was detected. A pathogenic mutation, gene amplification or gene loss was identified in 82% of all patients (n = 42, 70% of pAS vs 100% of sAS ( p< 0.01)). In 36 patients (71%) at least one (likely) pathogenic mutation was detected (54% pAS vs 88% sAS, ( p= 0.013)). In 20 patients (39%) mutations in the DNA damage response (DDR) pathway were detected (12% pAS vs 68% sAS ( p< 0.01)). The most frequently found mutated genes were TP53 (10%), BRAF (6%), ERCC4 (6%), PTPRD (6%), WETD2 (6%) and SETD2 (6%). Amplifications were found in 49% (n = 25) of all patients (15% pAS vs 84% sAS, ( p< 0,01)). MYC amplifications were most common and were detected in 15% of pAS and 68% of sAS. Immune profiles of the 51 genomically characterized patients are currently under further investigation. Conclusions: We showed a clear distinction in immunological and genomic profiles between pAS and sAS. The potential benefit of ICI seems to be most promising in sAS with a T cell inflamed tumor microenvironment, frequent MYC amplifications, DDR mutations, and high mutational load, while in pAS boosting strategies to enhance susceptibility to ICI might be interesting for further investigation.

Trends in Treatment and Survival of Gallbladder Cancer in the Netherlands; Identifying Gaps and Opportunities from a Nation-Wide Cohort

Gallbladder cancer (GBC) is rare in Western populations and data about treatment and outcomes are scarce. This study aims to analyze survival and identify opportunities for improvement using population-based data from a low-incidence country. GBC patients diagnosed between 2005 and 2016 with GBC were identified from the Netherlands Cancer Registry. Patients were grouped according to time period (2005–2009/2010–2016) and disease stage. Trends in treatment and overall survival (OS) were analyzed. In total 1834 patients were included: 661 (36%) patients with resected, 278 (15%) with non-resected non-metastatic, and 895 (49%) with metastatic GBC. Use of radical versus simple cholecystectomy (12% vs. 26%, p < 0.001) in early (pT1b/T2) GBC increased. More patients with metastatic GBC received chemotherapy (11% vs. 29%, p < 0.001). OS improved from 4.8 months (2005–2009) to 6.1 months (2010–2016) (p = 0.012). Median OS increased over time (2005–2009 vs. 2010–2016) in resected (19.4 to 26.8 months, p = 0.038) and metastatic (2.3 vs. 3.4 months, p = 0.001) GBC but not in unresected, non-metastatic GBC. In early GBC, patients with radical cholecystectomy had a median OS of 76.7 compared to 18.4 months for simple cholecystectomy (p < 0.001). Palliative chemotherapy showed superior (p < 0.001) survival in metastatic (7.3 versus 2.1 months) and non-resected non-metastatic (7.7 versus 3.5 months) GBC. In conclusion, survival of GBC remains poor. Radical surgery and palliative chemotherapy appear to improve prognosis but remain under-utilized.

Molecular Profiling of Druggable Targets in Clear Cell Renal Cell Carcinoma Through Targeted RNA Sequencing

Clear cell renal cell carcinoma (ccRCC) comprises more than 80% of all renal cancers and when metastasized leads to a 5-year survival rate of only 10%. The high rate of therapy failure and resistance development calls for reliable methods that provide information on the actionable biological pathways and predict optimal treatment protocols for individual patients. We here applied targeted RNA sequencing (t/RNA-NGS) using single molecule Molecular Inversion Probes on tumor nephrectomy samples of five ccRCC patients, comparing tumor with healthy kidney tissues. Transcriptome profiling focused on expression of genes with involvement in ccRCC biology that can be targeted with clinically available drugs. Results confirm high expression of vascular endothelial growth factor-A (VEGF-A) in tumor tissue relative to healthy-appearing kidney, in line with the angiogenic nature of ccRCC. PDGFRα and KIT, targets of the multi-kinase inhibitor sunitinib which is one of the current choices of first-line drug in metastasized ccRCC patients, were expressed at relatively low levels in tumor tissues, whereas significantly increased in normal kidney. Of all measured druggable tyrosine kinases, MET, AXL, or EGFR were expressed at higher levels in tumors than in normal kidney tissues, although intertumor differences were observed. Using cancer cell lines we show that t/RNA-NGS gene expression profiles can be used to predict in vitro sensitivity to targeted drugs. In conclusion, t/RNA-NGS analysis may provide insights into the (druggable) molecular make-up of individual renal cancers, and may guide personalized therapy of renal cell cancers.

Isocitrate dehydrogenase 1-mutated human gliomas depend on lactate and glutamate to alleviate metabolic stress

Diffuse gliomas often carry point mutations in isocitrate dehydrogenase ( IDH1^mut), resulting in metabolic stress. Although IDH^mut gliomas are difficult to culture in vitro, they thrive in the brain via diffuse infiltration, suggesting brain-specific tumor-stroma interactions that can compensate for IDH-1 deficits. To elucidate the metabolic adjustments in clinical IDH^mut gliomas that contribute to their malignancy, we applied a recently developed method of targeted quantitative RNA next-generation sequencing to 66 clinical gliomas and relevant orthotopic glioma xenografts, with and without the endogenous IDH-1^R132H mutation. Datasets were analyzed in R using Manhattan plots to calculate distance between expression profiles, Ward's method to perform unsupervised agglomerative clustering, and the Mann Whitney U test and Fisher's exact tests for supervised group analyses. The significance of transcriptome data was investigated by protein analysis, in situ enzymatic activity mapping, and in vivo magnetic resonance spectroscopy of orthotopic IDH1^mut- and IDH^wt-glioma xenografts. Gene set enrichment analyses of clinical IDH1^mut gliomas strongly suggest a role for catabolism of lactate and the neurotransmitter glutamate, whereas, in IDH^wt gliomas, processing of glucose and glutamine are the predominant metabolic pathways. Further evidence of the differential metabolic activity in these cancers comes from in situ enzymatic mapping studies and preclinical in vivo magnetic resonance spectroscopy imaging. Our data support an evolutionary model in which IDH^mut glioma cells exist in symbiosis with supportive neuronal cells and astrocytes as suppliers of glutamate and lactate, possibly explaining the diffuse nature of these cancers. The dependency on glutamate and lactate opens the way for novel approaches in the treatment of IDH^mut gliomas.-Lenting, K., Khurshed, M., Peeters, T. H., van den Heuvel, C. N. A. M., van Lith, S. A. M., de Bitter, T., Hendriks, W., Span, P. N., Molenaar, R. J., Botman, D., Verrijp, K., Heerschap, A., ter Laan, M., Kusters, B., van Ewijk, A., Huynen, M. A., van Noorden, C. J. F., Leenders, W. P. J. Isocitrate dehydrogenase 1-mutated human gliomas depend on lactate and glutamate to alleviate metabolic stress.

Selective MET Kinase Inhibition in MET-Dependent Glioma Models Alters Gene Expression and Induces Tumor Plasticity

The receptor tyrosine kinase (RTK) MET represents a promising tumor target in a subset of glioblastomas. Most RTK inhibitors available in the clinic today, including those inhibiting MET, affect multiple targets simultaneously. Previously, it was demonstrated that treatment with cabozantinib (MET/VEGFR2/RET inhibitor) prolonged survival of mice carrying orthotopic patient-derived xenografts (PDX) of the MET-addicted glioblastoma model E98, yet did not prevent development of recurrent and cabozantinib-resistant tumors. To exclude VEGFR2 inhibition-inflicted blood-brain barrier normalization and diminished tumor distribution of the drug, we have now investigated the effects of the novel MET-selective inhibitor Compound A in the orthotopic E98 xenograft model. In vitro, Compound A proved a highly potent inhibitor of proliferation of MET-addicted cell lines. In line with its target selectivity, Compound A did not restore the leaky blood-brain barrier and was more effective than cabozantinib in inhibiting MET phosphorylation in vivo Compound A treatment significantly prolonged survival of mice carrying E98 tumor xenografts, but did not prevent eventual progression. Contrasting in vitro results, the Compound A-treated xenografts displayed high levels of AKT phosphorylation despite the absence of phosphorylated MET. Profiling by RNA sequencing showed that in vivo transcriptomes differed significantly from those in control xenografts.Implications: Collectively, these findings demonstrate the plasticity of paracrine growth factor receptor signaling in vivo and urge for prudency with in vitro drug-testing strategies to validate monotherapies. Mol Cancer Res; 15(11); 1587-97. ©2017 AACR.