Molecular and immune pathobiology of human angiosarcoma.

Angiosarcoma is a rare endothelial-derived malignancy that is extremely diverse in anatomy, aetiology, molecular and immune characteristics. While novel therapeutic approaches incorporating targeted agents and immunotherapy have yielded significant improvements in patient outcomes across several cancers, their impact on angiosarcoma remains modest. Contributed by its heterogeneous nature, there is currently a lack of novel drug targets in this disease entity and no reliable biomarkers that predict response to conventional treatment. This review aims to examine the molecular and immune landscape of angiosarcoma in association with its aetiology, anatomical sites, prognosis and therapeutic options. We summarise current efforts to characterise angiosarcoma subtypes based on molecular and immune profiling. Finally, we highlight promising technologies such as single-cell spatial "omics" that may further our understanding of angiosarcoma and propose strategies that can be similarly applied for the study of other rare cancers.

Hemangiosarcoma cells induce M2 polarization and PD-L1 expression in macrophages.

Hemangiosarcoma (HSA) is a malignant tumor derived from endothelial cells. Tumor-associated macrophages are one of the major components of tumor microenvironment and crucial for cancer development. The presence and function of macrophages in HSA have not been studied because there is no syngeneic model for HSA. In this study, we evaluated two mouse HSA cell lines and one immortalized mouse endothelial cell line for their usefulness as syngeneic models for canine HSA. Our results showed that the ISOS-1 cell line developed tumors with similar morphology to canine HSA. ISOS-1 cells highly expressed KDM2B and had similar KDM2B target expression patterns with canine HSA. Moreover, we determined that in both ISOS-1 and canine HSA tumors, macrophages were present as a major constituent of the tumor microenvironment. These macrophages were positive for CD204, an M2 macrophage marker, and express PD-L1, an immune checkpoint molecule. Canine HSA with macrophages expressing PD-L1 had a smaller number of T-cells in tumor tissues than tumors with PD-L1 negative macrophages. ISOS-1-conditioned medium could induce M2 polarization and PD-L1 expression in RAW264.7 mouse macrophage cell line and mouse peritoneal macrophages. These results show that ISOS-1 can be used as a syngenic model for canine HSA and suggest that macrophages play an important role in immune evasion in HSA. Using the syngeneic mouse model for canine HSA, we can further study the role of immune cells in the pathology of HSA.

Multiomic analysis and immunoprofiling reveal distinct subtypes of human angiosarcoma.

Angiosarcomas are rare, clinically aggressive tumors with limited treatment options and a dismal prognosis. We analyzed angiosarcomas from 68 patients, integrating information from multiomic sequencing, NanoString immuno-oncology profiling, and multiplex immunohistochemistry and immunofluorescence for tumor-infiltrating immune cells. Through whole-genome sequencing (n = 18), 50% of the cutaneous head and neck angiosarcomas exhibited higher tumor mutation burden (TMB) and UV mutational signatures; others were mutationally quiet and non-UV driven. NanoString profiling revealed 3 distinct patient clusters represented by lack (clusters 1 and 2) or enrichment (cluster 3) of immune-related signaling and immune cells. Neutrophils (CD15+), macrophages (CD68+), cytotoxic T cells (CD8+), Tregs (FOXP3+), and PD-L1+ cells were enriched in cluster 3 relative to clusters 2 and 1. Likewise, tumor inflammation signature (TIS) scores were highest in cluster 3 (7.54 vs. 6.71 vs. 5.75, respectively; P < 0.0001). Head and neck angiosarcomas were predominant in clusters 1 and 3, providing the rationale for checkpoint immunotherapy, especially in the latter subgroup with both high TMB and TIS scores. Cluster 2 was enriched for secondary angiosarcomas and exhibited higher expression of DNMT1, BRD3/4, MYC, HRAS, and PDGFRB, in keeping with the upregulation of epigenetic and oncogenic signaling pathways amenable to targeted therapies. Molecular and immunological dissection of angiosarcomas may provide insights into opportunities for precision medicine.

Angiosarcoma heterogeneity and potential therapeutic vulnerability to immune checkpoint blockade: insights from genomic sequencing.

BACKGROUND: Angiosarcoma is an aggressive tumor. Recent case series describe exceptional responses to checkpoint blockade in this disease. METHODS: Herein, we explored the genomic correlates of 48 angiosarcomas from the Angiosarcoma Project (12,499 variants analyzed in 6603 genes; whole-exome sequencing) versus 10,106 pan-cancer tumors in The Cancer Genome Atlas including 235 sarcomas but no angiosarcoma. RESULTS: At the molecular level, angiosarcomas were heterogeneous. Those located in the face and scalp presented high tumor mutation burden, missense amino acid variations biased towards more hydrophobic (and therefore more immunogenic) peptides, and ultra-violet mutational signature. CONCLUSIONS: Angiosarcoma molecular features are similar to those observed in melanoma and other skin tumors and may explain comparable immunotherapy sensitivity of these tumor types.

Arteriovenous graft in kidney transplant patients: Lookout for the rare but fearsome angiosarcoma.

INTRODUCTION: Angiosarcomas are rare tumors, comprising less than 1% of all sarcomas. However, they portend a poor prognosis, as they tend to metastasize early, being of uttermost importance a prompt diagnosis and treatment. CASE DESCRIPTION: We present the case of a 55-year-old female with history of kidney transplantation, immunosuppressed with tacrolimus, prednisolone, and mofetil mycophenolate. Fifteen years after the transplant, she developed an ulcerated lesion on the site of a nonfunctioning arteriovenous graft, which was excised. Histology was compatible with a high grade angiosarcoma that invaded the margins, and immunosuppression was switched to everolimus. Staging imaging exams revealed lymph node, muscle, and lung metastases. Shortly after, nodular lesions appeared compatible with local recurrence of the disease, and the patient showed severe deterioration of her clinical condition, being proposed for palliative chemotherapy. However, the disease showed an explosive progression and the patient died before starting the treatment. CONCLUSION: This case emphasizes the importance of including inspection of the vascular access (functioning or not) in regular post-transplant consultation and value any alterations in the attempt of a timely diagnosis. Although rare, angiosarcoma is an important entity that should be considered in the differential diagnosis of soft tissue masses arising from a vascular access, especially in immunocompromised patients. Aggressive treatment should be offered whenever possible.

Fat-associated lymphoid cluster in Cyprinus carpio: Characterisation and its relation with peritoneal haemangiosarcoma.

FALC cells are natural helper cells producing Th2-type cytokines, which express c-kit, Sca-1, IL7R and CD45 in mouse and human. These cells are involved in allergic responses and contribute to the inflammatory reactions of adipose tissue; however, a lack of information prevails about the presence of these cells in other species. The aim of the study was to identify and characterise FALC cells in the common carp (Cyprinus carpio) using immunohistochemistry and molecular biology techniques as well as to explore their relationships with their microenvironment. Histological description of the FALC was performed using H&E and polyclonal antibodies were used against cell-surface markers such as c-kit, Sca-1 and CD45. Furthermore, gene expression of c-kit, Sca-1 and IL7R was assessed. C. carpio FALC cells express the same surface markers reported in FALC of the mouse at both the pre- and post-transcriptional level. By exposure to the soluble fraction of helminths, FALC cells produce abundant Th2 cytokines (IL-5, IL-6 and IL-13) but do not synthesise IL-1α. Additionally, FALC cells probably participate in vascular remodelling of the intestine vessels, inducing tumours because a malignant haemangiosarcoma in the peritoneal cavity was found. In this tumour, abundant FALC with their characteristic cell-surface markers were detected. The findings of this study suggest the involvement of some proto-oncogenes such as c-kit and Sca-1, and the deregulation of Src kinases modulated by CD45 present in C. carpio FALC with the ontogeny of peritoneal haemangiosarcoma in this fish species.

Genome-wide association study identifies shared risk loci common to two malignancies in golden retrievers.

Dogs, with their breed-determined limited genetic background, are great models of human disease including cancer. Canine B-cell lymphoma and hemangiosarcoma are both malignancies of the hematologic system that are clinically and histologically similar to human B-cell non-Hodgkin lymphoma and angiosarcoma, respectively. Golden retrievers in the US show significantly elevated lifetime risk for both B-cell lymphoma (6%) and hemangiosarcoma (20%). We conducted genome-wide association studies for hemangiosarcoma and B-cell lymphoma, identifying two shared predisposing loci. The two associated loci are located on chromosome 5, and together contribute ~20% of the risk of developing these cancers. Genome-wide p-values for the top SNP of each locus are 4.6×10-7 and 2.7×10-6, respectively. Whole genome resequencing of nine cases and controls followed by genotyping and detailed analysis identified three shared and one B-cell lymphoma specific risk haplotypes within the two loci, but no coding changes were associated with the risk haplotypes. Gene expression analysis of B-cell lymphoma tumors revealed that carrying the risk haplotypes at the first locus is associated with down-regulation of several nearby genes including the proximal gene TRPC6, a transient receptor Ca2+-channel involved in T-cell activation, among other functions. The shared risk haplotype in the second locus overlaps the vesicle transport and release gene STX8. Carrying the shared risk haplotype is associated with gene expression changes of 100 genes enriched for pathways involved in immune cell activation. Thus, the predisposing germ-line mutations in B-cell lymphoma and hemangiosarcoma appear to be regulatory, and affect pathways involved in T-cell mediated immune response in the tumor. This suggests that the interaction between the immune system and malignant cells plays a common role in the tumorigenesis of these relatively different cancers.

Lymphedema-related angiogenic tumors and other malignancies.

Chronic lymphedema has a permissive effect with certain types of malignancies, particularly angiosarcomas, in what is known as Stewart-Treves syndrome. The presumed mechanism of this effect is an immunocompromised district of the affected area. Most other cutaneous malignancies have also been described in lymphedematous areas, including basal cell carcinoma, squamous cell carcinoma, melanoma, Kaposi sarcoma, Merkel cell carcinoma, and several cutaneous lymphomas. The occurrence of such malignancies suggests a more general immunosuppression within the skin. The formation of collateral lymphatic and vascular vessels in response to lymphedema produces an environment rich in growth factors, which may also play a role. In addition to infection and other general skin care issues, regions affected by lymphedema should be monitored for malignant changes not limited to angiosarcomas.

CD8⁺ tumor-infiltrating lymphocytes at primary sites as a possible prognostic factor of cutaneous angiosarcoma.

Tumor-infiltrating lymphocytes (TILs) have been reported as a prognostic factor in various cancers and are a promising target for immunotherapy. To investigate whether TILs have any impact on the prognosis of angiosarcoma patients, 55 non-treated patients (40 patients at stage 1 with cutaneous localized tumors, 4 patients at stage 2 with lymph node metastases and 11 patients at stage 3 with distant metastases) with angiosarcoma were evaluated retrospectively by immunohistochemistry stained CD4, CD8, FOXP3 and Ki67. The Kaplan-Meier method was used to estimate overall survival with patients at stage 1. Survival differences were analyzed by the log-rank test. Patients with higher numbers of CD8(+) TILs in their primary tumors survived significantly longer compared with patients with lower values. Moreover, the number of CD8 in TILs was positively correlated with a distant metastasis-free period. The total number of primary TILs (CD4 plus CD8) and CD8(+) primary TILs of stage 3 patients with distant metastases was positively correlated with their overall survival. To evaluate whether CD8(+) effector T cells are activated or differentiated, flow cytometric analysis of peripheral blood mononuclear cells (PBMC) was performed. The percentages of CD8(+) T cells producing IFN-γ in PBMC were significantly higher in patients with angiosarcoma (n = 10) compared not only with that of healthy controls (n = 20) but also patients with advanced melanoma (n = 11). These results suggest that anti-tumor immunity is clinically relevant in angiosarcoma.

Anti-tumor effects of inactivated Sendai virus particles with an IL-2 gene on angiosarcoma.

Cutaneous angiosarcoma is a life-threatening tumor that is resistant to conventional therapies. The therapeutic effects of Sendai virus particles (hemagglutinating virus of Japan envelope: HVJ-E) carrying IL-2 gene (HVJ-E/IL-2) were examined in a mouse model of angiosarcoma. Intra-tumoral injection of HVJ-E/IL-2 effectively inhibited the growth of angiosarcoma cells (ISOS-1) inoculated in mice and improved tumor-free rates. HVJ-E/IL-2 stimulated local accumulation of CD8 (+) T cells and NK cells and reduced regulatory T cells in regional lymph nodes. Notably, the prevalence of myeloid-derived suppressor cells was lower in HVJ-E/IL-2-treated mice than in HVJ-E-treated mice. HVJ-E/IL-2 treatment promoted IFN-γ production from CD8 (+) T cells in response to tumor cells, more significantly than HVJ-E treatment. Greatly improved tumor-free rates were obtained when sunitinib, a tyrosine kinase inhibitor, was administered in combination with HVJ-E/IL-2. Immunogene therapy with HVJ-E/IL-2 with or without sunitinib could be a promising therapeutic option for cutaneous angiosarcoma.

Comparison of immunosuppressive and cytotoxic cells in angiosarcoma: development of a possible supportive therapy for angiosarcoma.

An imbalance of immunosuppressive and cytotoxic cells plays an important role in inhibiting the anti-tumor immune response of the tumor-bearing host. The purpose of this study was to elucidate the involvement of immunosuppressive cells, such as regulatory T cells and CD163+ M2 macrophages as well as cytotoxic cells, such as granulysin-bearing cells and TIA-1+ cells in cutaneous angiosarcoma (AS) by immunohistochemical staining. In addition we evaluated the potencies of bisphosphonate, which was previously reported to suppress the expression of matrix metalloproteinase 9 (MMP-9), as a supportive therapy for AS together with docetaxel in 6 cases of cutaneous AS. These findings suggest that a high number of immunosuppressive cells might be related to the prognosis of AS, and that a combination of docetaxel with bisphosphonate risedronate sodium might be effective for MMP-9-expressing AS.

Immunomodulatory effect of bisphosphonate risedronate sodium on CD163+ arginase 1+ M2 macrophages: the development of a possible supportive therapy for angiosarcoma.

An imbalance of immunosuppressive cells and cytotoxic cells plays an important role in inhibiting the antitumor immune response of the tumor-bearing host. We previously reported the profiles of tumor infiltrating leukocytes in cutaneous angiosarcoma (AS) and suggested that a combination of docetaxel (DTX) with bisphosphonate risedronate sodium (RS) might be effective for MMP9-expressing AS by targeting immunosuppressive cells such as M2 macrophages. To further confirm the effect of this combination therapy, in this report we investigated the immunomodulatory effect of DTX and RS on CD163(+) arginase 1 (Arg1)(+) M2 macrophages in vitro. Interestingly, our present study demonstrated that DTX in combination with RS significantly upregulated the mRNA expression of CXCL10 on M2 macrophages and significantly decreased the mRNA expression of CCL17 and Arg1. Moreover, the production of CXCL10 and CXCL11 from M2 macrophages was significantly increased by DTX with RS though there was no effect of DTX with RS on the production of CCL5 and CCL17. Furthermore, DTX with RS significantly decreased the production of CCL18, which was previously reported to correlate with the severity and prognosis in cancer patients. Our present report suggests one of the possible mechanisms of DTX with RS in the supportive therapy for angiosarcoma.

Evaluation of expression profiles of hematopoietic stem cell, endothelial cell, and myeloid cell antigens in spontaneous and chemically induced hemangiosarcomas and hemangiomas in mice.

It is unclear whether the process of spontaneous and chemically induced hemangiosarcoma and hemangioma formation in mice involves the transformation of differentiated endothelial cells (ECs) or recruitment of multipotential bone marrow-derived hematopoietic stem cells or endothelial progenitor cells (EPCs), which show some degree of endothelial differentiation. In the present study, immunohistochemical staining for hematopoietic stem cell markers (CD45 and CD34), EC markers (vascular endothelial growth factor receptor 2 [VEGFR2], CD31, and factor VIII-related antigen), and a myeloid lineage marker (CD14) was employed to better define the origin of hemangiosarcomas and hemangiomas in mice. Staining was negative for CD45, factor VIII-related antigen, and CD14 and positive for CD34, VEGFR2, and CD31, indicating that mouse hemangiosarcomas and hemangiomas are composed of cells derived from EPCs expressing CD34, VEGFR2, and CD31 but not factor VIII-related antigen. The lack of CD45 expression suggests that mouse vascular tumors may arise from EPCs that are at a stage later than hematopoietic stem cells. Since factor VIII-related antigen expression is known to occur later than CD31 expression in EPCs, our observations may indicate that these tumor cells are arrested at a stage prior to complete differentiation.  In addition, myeloid lineage cells do not appear to contribute to hemangiosarcoma and hemangioma formation in mice.

Sarcomas other than Kaposi sarcoma occurring in immunodeficiency: interpretations from a systematic literature review.

PURPOSE OF REVIEW: In immunodeficiency, an increased sarcoma risk is confirmed for Kaposi's sarcoma. Whether rates of other sarcoma subtypes are elevated in the setting of immunodeficiency is not known. We therefore reviewed published case reports on HIV and AIDS patients and organ transplant recipients with sarcomas. For comparison, we assessed sarcomas in the U.S. general population using Surveillance Epidemiology End Results (SEER) data. RECENT FINDINGS: A total of 176 non-Kaposi sarcoma were identified, 75 in people with HIV and AIDS and 101 in transplant recipients. Leiomyosarcomas (n = 101) were the most frequently reported sarcomas, followed by angiosarcomas (n = 23) and fibrohistiocytic tumors (n = 17). Leiomyosarcomas were reported with two age peaks, in children and young adults. Epstein-Barr virus (EBV) was detected in the tumor cells in 85 and 88% of leiomyosarcomas in HIV-infected people and transplant recipients, respectively. Angiosarcomas and fibrohistiocytic tumors were most frequently reported in men. Among kidney transplant recipients, 20% of sarcomas arose at the site of an arteriovenous fistula. In comparison, leiomyoscarcomas, angiosarcomas, and fibrohistiocytic tumors comprised 16.9, 3.8, and 18.7% of sarcomas in the U.S. general population. SUMMARY: Leiomyosarcoma and angiosarcoma may occur disproportionately in immunodeficiency. Leiomyosarcomas appear causatively linked to EBV, whereas angiosarcomas might be correlated with an arteriovenous fistula. Additional studies are necessary to understand the contribution of immunodeficiency to the cause of these sarcomas.

Establishment and characterization of a novel lymphangiosarcoma cell line (MO-LAS) compared with the hemangiosarcoma cell line (ISO-HAS).

The concept of "lymphangiosarcoma" remains obscure. Therefore, we reported a patient with lymphangiosarcoma, resistant to immunotherapy. The patient presented with impressive and discriminative features: clinically an ill-defined edematous lesion with lymphorrhea and pathologically atypical vascular channel formation without extravasation of blood, clearly distinguished from common angiosarcoma with hemorrhage. From this case, a lymphangiosarcoma cell line, MO-LAS, was established and its characteristics were compared with the hemangiosarcoma cell line, ISO-HAS. Flow cytometric analysis revealed that MO-LAS was negative for factor VIII-related antigen, but positive for CD31, D2-40, NZ-1, and vascular endothelial growth factor receptor-3 (VEGFR-3), similar to ISO-HAS. However, MO-LAS expressed a much higher level of homeobox gene PROX1, indicating a lymphatic phenotype, compared with ISO-HAS. Furthermore, MO-LAS showed a much lesser expression of oncogenes and much lower sensitivity against lymphokine-activated killer (LAK) cells. Lymphangiosarcoma may be difficult to recognize by the immune system. Conclusively, the establishment of MO-LAS, a novel angiosarcoma cell line bearing lymphatic characters, strongly suggests the entity of lymphangiosarcoma.