Tumor microenvironment and its clinicopathological and prognostic associations in surgically resected cutaneous angiosarcoma

Tumor Immune Microenvironment and Its Clinicopathological and Prognostic Associations in Canine Splenic Hemangiosarcoma

Tumor cells can induce important cellular and molecular modifications in the tissue or host where they grow. The idea that the host and tumor interact with each other has led to the concept of a tumor microenvironment, composed of immune cells, stromal cells, blood vessels, and extracellular matrix, representing a unique environment participating and, in some cases, promoting cancer progression. The study of the tumor immune microenvironment, particularly focusing on the role of tumor-infiltrating lymphocytes (TILs), is highly relevant in oncology due to the prognostic and therapeutic significance of TILs in various tumors and their identification as targets for therapeutic intervention. Canine splenic hemangiosarcoma (HSA) is a common tumor; however, its immune microenvironment remains poorly understood. This retrospective study aimed to characterize the histological and immunohistochemical features of 56 cases of canine splenic HSA, focusing particularly on tumor-infiltrating lymphocytes (TILs). We assessed the correlations between the lymphocytic response, the macroscopic and histological characteristics of the tumor, and the survival data. Our study demonstrated that FoxP3 distribution was associated with tumor-related death and survival, while the CD20 count was associated with metastasis. This study provides an in-depth characterization of the tumor immune microenvironment in canine splenic HSA and describes potential prognostic factors.

Tumor-Infiltrating Mast Cells in Angiosarcoma Correlate With Immuno-Oncology Pathways and Adverse Clinical Outcomes

Recent studies have described several molecular subtypes and deregulation of immuno-oncologic signaling pathways in angiosarcoma. Interestingly, mast cells were enriched in subsets of angiosarcoma, although their significance remains unknown. In this study, we aim to verify this observation using immunohistochemistry (H scores) and NanoString transcriptomic profiling and explore the association between mast cells with clinical and biological features. In the study cohort (N = 60), H scores showed a significant moderate correlation with NanoString mast cell scores (r = 0.525; P < .001). Both H score and NanoString mast cell scores showed a significant positive correlation (P < .05) with head and neck location, nonepithelioid morphology, and lower tumor grade. Mast cell enrichment significantly correlated with higher NanoString regulatory T-cell scores (H score, r = 0.32; P = .01; NanoString mast cell score, r = 0.27; P = .04). NanoString mast cell scores positively correlated with signaling pathways relating to antigen presentation (r = 0.264; P = .0414) and negatively correlated with apoptosis (r = -0.366; P = .0040), DNA damage repair (r = -0.348; P = .0064), and cell proliferation (r = -0.542; P < .001). Interestingly, in the metastatic setting, patients with mast cell-enriched angiosarcoma showed poorer progression-free survival (median, 0.2 vs 0.4 years; hazard ratio = 3.05; P = .0489) along with a trend toward worse overall survival (median, 0.2 vs 0.6 years; hazard ratio, 2.86; P = .0574) compared with patients with mast cell-poor angiosarcoma. In conclusion, we demonstrated the presence of mast cells in human angiosarcoma and provided initial evidence of their potential clinical and biological significance. Future research will be required to elucidate their specific roles and mechanisms, which may uncover novel avenues for therapeutic intervention.

PD-L1 Expression in Cutaneous Angiosarcomas: A Systematic Review with Meta-Analysis

Cutaneous angiosarcoma (CAS) is the most common type of angiosarcoma that predominantly affects older Caucasians. The outcomes of immunotherapy in CAS are currently under investigation in relation to the expression of programmed death ligand 1 (PD-L1) and other biomarkers. We performed a systematic review and metanalysis of data from the current literature reporting on PD-L1 immunohistochemistry expression. A systematic search of publications in the electronic databases PubMed, Web of Science, and Scopus was conducted using the following terms: "PD-L1" and "angiosarcomas". A total of ten studies reporting on 279 cases were identified and included in the meta-analysis. The pooled prevalence of PD-L1 expression in CAS was 54% (95% CI 36-71%), with high heterogeneity (I² = 84.81%, p < 0.001). In sub-group analysis, the proportion of PD-L1 expression in CAS was significantly (p = 0.049) lower in Asian studies (ES = 35%, 95% CI 28-42%, I² = 0.0%, p = 0.46) than in European studies (ES = 71%, 95% CI 51-89%, I² = 48.91%, p = 0.12).