Prognostic implications of PD-L1 expression in patients with angiosarcoma

Propranolol monotherapy in angiosarcoma - A window-of-opportunity study (PropAngio)

BACKGROUND

Angiosarcoma is a rare and aggressive cancer of the endothelial cells. Propranolol, a non-selective β-blocker, was able to initiate apoptosis in angiosarcoma cell lines and its anti-tumor activity has been described in several case reports. The aim of this trial was to prospectively evaluate the anti-tumor activity of propranolol monotherapy in patients with angiosarcoma before proceeding to standard of care treatment.

METHODS

Propranolol was dosed 80 mg to 240 mg/day for 3 to 6 weeks according to a dose titration schedule. The primary endpoint was clinical response (response according to RECIST 1.1 or stable disease with improvement of cutaneous lesions) in at least three patients. Exploratory objectives included histologic response (>30% decrease in Ki-67), FDG PET response, and β-receptor expression levels.

RESULTS

Fourteen patients were enrolled. The median duration of treatment was 26 days (range 21-42 days). The median highest propranolol dose was 160 mg/day (range 80 - 240 mg). Two patients showed clinical response (14%, 95% CI 3-100%). One of these patients showed a partial metabolic response on PET-CT. None of the tumors showed histologic response. The most common adverse event was grade 1/2 bradycardia (86%). There were no grade ≥ 3 adverse events. ADRB2 was overexpressed in 16 out of 18 tumors, in both responders and non-responders. None of the tumors showed ADRB1 overexpression.

CONCLUSIONS

This window-of-opportunity trial did not show clinical efficacy of propranolol monotherapy. However, two out of 14 patients did show clinical benefit. ADRB1/2 expression did not correlate with clinical response.

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).

Analysis of PD-1, PD-L1, and T-cell infiltration in angiosarcoma pathogenetic subgroups

Angiosarcoma (AS) is a rare malignancy with a poor prognosis. It can develop spontaneously or due to previous radiotherapy (RT), ultraviolet (UV) radiation, or lymphoedema (Stewart Treves AS). Novel therapeutic approaches are needed, but progress is hindered because of the heterogeneity and rarity of AS. In order to explore the potential of immune checkpoint inhibition (ICI), we investigated the protein expression of programmed cell death 1 (PD-1), programmed death-ligand 1 (PD-L1), and CD8 + T cells in 165 AS cases in relation to AS subgroups based on clinical classification and in relation to whole-genome methylation profiling based clusters (A1, A2, B1, B2). High PD-L1 and PD-1 expression were predominantly shown in UV-associated, visceral, and soft tissue AS. RT-associated AS showed predominantly high PD-1 expression. CD8 + T cell infiltration was present in the majority of AS samples. Within the UV-associated AS, two different clusters can be distinguished by DNA methylation profiling. Cases in cluster A1 showed higher PD-1 (p = 0.015), PD-L1 (p = 0.015), and CD8 + T cells (p = 0.008) compared to those in cluster B2, suggesting that these UV-AS tumors are more immunogenic than B2 tumors showing a difference even within one subgroup. In soft tissue AS, combined PD-1 and PD-L1 expression showed a trend toward poor survival (p = 0.051), whereas in UV-associated AS, PD-1 expression correlated with better survival (p = 0.035). In conclusion, we show the presence of PD-1, PD-L1, and CD8 + T cells in the majority of AS but reveal differences between and within AS subgroups, providing prognostic information and indicating to be predictive for ICI.

Aberrant PTEN, PIK3CA, pMAPK, and TP53 expression in human scalp and face angiosarcoma

Angiosarcoma is a rare, highly aggressive malignant tumor originating from endothelial cells that line the lumen of blood or lymphatic vessels. The molecular mechanisms of scalp and face angiosarcoma still need to be elucidated. This study aimed to investigate the expression of phosphatase and tensin homolog (PTEN), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), phosphorylated mitogen-activated kinase-like protein (pMAPK), and tumor protein p53 (TP53) in scalp and face angiosarcoma and to assess tumor tissue apoptosis.The expression and intracellular distribution of PTEN, PIK3CA, pMAPK, and TP53 proteins in 21 specimens of human scalp and face angiosarcoma and 16 specimens of human benign hemangioma were evaluated using immunohistochemistry. Tumor cell apoptosis was assessed by terminal deoxyribonucleotide transferase-mediated dUTP nick end-labeling staining.Significantly lower PTEN but higher PIK3CA, pMAPK, and TP53 immunostaining were detected in the angiosarcoma specimens than in the benign hemangioma specimens(P < .01). The angiosarcoma tissues exhibited significantly higher apoptosis indices than the benign hemangioma tissues (P < .01). The positive expression rates of PIK3CA, pMAPK, and TP53 were correlated with the degree of tumor differentiation in the human scalp and face angiosarcoma.The PI3K, MAPK, and TP53 pathways might be involved in angiosarcoma tumorigenesis in humans and may serve as therapeutic targets for the effective treatment of this malignancy.