• uPARAP expression was assessed in sarcoma samples and normal tissues using tissue microarrays. • High uPARAP expression was observed in the majority of sarcoma subtypes analyzed. • uPARAP showed limited expression in normal tissues. • Most sarcoma subtypes did not show statistically significant associations between expression and selected clinical parameters or survival outcomes. • uPARAP is a highly promising target for therapies such as antibody-drug conjugates. Sarcomas are highly heterogenous and rare malignant tumors derived from mesenchymal cells. The current standard treatments for advanced disease have low response rates and are typically associated with considerable toxicity. The aim of this study was to investigate the expression of a potential novel therapeutic target and its clinical correlation in sarcomas, namely urokinase plasminogen activator receptor-associated protein (uPARAP/Endo180/CD280). We evaluated uPARAP expression in various sarcoma subtypes and in normal tissues using 12 tissue microarrays. Expression was assessed on immunohistochemically stained slides and scored according to staining intensity and the percentage of positive tumor cells. Clinical correlations between uPARAP expression and selected parameters (gender and sample origin) were analyzed using generalized estimating equations, and survival outcomes were evaluated with Kaplan-Meier and log-rank tests. Our results demonstrated limited uPARAP expression in normal tissues, while high expression was observed in the majority of analyzed sarcoma subtypes, particularly high (>80% of highly positive cases) in fibrosarcoma, synovial sarcoma, undifferentiated pleomorphic sarcoma, malignant peripheral nerve sheath tumor, and various bone sarcomas. Based on the correlation analyses between uPARAP expression and selected clinical parameters or survival outcomes, most subtypes did not show a statistically significant association. In conclusion, this study highlights the potential of uPARAP as an innovative target for targeted treatments, such as novel antibody-drug conjugates in sarcoma.
Wang et al. (Mon,) studied this question.