Contrasting Prognostic Implications of Platelet-Derived Growth Factor Receptor-β and Vascular Endothelial Growth Factor Receptor-2 in Patients with Angiosarcoma

Background. Angiosarcoma is an extremely rare tumor among sarcomas and comprises a heterogeneous group of high-grade vascular malignancies. Our study aimed to examine the correlations between 6 immunohistochemical biomarkers-stem cell factor receptor (KIT), platelet-derived growth factor receptor (PDGFR)-alpha, PDGFR-beta, vascular endothelial growth factor receptor (VEGFR)-1, VEGFR-2, and VEGFR-3-and overall survival (OS) in patients with angiosarcomas. Methods. Immunohistochemical analyses for the 6 biomarkers were performed by using tumor specimens obtained from 34 patients with angiosarcomas. Correlations between biomarkers were examined by Fisher's exact test. For each biomarker, the correlation between the immunohistochemical score and OS was examined by the log-rank test and Cox regression analysis. Results. The percentages of angiosarcoma patients with positive expressions (immunohistochemical score > 0) of KIT, PDGFR-alpha, PDGFR-beta, VEGFR-1, VEGFR-2, and VEGFR-3 were 14.7%, 11.8%, 88.2%, 61.8%, 94.1%, and 100.0%, respectively. No statistically significant correlations between any 2 biomarkers were observed. Cox regression analysis demonstrated a significant positive correlation between short OS and the immunohistochemical score for PDGFR-beta and between long OS and the immunohistochemical score for VEGFR-2. Conclusion. Increased expression of PDGFR-beta may be a statistically significant prognostic factor for poor OS, while increased expression of VEGFR-2 may be a favorable prognostic factor for patients with angiosarcoma.