Close correlation between CXCR4 and VEGF expression and frequent CXCR7 expression in rhabdomyosarcoma

CXC chemokine receptor 4 (CXCR4) expression is reportedly correlated with both vascular endothelial growth factor (VEGF) expression and poor prognosis in a variety of cancers. Its relation to CXC chemokine receptor 7 (CXCR7) is also noted in several malignancies, including rhabdomyosarcoma (RMS) cell lines. However, the correlations between these chemokine receptors and angiogenic factors have not yet been adequately investigated in RMS clinical specimens. By immunohistochemistry, we assessed CXCR4, CXCR7, CC chemokine receptor 6, CC chemokine receptor 7, VEGF expression, microvessel density, and MIB-1 labeling index in 82 formalin-fixed RMS specimens, including 34 primary alveolar RMS and 44 primary embryonal RMS (ERMS). Twenty-six frozen samples were available for investigation by quantitative reverse transcription polymerase chain reaction to detect the messenger RNA expression levels of these molecules. We also evaluated their significance with respect to clinicopathological factors and patient survival rates. Primary RMS showed high expression of CXCR7 (83.1%) regardless of the histologic subtype. High cytoplasmic CXCR4 and high VEGF expression revealed significant correlations in both ERMS and alveolar RMS (P = .0051 and P = .0003, respectively). By univariate analysis of ERMS cases, the tumors with high VEGF expression showed significantly poor prognoses (P = .0017). High VEGF expression also was the independent adverse prognostic factor for ERMS. Because CXCR4, CXCR7, and VEGF are widely expressed in RMS, the combination of these antagonists may provide a potential target for molecular therapy.