Expression of basic fibroblast growth factor and its receptor-1 in cardiac myxoma.

Background. To clarify the significance of basic fibroblast growth factor (bFGF) in angiogenesis or proliferative activity in cardiac myxoma, the expression of bFGF and its receptor (FGFR-1) were immunohisiochemically examined. Methods. Formalin-embedded tissues of cardiac myxomas were obtained by surgical resection from 15 patients and analyzed by immunostaining of bFGF and FGFR-1. The microvessel density was measured in the 15 myxomas using platelet derived endothelial cell adhesion molecule-1. For evaluation o proliferative activity of the cardiac myxomas, proliferating cell nuclear antigen (PCNA) immunostaining was performed, and the PCNA labeling index was measured in each section. Results. bFGF and FGFR-1 were observed in 73.3% and 67.7% of the myxomas, respectively. There was a close correlation between the expression of bFGF and FGFR-1. This co-expression was frequently observed in the myxoma cells around the microvessels appearing as a ring structure. Regarding possible relationships between the expression of bFGF or FGFR-1 and the clinicopathologic features, there were no parameters excluding the macroscopic type of myxoma. The microvessel density in the myxomas with bFGF or FGFR-1 expression was higher than that in myxomas without it. The PCNA labeling index in myxomas with bFGF expression was higher than that in myxoma without it, and the PCNA labeling index tended to be higher in myxomas with FGFR-1 expression than that in myxomas without it. Conclusions. bFGF and/or FGFR-1 was expressed in some of cardiac myxoma, and may be an important role for tumor angiogenesis and proliferative activity.